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Test HH: Exhaust Gas RECIRCULATION System Module: Testing

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION  table of fault code setting condition.
FAULT CODE SETTING CONDITION

Fault Code KOEO KOER Continuous Memory
P0401      HH70
P0402    HH20  HH20
P0403  HH10  HH10  HH120
P0405  HH1  HH1  HH1
P0406  HH10  HH10  HH10
P1400  HH1  HH1  HH1
P1401  HH10  HH10  HH10
P1406    HH60  HH60
P1408    HH71  
P1409  HH110  HH110  HH120

  1. 1) For KOEO, KOER & Continuous Memory DTC P0405 & P1400: Determine Present DPFEGR PID Voltage

    DTC P0405 and P1400 indicates EGR MONITOR failed due to average voltage to PCM dropping below minimum calibrated limit of less than .2 volt. Possible causes for this fault are:
    • DPFEGR Circuit Shorted To GND Or SIG RTN Circuit
    • Faulty DPFEGR Sensor
    • VREF Circuit Shorted To GND Or SIG RTN Circuit
    • Faulty PCM

    Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. If DPFEGR PID voltage is less than .2 volt, fault is currently present. Go to next step. If voltage is .2 volt or more, fault is intermittent. Go to step  5).

  2. 2) Attempt To Induce Opposite DPFEGR Sensor Voltage

    Turn ignition switch to OFF position. Disconnect ESM harness connector. Turn ignition switch to ON position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. If PID voltage is 4-6 volts, replace DPFEGR sensor. If PID voltage is not 4-6 volts, go to next step.

  3. 3) Check VREF And SIG RTN Circuits For Open In Harness To DPFEGR Sensor

    Using a DVOM, measure voltage between SIG RTN and VREF circuits at ESM harness connector. See Figure. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to TEST C, step 1) .

  4. 4) Check DPFEGR Circuit For Short To Ground & SIG RTN In Harness

    Disconnect scan tool from Data Link Connector (DLC). Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between DPFEGR circuit, and SIG RTN circuit at PCM harness connector, and negative battery terminal. See PCM CONNECTOR IDENTIFICATION and Figure. If both resistance measurements are more than 10 k/ohms, replace PCM. If either resistance measurement is 10 k/ohms or less, repair short to ground or SIG RTN in DPFEGR circuit.

  5. 5) Perform Wiggle Test On DPFEGR Sensor (On The ESM) & Circuit While Monitoring DPFEGR PID For A Sudden Change

    Ensure ignition switch is in ON position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Observe DPFEGR PID voltage reading for change while tapping lightly on DPFEGR sensor, and shaking and bending DPFEGR sensor wiring harness and connector to simulate road shock. A sudden change in DPFEGR PID voltage reading indicates a fault. If fault is indicated, isolate and repair as necessary. If no fault is indicated, go to TEST Z, step 1) .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 5) to step 10). No test procedures have been omitted.

  6. 10) For KOEO, KOER & Continuous Memory DTC P0403, P0406, P1401: Determine Present DPFEGR PID Voltage

    DTC P0406 and P1401 indicate EGR MONITOR failed due to average voltage to PCM exceeding maximum calibrated limit of 4.5 volts. Possible causes for this fault are:
    • Open In DPFEGR Or SIG RTN Circuit
    • VREF Or DPFEGR Circuit Shorted To PWR
    • Faulty DPFEGR Sensor
    • Faulty PCM

    Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. If DPFEGR PID voltage is more than 4 volts, fault is currently present. Go to next step. If DPFEGR PID voltage is 4 volts or less, fault is intermittent. Go to step  19).

  7. 11) Check DPFEGR Circuit For Short To PWR

    Turn ignition switch to OFF position. Disconnect ESM harness connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and DPFEGR circuit at ESM harness connector. See Figure. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, go to step  13).

  8. 12) Check DPFEGR Circuit For Short To PWR In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and DPFEGR circuit at PCM harness connector. See PCM CONNECTOR IDENTIFICATION and Figure. If voltage is more than 10.5 volts, repair short to PWR in DPFEGR circuit. If voltage is 10.5 volts or less, replace faulty PCM.

  9. 13) Induce Opposite DPFEGR Sensor Voltage

    Turn ignition switch to OFF position. Connect a jumper wire between DPFEGR and SIG RTN circuits at ESM harness connector. Turn ignition switch to ON position.
    NOTE: If a scan tool communication concern exists, remove jumper wire and go to step  18).

    Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. If DPFEGR PID voltage reading is .05 volt or more, disconnect jumper wire and go to step  16). If DPFEGR PID voltage reading is less than .05 volt, disconnect jumper wire and go to next step.

  10. 14) Check VREF Voltage To DPFEGR Sensor

    Turn ignition switch to ON position. Using a DVOM, measure voltage between SIG RTN and VREF circuits at ESM harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to TEST C, step 1) .

  11. 15) Check DPFEGR Circuit For Short To VREF In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between DPFEGR and VREF circuits at PCM harness connector (both VREF circuits on 150-pin PCM). See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is more than 10 k/ohms, replace DPFEGR sensor. If resistance is 10 k/ohms or less, repair short between DPFEGR and VREF circuits.

  12. 16) Check DPFEGR Circuit For Open In Harness

    Turn ignition switch to OFF position. Ensure DPFEGR sensor is disconnected. Disconnect PCM connector(s). Using a DVOM, measure resistance of DPFEGR circuit between PCM harness connector and ESM harness connector. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in DPFEGR circuit.

  13. 17) Check SIG RTN Circuit For Open In Harness

    Using a DVOM, measure resistance of SIG RTN circuit between PCM harness connector and ESM harness connector. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in SIG RTN circuit.

  14. 18) Check DPFEGR Circuit For Short To VREF In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between DPFEGR and VREF circuits at PCM harness connector (both VREF circuits on 150-pin PCM). See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short between DPFEGR and VREF circuits.

  15. 19) Complete A Wiggle Test On DPFEGR Sensor (On The ESM) & Circuit While Monitoring DPFEGR PID For A Sudden Change

    Turn ignition switch to ON position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Observe DPFEGR PID value for a sudden change while tapping lightly on DPFEGR sensor, and shaking and bending DPFEGR sensor wiring harness and connector to simulate road shock. A sudden change in DPFEGR PID value indicates a fault. If fault is indicated, isolate and repair as necessary. If no fault is indicated, go to TEST Z, step 1) .
    16. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  16. 20) For KOER & Continuous Memory Only DTC P0402: Check For EGR Flow At Idle With EGR Vacuum Hose Disconnected
    If DTC P1405 was output during Continuous Memory self-test, go directly to step  50) to diagnose present fault. DTC P0402 indicates EGR MONITOR failed due to PCM detecting EGR signal at idle is more than at KOEO by a calibrated amount of .5 volt. Possible causes for this fault are:
    • EGR Valve Stuck Open
    • EGR Vacuum Regulator (VR) Solenoid Vent Plugged
    • EGR Tube Plugged
    • DPFEGR Sensor Slow To Respond
    • Faulty DPFEGR Sensor
    • Pinched, Plugged, Damaged Or Improperly Connected Vacuum Hose
    • EGRVR Circuit Shorted To Ground
    • EGRVR Circuit Shorted To VREF Circuit
    • Faulty EGRVR Solenoid
    • Faulty PCM

    Disconnect and plug EGR valve vacuum hose. Perform KOER ON-DEMAND SELF-TEST . If KOER DTC P0402 is present, KOER self-test is unable to be performed, engine stalls or will not start, Turn ignition switch to OFF position. Inspect pressure hoses first for damage and pinching. If okay, remove ESM and inspect the EGR valve for signs of contamination, unusual wear, carbon deposits, binding and other damage. Repair as necessary. If DTC P0402 is not present, engine starts and does not stall, reconnect EGR valve vacuum hose and go to next step.

  17. 21) Check For EGR Flow At Idle With EGR Vacuum Hose Connected

    Ensure EGR valve vacuum hose is reconnected. Perform KOER ON-DEMAND SELF-TEST . If DTC P0402 is present, engine stalls or will not start, there may be EGR flow at idle. There is possible EGR flow at idle, go to step  23). If DTC P0402 is not present, engine starts and does not stall, fault is intermittent. Check vacuum hoses for pinching and icing. Repair as necessary and retest. If vacuum hoses are okay, go to step  30).

