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Diagnostic Aids

Perform this test when instructed by QUICK TEST . This test is only intended to diagnose:

Fig 1: DPFE Sensor Wiring Harness Connector Terminals
G95G35978
Fig 2: EVR Solenoid Wiring Harness Connector Terminals
G95B35981
Fig 3: DPFE System Components
G95C35982
  1. Step 1) DTC P1400: Check DPFE Voltage  This code indicates open in DPFE SIG circuit. Possible causes for this fault are:
    • Leaking upstream pressure hose.
    • DPFE SIG shorted to GND or SIG RTN circuit.
    • VREF shorted to GND or SIG RTN circuit.
    • Faulty DPFE sensor.
    • Faulty PCM.

    Turn ignition off. Connect scan tester to DLC. Turn ignition on. Using scan tester, access DPFEGR PID. If voltage is less than 0.2 volt, go to next step. If voltage is 0.2 volt or more, go to step 6).

  2. Step 2) Generate Opposite DPFE Signal  Turn ignition off. Disconnect DPFE wiring harness connector. Using a jumper wire, connect DPFE SIG and VREF terminals at wiring harness connector. Turn ignition on. Using scan tester, access DPFE SIG PID. If scan tester error occurs, disconnect jumper wire and go to step 3). If DPFEGR PID value is not 4-6 volts, go to step 3). If DPFEGR PID value is 4-6 volts, replace DPFE sensor and repeat QUICK TEST .
  3. Step 3) Measure VREF Voltage At DPFE Sensor  Leave DPFE sensor disconnected. Turn ignition on. Measure voltage between SIG RTN terminal and VREF terminal at DPFE wiring harness connector. If voltage is 4-6 volts, go to step 4). If voltage is not 4-6 volts, go to CIRCUIT TEST C.
  4. Step 4) Check DPFE SIG For Short To Ground  Leave DPFE sensor disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and 91 (SIG RTN) and test pins No. 51 and 103 (PWR GND). If each measurement is 10,000 ohms or more, replace PCM and repeat QUICK TEST. If any measurement is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 6). No test procedures have been omitted.
  5. Step 6) Wiggle Test Sensor & Harness  With ignition off, connect scan tester to DLC. Turn ignition on. Access DPFE PID with scan tester. Observe DPFE PID for indication of fault while shaking and bending DPFE sensor wiring harness and connector. Tap lightly on DPFE sensor to simulate road shock. An indication of fault is a sudden change in DPFE PID voltage. If fault is indicated, isolate and repair as necessary. If no fault is indicated, go to CIRCUIT TEST Z.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 10). No test procedures have been omitted.
  6. Step 10) DTC P1401: Check DPFE Signal Voltage  This code indicates PCM has detected DPFE SIG circuit input above maximum. Possible causes for this fault are:
    • Open circuit in DPFE SIG or SIG RTN circuit.
    • DPFE SIG shorted to VREF or PWR circuit.
    • VREF shorted to PWR circuit.
    • Faulty DPFE sensor.
    • Faulty PCM.

    With ignition off, connect scan tester to DLC. Turn ignition on. Access DPFEGR PID. If voltage is more than 4.0 volts, go to next step. If voltage is 4.0 volts or less, go to step 19).