  18. 23) Check DPFEGR Sensor Output By Applying Vacuum With Hand Pump

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect vacuum hose at DPFEGR sensor on the ESM (downstream hose to intake manifold). Connect a hand vacuum pump to the downstream connection on the ESM. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Read the following DPFEGR PID values with ignition switch in ON position:
    • DO NOT apply vacuum to sensor. Record DPFEGR PID value. DPFEGR PID value should be .25-1.30 volts.
    • Using vacuum pump, apply 8-9 in. Hg (27-30 kPa) for a few seconds. DPFEGR PID value should increase to more than 4 volts.
    • Quickly release vacuum. DPFEGR PID value should drop to less than 1.5 volts within 3 seconds of releasing vacuum.

    If any DPFEGR PID values are not as specified, replace DPFEGR sensor. If all DPFEGR PID values are as specified, reconnect DPFEGR sensor and go to next step.

    19. NOTE: EGR valve requires more than 1.6 in. Hg (5.4 kPa) of vacuum to begin to open. If vacuum reading stays at more than 1.6 in. Hg (5.4 kPa) after EGRVR solenoid connector is disconnected, this indicates a mechanical fault in EGRVR solenoid.

  19. 24) Check For EGR Flow At Idle With EGR Vacuum Regulator Solenoid Connector Off
    Disconnect EGR valve vacuum hose and connect vacuum gauge to hose. Start engine and allow to idle. While observing vacuum gauge, disconnect EGRVR solenoid harness connector. If vacuum gauge measurement stays at more than 1.6 in. Hg (5.4 kPa), go to next step. If vacuum gauge measurement is 1.6 in. Hg (5.4 kPa) or less, go to step  26).
    20. NOTE: A plugged EGRVR solenoid vent will not allow EGR vacuum to vent to atmosphere.

  20. 25) Inspect EGR Vacuum Regulator Solenoid Vent For Plugging
    Turn ignition switch to OFF position. Disconnect EGRVR solenoid vacuum hose. Carefully remove EGR vacuum regulator solenoid vent cap (if the locking tabs are damaged the filter function may be compromised). Remove EGRVR solenoid filter and check for blockage or icing. Plug EGRVR solenoid vacuum supply port to EGR. Connect a hand vacuum pump to the EGR vacuum regulator solenoid (vacuum source port) and apply 10-15 in. Hg (34-51 kPa). If vacuum holds or is slow to release, EGRVR solenoid vent may be plugged or restricted. Repair EGRVR solenoid as necessary. If unable to repair EGRVR solenoid, replace ESM. If vacuum releases (solenoid vent not plugged or restricted), replace ESM.

  21. 26) Measure EGR Vacuum Regulator Solenoid Coil Resistance

    Turn ignition switch to OFF position. Ensure EGRVR solenoid is disconnected. Using a DVOM, measure resistance between EGRVR solenoid terminals. If resistance is 30-36 ohms, go to next step. If resistance is not 30-36 ohms, replace ESM.

  22. 27) Check EGRVR Circuit For Short To Ground In Harness

    Disconnect scan tool from DLC. Disconnect PCM connector(s). Using a DVOM, measure resistance between negative battery terminal and EGRVR circuit at PCM harness connector. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in EGRVR circuit.

  23. 28) Check EGRVR Circuit For Short To VREF

    Using a DVOM, measure resistance between EGRVR and VREF circuits at PCM harness connector (both VREF circuits on 150-pin PCM). See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short between EGRVR and VREF circuits.
    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.

  24. 30) Check DPFEGR Sensor Output By Applying Vacuum With Hand Pump

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect pressure hose at DPFEGR sensor (downstream/intake manifold line). Connect hand vacuum pump to downstream connection at DPFEGR sensor (intake manifold side of sensor). Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Read the following DPFEGR PID values with ignition switch in ON position:
    • DO NOT apply vacuum to sensor. Record DPFEGR PID value. DPFEGR PID value should be .2-1.3 volts.
    • Using vacuum pump, apply 8-9 in. Hg (27-30 kPa) for a few seconds. DPFEGR PID value should increase to more than 4 volts.
    • Quickly release vacuum. DPFEGR PID value should drop to less than 1.5 volts within 3 seconds of releasing vacuum.

    If any DPFEGR PID values are not as specified, replace DPFEGR sensor. If all DPFEGR PID values are as specified, reconnect DPFEGR sensor and go to next step.