  7. Step 11) Check DPFE SIG For Short To Power  Turn ignition off. Disconnect DPFE wiring harness connector. Turn ignition on. Measure voltage between DPFE SIG terminal at wiring harness connector and negative battery terminal. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, go to step 13).
  8. Step 12) Leave ignition off and DPFE sensor disconnected. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 65 (DPFE SIG) and test pins No. 51 and 103 (PWR GND) at breakout box. If voltage is 10.5 volts or more, repair short between DPFE SIF and PWR circuit. Repeat QUICK TEST. If voltage is less than 10.5 volts, replace PCM and repeat QUICK TEST .
  9. Step 13) Generate Opposite DPFE Signal  Turn ignition off. Disconnect DPFE wiring harness connector. Using a jumper wire, connect DPFE SIG and SIG RTN terminals at wiring harness connector. Turn ignition on. Using scan tester, access DPFEGR SIG PID. If scan tester error occurs, disconnect jumper wire and go to step 18). If DPFEGR PID value is .05 volt or more, go to step 16). If DPFEGR PID value is less than .05 volt, disconnect jumper wire and go to next step.
  10. Step 14) Verify VREF Is Within Range  Leave DPFE sensor disconnected. Turn ignition on. Measure voltage between SIG RTN terminal and VREF terminal at DPFE wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.
  11. Step 15) Check DPFE SIG For Short To VREF  Leave DPFE sensor disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and 90 (VREF) at breakout box. If resistance is 10,000 ohms or more, replace DPFE sensor and repeat QUICK TEST. If resistance is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
  12. Step 16) Check DPFE SIG For Open Circuit  Leave ignition off and DPFE sensor disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and DPFE SIG terminal at DPFE sensor wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST .
  13. Step 17) Check SIG RTN For Open Circuit  Leave ignition off and DPFE sensor disconnected. Measure resistance between test pin No. 91 (SIG RTN) and SIG RTN terminal of DPFE sensor wiring harness connector. If resistance is less than 5 ohms, replace PCM and repeat QUICK TEST. If resistance is 5 ohms or more, repair open in SIG RTN circuit and repeat QUICK TEST .
  14. Step 18) Check DPFE SIG For Short To VREF  Leave ignition off and DPFE sensor disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and 90 (VREF) at breakout box. If resistance is more than 10,000 ohms, replace PCM and repeat QUICK TEST. If resistance is 10,000 ohms or less, repair short between DPFE SIG and VREF circuit. Repeat QUICK TEST .
  15. Step 19) Wiggle Test Sensor & Harness  With ignition off, connect scan tester to DLC. Turn ignition on. Access DPFE PID with scan tester. Observe DPFE PID for indication of fault while shaking and bending DPFE sensor wiring harness and connector. An indication of fault is a sudden change in DPFE PID voltage. Tap lightly on DPFE sensor to simulate road shock. If fault is indicated, isolate and repair as necessary. If no fault is indicated, go to CIRCUIT TEST Z.
  16. Step 20) DTC P0402: Check EGR Flow At Idle  This code indicates PCM has detected EGR flow at idle. Possible causes for this fault are:
    • EGR valve stuck open.
    • EVR solenoid vent plugged.
    • EVR circuit shorted to ground.
    • Excessively worn or damaged vacuum hose.
    • Faulty EVR solenoid.
    • Faulty PCM.
    NOTE: If Continuous Memory Code P1405 is present, go to step 50).

    With ignition off, disconnect and plug EGR vacuum hose. Perform KOER self-test. If DTC P0402 is present, service or replace EGR valve. If DTC P0402 is not present or vehicle will not start/run, go to next step.