  25. 31) Check DPFEGR Sensor Voltage While Exercising EGR Valve

    Ensure DPFEGR sensor is connected. Turn ignition switch to ON position. Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. View DPFEGR PID and make note of voltage. Typical DPFEGR sensor voltage (ESM system) with no EGR flow is between 0.3 and 0.6 volts. Start engine and allow to idle. Observe DPFEGR PID at idle and compare to the key on engine off voltage. (A higher voltage at idle could be due to a non-seating EGR valve.) Using scan tool output state control function, apply just enough vacuum to EGR valve to open it 2-3 in. Hg (7-10 kPa) without stalling engine and release vacuum. Repeat several times while observing DPFEGR PID. DPFEGR PID voltage must increase as valve begins to open and return to initial value as vacuum is released. A slow to return voltage could be an indication of a binding or slow-closing EGR valve. Service or replace EGR valve as necessary. If DPFEGR PID quickly returns to initial voltage reading after releasing vacuum, go to step  33).
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 31) to step 33). No test procedures have been omitted.

  26. 33) Inspect EGR Vacuum Regulator Solenoid Vacuum Hose For Potential Plugging

    Inspect EGR vacuum hose for possible blockage or pinching. If EGR vacuum regulator solenoid vacuum hose is plugged, repair as necessary. If EGR vacuum regulator solenoid vacuum hose is okay, unable to duplicate or identify fault at this time. Go to TEST Z, step 1) .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 33) to step 50). No test procedures have been omitted.

  27. 50) Inspect Upstream Pressure Hose Connections

    Inspect upstream hose for disconnect or poor connection. If hose is off or poorly connected, repair as necessary. Perform DRIVE CYCLES . Ensure EGR MONITOR PROCEDURE is performed to verify repair. If hose is off okay, go to next step.
    28. NOTE: It is essential that the DPFEGR pressure hose used is the correct repair part and not a substitute.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 51) to step 53). No test procedures have been omitted.

  28. 51) Inspect Upstream Pressure Hose For Plugging
    Visually inspect upstream pressure hose routing. Hose must not be pinched or have dips in it where water could settle or freeze. Remove upstream pressure hose and carefully inspect for plugging, water or leaks. If there is a fault detected in the hose, repair or replace upstream pressure hose as necessary. Perform DRIVE CYCLES . Ensure EGR MONITOR PROCEDURE is performed to verify repair. If hose is okay, go to step  53).

  29. 53) Check DPFEGR Sensor Output By Applying Vacuum With Hand Pump

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect pressure hoses at DPFEGR sensor. Connect hand vacuum pump to downstream connection at DPFEGR sensor (intake manifold side or smaller diameter port). Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Read the following DPFEGR PID values with ignition switch in ON position:
    • DO NOT apply vacuum to sensor. Record DPFEGR PID value. DPFEGR PID value should be .2-1.3 volts.
    • Using vacuum pump, apply 8-9 in. Hg (27-30 kPa) for a few seconds. DPFEGR PID value should increase to more than 4 volts.
    • Quickly release vacuum. DPFEGR PID value should drop to less than 1.5 volts within 3 seconds of releasing vacuum.

    If any DPFEGR PID values are not as specified, replace DPFEGR sensor. Perform DRIVE CYCLES . Ensure EGR MONITOR PROCEDURE is performed to verify repair. If all DPFEGR PID values are as specified, unable to duplicate or identify fault at this time. Go to TEST Z, step 1) .

    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.

  30. 60) For KOER & Continuous Memory Only DTC P1406: Inspect Downstream Pressure Hose Connections

    While driving, the EGR monitor commands the EGR valve closed and checks the differential pressure across the EGR orifice. The test fails when the signal from the DPF EGR sensor continues to indicate EGR flow even after the EGR valve is commanded closed.
    • Downstream hose is disconnected.
    • Downstream hose is plugged (ice).
    • Plugged or damaged EGR tube.

    If the fault is currently present, DTC P1408 will be output in Key On Engine Running (KOER) Self-Test.

    Verify EGR valve is securely attached and exhaust gasses are not leaking from the sealing surface. Inspect downstream hose at DPFEGR sensor for disconnect or poor connection. If hose is off or poorly connected, repair as necessary. If hose is okay, go to next step.