  17. Step 21) Turn ignition off. Reconnect EGR vacuum hose. Perform KOER self-test. If DTC P0402 is present, go to next step. If DTC P0402 is not present or vehicle will not start/run, go to step 30).
  18. Step 22) Check EGR System  Using vehicle's vacuum diagram label, check EGR system vacuum hoses for damage, tight connections and correct routing. If hoses are okay, go to next step. If hoses are not okay, repair as necessary. Clear PCM memory and repeat QUICK TEST .
  19. Step 23) Check DPFE Sensor Output  Turn ignition off. Disconnect pressure hoses at DPFE sensor. Connect vacuum pump to DPFE sensor downstream port marked REF. Turn ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Using vacuum pump, apply 8-9 in. Hg. PID voltage should be more than 4 volts. When vacuum is quickly released, PID voltage should drop to less than one volt. If PID voltage is not as specified, replace DPFE sensor and repeat QUICK TEST . If PID voltage is as specified, go to next step.
  20. Step 24) Check EGR Flow At Idle With EVR Solenoid Disconnected  Turn ignition off. Disconnect EGR valve vacuum hose. Connect vacuum gauge to hose. Start engine and allow to idle. While observing vacuum gauge, disconnect EVR solenoid. If vacuum gauge reads 1.6 in. Hg or more, go to next step. If vacuum gauge reads less than 1.6 in. Hg, go to step 26).
  21. Step 25) Check EVR Vent  Turn ignition off. Disconnect EVR solenoid vent cap and vacuum hoses. Remove EVR filter and inspect for restriction. Using a vacuum pump, apply 15 in. Hg to EVR vent. If EVR solenoid is plugged or restricted, repair or replace as necessary. Clear PCM memory and repeat QUICK TEST. If solenoid is not plugged or restricted, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
  22. Step 26) Check EVR Solenoid Coil Resistance  Turn ignition off. Disconnect EVR solenoid wiring harness connector. Measure resistance between EVR terminals. If resistance is 26-40 ohms, go to next step. If resistance is not 26-40 ohms, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
  23. Step 27) Check EVR Circuit For Short To Ground  Leave ignition off and EVR solenoid disconnected. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 47 (EVR) and test pins No. 51 and 103 (PWR GND) at breakout box. If resistance is more than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair short between EVR circuit and ground.
  24. Step 28) Check EVR Circuit For Short To VREF  Leave ignition off and EVR solenoid disconnected. Measure resistance between test pin No. 47 (EVR) and test pins No. 90 (VREF) at breakout box. If resistance is more than 10,000 ohms, replace PCM and repeat QUICK TEST . If resistance is 10,000 ohms or less, repair short between EVR circuit and VREF circuit.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 28) to step 30). No test procedures have been omitted.
  25. Step 30) Check DPFE Sensor Output  Leave ignition off. Connect scan tester to DLC. Disconnect pressure hoses at DPFE sensor. Connect vacuum pump to DPFE sensor port marked REF. Turn ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Apply 9 in. Hg to DPFE sensor. PID voltage should be more than 4.0 volts. Release vacuum from sensor. PID voltage should drop to less than one volt in less than 3 seconds. If voltage readings are as specified, go to next step. If voltage readings are not as specified, replace DPFE sensor. Clear PCM memory and repeat QUICK TEST .
  26. Step 31) Check DPFE SIG Voltage  Leave ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Connect vacuum hose to EGR valve and plug hose. Start engine and allow to idle. Observe DPFEGR PID voltage at idle and compare to KOEO voltage. If voltage is higher at idle, apply 2-3 in. Hg to EGR valve and release vacuum. Repeat several times while observing DPFEGR PID voltage on scan tool. DPFEGR PID voltage should increase as valve begins to open and return to initial value as vacuum is released. A slow to return voltage is an indication of a slow closing EGR valve. If DPFEGR PID does not indicate fault, go to next step. If fault is indicated by DPFE PID, service or replace EGR VALVE. Clear PCM memory and repeat QUICK TEST .
  27. Step 32) Check EGR Valve Vacuum While Wiggling EVR Circuit  Turn ignition off. Disconnect vacuum hose at EGR valve and connect to vacuum gauge. Turn ignition on. Observe vacuum gauge for indication of fault while wiggling EVR wiring harness and connector. Fault is indicated by a sudden jump in vacuum reading. Tap lightly on sensor to simulate road shock. If no faults are indicated, go to next step. If fault is indicated, isolate and repair as necessary. Clear PCM memory and repeat QUICK TEST .
  28. Step 33) Check EVR Solenoid For Restriction  Turn ignition off. Disconnect EVR solenoid vent filter. Inspect for contamination or water. Remove EGR vacuum hose and inspect for restriction. Repair or replace as necessary. If no faults can be found, problem is intermittent and cannot be identified at this time. Go to CIRCUIT TEST Z.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 33) to step 40). No test procedures have been omitted.
  29. Step 40) DTC P1403: Check For Reversed Pressure Hoses  Check hoses for proper connection. DPFE port marked HI should connect to exhaust side of orifice tube. DPFE port marked REF should connect to intake side of orifice tube. See Fig 4. If hoses are not routed correctly, repair as necessary. Clear PCM memory and repeat QUICK TEST. If hoses are routed correctly, problem cannot be identified at this time. Clear PCM memory and repeat QUICK TEST .
    Fig 4: Identifying DPFE Vacuum Circuit
    G94F32511
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 40) to step 50). No test procedures have been omitted.
  30. Step 50) DTC P1405: Check For Upstream Pressure Hose Connection  Check upstream hose for clean, tight connection. See Fig 4. Repair as necessary. Clear PCM memory and repeat QUICK TEST . If hose is okay, go to next step.
  31. Step 51) Inspect Upstream Pressure Hose  Check upstream hose for clean, tight connection. Ensure hose is not pinched, wet or contaminated. Repair as necessary. Clear PCM memory and repeat QUICK TEST . If hose is okay, go to next step.
  32. Step 52) Inspect Orifice Tube Assembly & DPFE Sensor  Check DPFE sensor port for restriction or damage. Inspect exhaust manifold side pressure pick-up tube at the orifice tube assembly for restriction or damage. Repair as necessary. Clear PCM memory and repeat QUICK TEST. If no faults are found, clear PCM memory and repeat QUICK TEST . If hose is okay, go to next step.
  33. Step 53) Check DPFE Sensor Output  Leave ignition off. Connect scan tester to DLC. Disconnect pressure hoses at DPFE sensor. Connect vacuum pump to DPFE sensor port marked REF. Turn ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Apply 9 in. Hg to DPFE sensor. PID voltage should be more than 4.0 volts. Release vacuum from sensor. PID voltage should drop to less than one volt in less than 3 seconds. If voltages not as specified, replace DPFE sensor and repeat QUICK TEST . If voltage readings are as specified, fault is intermittent and cannot be duplicated at this time. Clear PCM memory and repeat QUICK TEST.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 53) to step 60). No test procedures have been omitted.
  34. Step 60) DTC P1406: Check For Downstream Pressure Hose Connection  Check downstream hose for clean, tight connection. See Fig 4. Repair as necessary. Clear PCM memory and repeat procedures under QUICK TEST . If hose is okay, go to next step.
  35. Step 61) Inspect Downstream Pressure Hose  Check downstream hose for clean, tight connection. Ensure hose is original equipment. Ensure hose is not pinched, wet or contaminated. Repair as necessary. Clear PCM memory and repeat QUICK TEST . If hose is okay, go to next step.
  36. Step 62) Inspect Orifice Tube Assembly & DPFE Sensor  Check DPFE sensor port for restriction or damage. Inspect intake manifold side pressure pick-up tube at the orifice tube assembly for restriction or damage. Repair as necessary. Clear PCM memory and repeat QUICK TEST . If no faults are found, go to next step.
  37. Step 63) Check DPFE Sensor Output  Leave ignition off. Connect scan tester to DLC. Disconnect pressure hoses at DPFE sensor. Connect vacuum pump to DPFE sensor port marked REF. Turn ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Apply 9 in. Hg to DPFE sensor. PID voltage should be more than 4.0 volts. Release vacuum from sensor. PID voltage should drop to less than one volt in less than 3 seconds. If voltages not as specified, replace DPFE sensor and repeat QUICK TEST. If voltage readings are as specified, fault is intermittent and cannot be duplicated at this time. Clear PCM memory and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 63) to step 70). No test procedures have been omitted.
  38. Step 70) DTC P0401  These codes indicate self-test has detected no EGR flow. Possible causes are as follows:
    • EGR valve stuck closed.
    • EGR valve diaphragm leak.
    • EGR flow plugged or restricted.
    • Faulty EGR hose.
    • EVR VPWR circuit open.
    • EVR VPWR circuit to PCM open or shorted to PWR.
    • DPFE sensor VPWR circuit open.
    • DPFE sensor hoses faulty.
    • Faulty DPFE sensor.
    • Faulty EVR solenoid.
    • Faulty PCM.

    If fault is currently present, KOER code P1408 should be present. Perform KOER SELF-TEST . If DTC P1408 is present, go to next step. If DTC P1408 is not present, go to step 90).

  39. Step 71) DTC P1408  This code indicates KOER SELF-TEST  has detected EGR flow out of range. Possible causes are as follows:
    • EGR valve stuck closed.
    • EGR valve diaphragm leak.
    • EGR flow plugged or restricted.
    • Faulty EGR hose.
    • EVR VPWR circuit open.
    • EVR VPWR circuit to PCM open or shorted to PWR.
    • DPFE sensor VPWR circuit open.
    • DPFE sensor hoses faulty or reversed.
    • Downstream pressure hoses plugged or removed.
    • Faulty orifice tube assembly.
    • Faulty DPFE sensor.
    • Faulty EVR solenoid.
    • Faulty PCM.

    Retrieve Continuous Memory DTCs. If any codes except DTCs P1403 or P1406 are present, service as necessary before continuing. If DTC 1406 is present, go to step 60). If no codes are present, go to next step.

  40. Step 72) Perform KOER SELF-TEST While Monitoring EGR Vacuum  Disconnect vacuum hose from EGR valve. Connect hose to vacuum gauge. Perform KOER SELF-TEST  while monitoring gauge. Disregard DTCs set during this test. During test, if EGR vacuum should rise to 3.0 in. Hg or more, go to next step. If vacuum stays below 3.0 in. Hg, go to step 80).
  41. Step 73) Inspect DPFE Pressure Hoses  Check both hoses for correct routing. Ensure hoses are not restricted or plugged or leaking. Inspect DPFE sensor and orifice tube assembly for restriction or damage at pick-up tube. If no faults are found, go to next step. If faults are found, repair or replace as necessary. Clear PCM memory and repeat QUICK TEST .
  42. Step 74) Check VREF Voltage At DPFE Sensor  Turn ignition off. Disconnect DPFE sensor wiring harness connector. Turn ignition on. Measure voltage between VREF terminal and SIG RTN terminal at DPFE sensor wiring harness connector. If voltage is 4-6 volts, reconnect DPFE sensor and go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.
  43. Step 75) Vacuum Check DPFE Sensor Output  Turn ignition off. Connect scan tester to DLC. Disconnect pressure hoses at DPFE sensor. Connect vacuum pump to DPFE sensor port marked REF. Turn ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Apply 8-9 in. Hg to DPFE sensor. PID voltage should be more than 4.0 volts. Release vacuum from sensor. PID voltage should drop to less than one volt in less than 3 seconds. If voltage readings are not as specified, replace DPFE sensor. Clear PCM memory and repeat QUICK TEST . If voltages are as specified, go to next step.
  44. Step 76) Check EGR Valve Function  Turn ignition off. Leave scan tester connected to DLC. Disconnect and plug hose at EGR valve. Connect vacuum pump to EGR valve. Start engine and allow to idle. Using scan tester, access DPFEGR and RPM PIDs. Slowly apply 5-10 in. Hg to EGR valve and hold for 10 seconds. It may be necessary to increase engine speed to maintain 800 RPM. EGR valve should start to open at about 1.6 in. Hg. of vacuum, indicated by increasing DPFEGR PID voltage. DPFEGR PID voltage should increase to 2.5 volts (EGR fully open). DPFGER PID voltage should hold steady when vacuum is held. If voltage drops within a few seconds, EGR valve or vacuum source may be leaking. If DPFEGR PID voltage is as specified, reconnect all components and go to step 85). If DPFEGR PID voltage is not as specified, check the following and repair as necessary:
    • Remove and inspect EGR for signs of contamination, unusual wear, carbon deposits, binding, leaking diaphragm and other damage.
    • Obstructed EGR port in the intake manifold.
    After repair, reconnect all components, clear PCM memory and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 76) to step 80). No test procedures have been omitted.
  45. Step 80) Check EVR Solenoid Vacuum  Inspect EVR solenoid and EGR vacuum hoses for leaks, restrictions, damage or incorrect routing. Repair as necessary. Disconnect vacuum hoses at EVR solenoid. Connect vacuum pump to EVR solenoid vacuum supply hose. Start engine and allow to idle. If vacuum gauge reading is 15 in. Hg or more, go to next step. If vacuum gauge reading is less than 15 in. Hg, isolate fault and repair as necessary. Clear PCM memory and repeat QUICK TEST .
  46. Step 81) Check VPWR To EVR Solenoid  Turn ignition off. Disconnect EVR solenoid wiring harness connector. Turn ignition on. Measure voltage between VPWR terminal at EVR solenoid wiring harness connector and chassis ground. If voltage 10.5 volts or more, go to next step. If voltage less than 10.5 volts, repair open in VPWR circuit. Clear PCM memory and repeat QUICK TEST .
  47. Step 82) Check Resistance At EVR Solenoid  Turn ignition off. Leave EVR solenoid wiring harness connector disconnected. Measure resistance across EVR solenoid terminals. If resistance is 26-40 ohms, go to next step. If resistance is not 26-40 ohms, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
  48. Step 83) Check EVR For Short To PWR  Leave EVR solenoid disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damage pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 47 (EVR) at breakout box and chassis ground. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair EVR circuit short to PWR. Clear PCM memory and repeat QUICK TEST .
  49. Step 84) Check EVR Circuit For Open In Harness  Leave ignition off and EVR solenoid disconnected. Measure resistance between test pin No. 47 (EVR) and EVR terminal at EVR solenoid wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in EVR circuit. Clear PCM memory and repeat QUICK TEST .
  50. Step 85) Check EVR Solenoid Vacuum Output Capability  Leave ignition off. Connect EVR solenoid to wiring harness connector. Connect PCM to breakout box. Disconnect hose from EGR valve. Connect EGR vacuum hose to vacuum gauge. Start engine and allow to idle. Connect test pin No. 47 (EVR) at breakout box to chassis ground. If vacuum gauge reading is 4 in. Hg or more, replace PCM and repeat QUICK TEST. If vacuum gauge is less than 4 in. Hg, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 85) to step 90). No test procedures have been omitted.
  51. Step 90) Check EGR System  Leave ignition off. Check entire EGR system for deterioration or signs of failure. Repair or replace as necessary. If system is okay, go to next step.
  52. Step 91) Check EGR Valve Operation  Leave ignition off. Disconnect EGR valve. Connect vacuum pump to EGR valve. Connect scan tester to DLC. Disconnect and plug hose at EGR valve. Connect vacuum pump to EGR valve. Start engine and allow to idle. Using scan tester, access DPFEGR PIDs. Slowly apply 5-10 in. Hg to EGR valve and hold for 5 seconds. It may be necessary to increase engine speed to avoid stalling. When vacuum increases, PID voltage should increase as EGR valve opens. EGR operation should be smooth with no binding. If EGR valve opens smoothly and holds vacuum, go to next step. If EGR valve is not as specified, service or replace EGR valve. Clear PCM memory and repeat QUICK TEST .
    NOTE: In cold climate, EGR valve may freeze shut and thaw when engine warms, causing intermittent trouble code to be set in PCM memory.
  53. Step 92) Check EVR For Short To PWR  Turn ignition off. Leave EGR valve hose connected to vacuum gauge. Disconnect PCM 104-pin connector. Inspect for damage pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Turn ignition on. Connect jumper wire between test pin No. 47 (EVR) at breakout box and chassis ground to turn EVR on. Vacuum gauge reading should be more than 4.0 in. Hg. Observe vacuum gauge for fault while tapping lightly on EVR solenoid. Fault will be indicated by a sudden drop of vacuum. Wiggle EVR vacuum hoses, wiring harness and connector. If fault is indicated, isolate and repair as necessary. Clear PCM memory and repeat QUICK TEST . If no faults are indicated, symptom cannot be identified at this time. Go to CIRCUIT TEST Z.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 92) to step 110). No test procedures have been omitted.
  54. Step 110) DTC P1409  This code indicates self-test has detected electrical malfunction in EVR circuit. Possible causes are as follows:
    • EVR circuit open or shorted.
    • Faulty EVR solenoid.
    • Faulty PCM.

    Turn ignition off. Leave EVR solenoid wiring harness connector disconnected. Measure resistance across EVR solenoid terminals. If resistance is 26-40 ohms, go to next step. If resistance is not 26-40 ohms, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .

  55. Step 111) Check VPWR To EVR Solenoid  Turn ignition off. Disconnect EVR solenoid wiring harness connector. Turn ignition on. Measure voltage between VPWR terminal at EVR solenoid wiring harness connector and chassis ground. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open in VPWR circuit. Clear PCM memory and repeat QUICK TEST .
  56. Step 112) Check EVR Circuit Continuity  Leave ignition off and EVR solenoid disconnected. Disconnect PCM 104-pin connector. Inspect for damage pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 47 (EVR) and EVR terminal at EVR solenoid wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in EVR circuit. Clear PCM memory and repeat QUICK TEST .
  57. Step 113) Check EVR For Short To PWR  Leave EVR solenoid disconnected. Turn ignition off. Turn ignition on. Measure resistance between test pin No. 47 (EVR) and test pins No. 71 and 97 (VPWR) at breakout box. Measure resistance between test pin No. 47 (EVR) and test pins No. 24 and 103 (PWR GND) at breakout box. If each resistance is more than 10,000 ohms, replace PCM and repeat QUICK TEST. If any resistance is less than 10,000 ohms, repair EVR circuit short to PWR or PWR GND and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 113) to step 120). No test procedures have been omitted.
  58. Step 120) Continuous Memory DTC P1409  This continuous DTC indicates self-test has detected electrical malfunction in EVR circuit. Possible causes are as follows:
    • EVR circuit open or shorted.
    • Faulty EVR solenoid.
    • Faulty PCM.

    Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 47 (EVR) and No. 24 (PWR GND) at breakout box. Voltage should be more than 10.5 volts. Observe voltmeter for indication of fault while wiggling EVR wiring harness and connector. Fault is indicated by a sudden jump in voltage reading. Tap lightly on sensor to simulate road shock. If fault is indicated, isolate and repair as necessary. If no faults are indicated, symptom cannot be identified at this time. Go to CIRCUIT TEST Z.

    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 120) to step 130). No test procedures have been omitted.
  59. Step 130) DTC P0400  This code indicates EGR system malfunction. Turn ignition off. Connect scan tester to DLC. Turn ignition on. Using scan tester, access DPFEGR PID. If voltage is more than 0.2 volt, go to next step. If voltage is 0.2 volt or more, go to step 134).
  60. Step 131) Leave ignition on. If DPFEGR PID value is less than 4 volts, go to next step. If DPFE PID value is 4 volts or more, go to step 137).
  61. Step 132) Start engine and allow to idle. If engine will not start/run, go to next step. If DPFEGR PID value increases by 0.15 volt or more, go to next step. If DPFEGR PID voltage increases by less than 0.15 volt, go to step 160).
  62. Step 133) Turn ignition off. Disconnect and plug EGR hose. Compare voltage to previous voltage. If DPFEGR PID value increases by 0.15 volt or more, service or replace EGR valve and repeat QUICK TEST . If DPFEGR PID voltage does not increase by 0.15 volt, go to step 150).
  63. Step 134) Generate Opposite DPFE Signal  Turn ignition off. Disconnect DPFE wiring harness connector. Using a jumper wire, connect DPFE SIG and VREF terminals at wiring harness connector. Turn ignition on. Using scan tester, access DPFEGR PID. If scan tester error occurs, disconnect jumper wire and go to next step. If DPFEGR PID value is not 4-6 volts, remove jumper wire and go to next step. If DPFEGR PID value is 4-6 volts, replace DPFE sensor and repeat QUICK TEST .
  64. Step 135) Measure VREF Voltage At DPFE Sensor  Leave DPFE sensor disconnected. Turn ignition on. Measure voltage between SIG RTN terminal and VREF terminal at DPFE wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.
  65. Step 136) Check DPFE SIG For Short To Ground  Leave DPFE sensor disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and test pins No. 91 (SIG RTN), 51 and 103 (PWR GND). If each measurement is 10,000 ohms or more, replace PCM and repeat QUICK TEST. If any measurement is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
  66. Step 137) Check DPFE SIG For Short To Power  Turn ignition off. Disconnect DPFE wiring harness connector. Turn ignition on. Measure voltage between DPFE SIG terminal at wiring harness connector and negative battery terminal. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, go to step 139).
  67. Step 138) Leave ignition off and DPFE sensor disconnected. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 65 (DPFE SIG) and test pins No. 51 and 103 (PWR GND) at breakout box. If voltage is 10.5 volts or more, repair short between DPFE SIF and PWR circuit. Repeat QUICK TEST. If voltage is less than 10.5 volts, replace PCM and repeat QUICK TEST .
  68. Step 139) Generate Opposite DPFE Signal  Turn ignition off. Disconnect DPFE wiring harness connector. Using a jumper wire, connect DPFE SIG and SIG RTN terminals at wiring harness connector. Turn ignition on. Using scan tester, access DPFEGR SIG PID. If scan tester error occurs, disconnect jumper wire and go to step 144). If DPFEGR PID value is .05 volt or more, go to step 142). If DPFEGR PID value is less than .05 volt, remove jumper wire and go to next step.
  69. Step 140) Verify VREF Is Within Range  Leave DPFE sensor disconnected. Turn ignition on. Measure voltage between SIG RTN terminal and VREF terminal at DPFE wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.
  70. Step 141) Check DPFE SIG For Short To VREF  Leave DPFE sensor disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and 90 (VREF) at breakout box. If resistance is 10,000 ohms or more, replace DPFE sensor and repeat QUICK TEST. If resistance is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
  71. Step 142) Check DPFE SIG For Open Circuit  Leave ignition off and DPFE sensor disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and DPFE SIG terminal at DPFE sensor wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST .
  72. Step 143) Check SIG RTN For Open Circuit  Leave ignition off and DPFE sensor disconnected. Measure resistance between test pin No. 91 (SIG RTN) and SIG RTN terminal of DPFE sensor wiring harness connector. If resistance is less than 5 ohms, replace PCM and repeat QUICK TEST. If resistance is 5 ohms or more, repair open in SIG RTN circuit and repeat QUICK TEST .
  73. Step 144) Check DPFE SIG For Short To VREF  Leave ignition off and DPFE sensor disconnected. Measure resistance between test pin No. 65 (DPFE SIG) and 90 (VREF) at breakout box. If resistance is more than 10,000 ohms, replace PCM and repeat QUICK TEST. If resistance is 10,000 ohms or less, repair short between DPFE SIG and VREF circuit. Repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 144) to step 150). No test procedures have been omitted.
  74. Step 150) Check EGR System Vacuum Hoses  Using vehicle's vacuum diagram label, check EGR system vacuum hoses for damage, tight connections and correct routing. If hoses are okay, go to next step. If hoses are not okay, repair as necessary. Clear PCM memory and repeat QUICK TEST .
  75. Step 151) Check EGR Flow At Idle With EVR Solenoid Disconnected  Turn ignition on. Using scan tester, not DPEGR PID voltage. Disconnect EVR solenoid connector. Start engine and allow to idle. If DPFEGR PID value increases by 0.15 volt or more, go to next step. If DPFEGR PID voltage increase by less than 0.15 volt, go to step 153).
  76. Step 152) Check EVR Vent  Turn ignition off. Disconnect EVR solenoid vent cap and vacuum hoses. Remove EVR filter and inspect for restriction. Using a vacuum pump, apply 15 in. Hg to EVR vent. If EVR solenoid is plugged or restricted, repair or replace as necessary. Clear PCM memory and repeat QUICK TEST. If solenoid is not plugged or restricted, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
  77. Step 153) Check EVR Solenoid Coil Resistance  Turn ignition off. Disconnect EVR solenoid wiring harness connector. Measure resistance between EVR terminals. If resistance is 26-40 ohms, go to next step. If resistance is not 26-40 ohms, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
  78. Step 154) Check DPFE Sensor Output  Leave ignition off. Connect scan tester to DLC. Disconnect pressure hoses at DPFE sensor. Connect vacuum pump to DPFE sensor port marked REF. Turn ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Apply 9 in. Hg to DPFE sensor. PID voltage should be more than 4.0 volts. Release vacuum from sensor. PID voltage should drop to less than one volt in less than 3 seconds. If voltage readings are as specified, go to next step. If voltages are not as specified, replace DPFE sensor. Clear PCM memory and repeat QUICK TEST .
  79. Step 155) Check EVR Circuit For Short To Ground  Leave ignition off and EVR solenoid disconnected. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 47 (EVR) and test pins No. 51 and 103 (PWR GND) at breakout box. If resistance is more than 10,000 ohms, replace PCM and repeat QUICK TEST . If resistance is 10,000 ohms or less, repair short between EVR circuit and ground.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 155) to step 160). No test procedures have been omitted.
  80. Step 160) Check For Reversed Pressure Hoses  Check hoses for proper connection. DPFE port marked HI should connect to exhaust side of orifice tube. DPFE port marked REF should connect to intake side of orifice tube. See Fig 4. If hoses are not routed correctly, repair as necessary. Clear PCM memory and repeat QUICK TEST . If hoses are routed correctly, go to next step.
  81. Step 161) Inspect Pressure Hoses  Check both pressure hoses between DPFE sensor and EGR orifice tube for clean, tight connection. Ensure hoses are original equipment. Ensure hose is not pinched, wet, frozen or contaminated. Repair as necessary. Clear PCM memory and repeat QUICK TEST . If hoses are okay, go to next step.
  82. Step 162) Vacuum Check DPFE Sensor Output  Turn ignition off. Connect scan tester to DLC. Disconnect pressure hoses at DPFE sensor. Connect vacuum pump to DPFE sensor port marked REF. Turn ignition on. Using scan tester, access DPFEGR PID. PID voltage should be 0.2-0.7 volt. Apply 8-9 in. Hg to DPFE sensor. PID voltage should be more than 4.0 volts. Release vacuum from sensor. PID voltage should drop to less than one volt in less than 3 seconds. If voltage readings are as specified, go to next step. If voltages are not as specified, replace DPFE sensor. Clear PCM memory and repeat QUICK TEST .
  83. Step 163) Check EGR Valve Function  Turn ignition off. Leave scan tester connected to DLC. Disconnect and plug hose at EGR valve. Connect vacuum pump to EGR valve. Start engine and allow to idle. Using scan tester, access DPFEGR and RPM PIDs. Slowly apply 5-10 in. Hg to EGR valve and hold for 10 seconds. It may be necessary to increase engine speed to avoid stalling. As vacuum increases, PID voltage should rise above 2.5 volts. When vacuum is held steady, PID voltage should hold steady. If vacuum is as specified, reconnect all components and go to next step. If vacuum is not as specified, service or replace EGR valve. Clear PCM memory and repeat QUICK TEST .
  84. Step 164) Check EVR Solenoid Vacuum  Inspect EVR solenoid and EGR vacuum hoses for leaks, restrictions, damage or incorrect routing. Repair as necessary. Disconnect vacuum hoses at EVR solenoid. Connect vacuum pump to EVR solenoid vacuum supply hose. Start engine and allow to idle. If vacuum gauge reading is 15 in. Hg or more, go to next step. If vacuum gauge reading is less than 15 in. Hg, isolate fault and repair as necessary. Clear PCM memory and repeat QUICK TEST .
  85. Step 165) Check VPWR To EVR Solenoid  Turn ignition off. Disconnect EVR solenoid wiring harness connector. Turn ignition on. Measure voltage between VPWR terminal at EVR solenoid wiring harness connector and chassis ground. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open in VPWR circuit. Clear PCM memory and repeat QUICK TEST .
  86. Step 166) Check Resistance at EVR Solenoid  Turn ignition off. Leave EVR solenoid wiring harness connector disconnected. Measure resistance across EVR solenoid terminals. If resistance is 26-40 ohms, go to next step. If resistance is not 26-40 ohms, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
  87. Step 167) Check EVR For Short To PWR  Leave EVR solenoid disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect EEC-V Breakout Box (014-000950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 47 (EVR) at breakout box and chassis ground. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair EVR circuit short to PWR. Clear PCM memory and repeat QUICK TEST .
  88. Step 168) Check EVR Circuit For Open In Harness  Leave ignition off and EVR solenoid disconnected. Measure resistance between test pin No. 47 (EVR) and EVR terminal at EVR solenoid wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in EVR circuit. Clear PCM memory and repeat QUICK TEST .
  89. Step 169) Check EVR Solenoid Vacuum Output Capability  Leave ignition off. Reconnect EVR solenoid to wiring harness connector. Connect PCM to breakout box. Disconnect hose from EGR valve. Connect EGR vacuum hose to vacuum gauge. Start engine and allow to idle. Connect test pin No. 47 (EVR) at breakout box to chassis ground. If vacuum gauge reading is 4 in. Hg or more, replace PCM and repeat QUICK TEST. If vacuum gauge is less than 4 in. Hg, replace EVR solenoid. Clear PCM memory and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 169) to step 180). No test procedures have been omitted.
  90. Step 180) Continuous Memory DTC P0400  This DTC indicates EGR system malfunction during vehicle operation. Possible causes are as follows:
    • Restriction in EGR vacuum circuit.
    • EGR system fault.

    Ensure all DTCs are recorded. Clear PCM memory. Drive vehicle 5 miles. Perform KOEO and KOER SELF-TEST . If DTC P0400 is present in KOEO or KOER, go to step 130). If DTC is present in continuous memory only, remove and inspect EGR valve and intake manifold. Repair as necessary. If DTC P0400 is not present, fault is intermittent and cannot be duplicated at this time. Go to CIRCUIT TEST Z.

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