  31. 61) Inspect Downstream Pressure Hose For Plugging

    Visually inspect downstream pressure hose routing. Hose must not be pinched or have dips in it where water can settle or freeze. Remove downstream pressure hose and carefully inspect for plugging, water, or leaks. If there is a fault detected in the hose, repair or replace as necessary. If hose is okay, go to step  63).
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 61) to step 63). No test procedures have been omitted.

  32. 63) Check EGR Sensor Output By Applying Vacuum With Hand Pump

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect pressure hoses at DPFEGR sensor. Connect hand vacuum pump to downstream connection at DPFEGR sensor (intake manifold side or smaller diameter port). Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Read the following DPFEGR PID values with ignition switch in ON position:
    • DO NOT apply vacuum to sensor. Record DPFEGR PID value. DPFEGR PID value should be .2-1.3 volts.
    • Using vacuum pump, apply 8-9 in. Hg (27-30 kPa) for a few seconds. DPFEGR PID value should increase to more than 4 volts.
    • Quickly release vacuum. DPFEGR PID value should drop to less than 1.5 volts within 3 seconds of releasing vacuum.

    If any DPFEGR PID values are not as specified, replace DPFEGR sensor. If all DPFEGR PID values are as specified, reconnect DPFEGR sensor. Unable to duplicate or identify fault at this time, go to TEST Z, step 1) .

    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.

  33. 70) For Continuous Memory Only DTC P0401: Run KOER Self-Test

    DTC P0401 indicates EGR MONITOR failed due to PCM detecting EGR flow is less than desired minimum while driving. Possible causes for this fault are:
    • Vacuum Supply
    • EGR Valve Stuck Closed
    • EGR Valve Leaks Vacuum
    • EGR Flow Path Restricted
    • EGRVR Circuit Shorted To PWR
    • VREF Circuit Open To DPFEGR Sensor
    • DPFEGR Sensor Downstream Or Upstream Hoses Disconnected, Reversed Or Restricted
    • VPWR Circuit Open To EGRVR Solenoid
    • Damaged EGR Orifice Tube
    • Faulty EGRVR Solenoid
    • Faulty PCM

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

  34. 71) For KOER Only DTC P1408: Retrieve Continuous Memory DTCS

    DTC P1408 indicates KOER self-test failed due to measured EGR flow falling below or exceeding required calibration. Possible causes are:
    • Vacuum Supply
    • EGR Valve Stuck Closed
    • EGR Valve Leaks Vacuum
    • EGR Flow Path Restricted
    • EGRVR Circuit Shorted To PWR
    • VREF Circuit Open To DPFEGR Sensor
    • DPFEGR Sensor Downstream Or Upstream Hoses Disconnected, Reversed Or Restricted
    • VPWR Circuit Open To EGRVR Solenoid
    • Damaged EGR Orifice Tube
    • Faulty EGRVR Solenoid
    • Faulty PCM
    NOTE: If any DTC other than DTC P1406 is present, service those DTCs after completing this test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .

    Retrieve all Continuous Memory DTCs. If DTC P1406 is present, go to step  60). If DTC P1406 is not present, go to next step.

  35. 72) Run KOER Self-Test While Monitoring EGR Vacuum

    Disconnect vacuum hose at EVR and T-in a vacuum gauge. Perform KOER ON-DEMAND SELF-TEST . Approximately 30 seconds into test, EGR flow will be requested for a few seconds. The vacuum at this time should show a brief deflection to near zero from a steady value of approximately 15 in. Hg, indicating a request for the valve to open. If the vacuum decreases briefly to near zero from a steady value during KOER Self-Test, the vacuum indicated is sufficient to open the EGR valve. Fault is unlikely to be in EGR vacuum control system. Turn ignition switch to OFF position, go to next step. If the vacuum does not decrease briefly to near zero from a steady value during KOER Self-Test, the vacuum indicated is insufficient to open the EGR valve. Turn ignition switch to OFF position, go to step  80).

  36. 73) Inspect DPFEGR Sensor Pressure Hoses

    Visually inspect both pressure hoses for proper connection at DPFEGR sensor and EGR valve assembly. Inspect both hoses for improper routing. Hoses should not be pinched or have dips where water could settle or freeze. Inspect both hoses for leaks and blockage. Inspect DPFEGR sensor for damage. If a fault is detected, repair pressure hoses as necessary. If a fault is not detected, go to next step.

  37. 74) Check DPFEGR Sensor Output By Applying Vacuum With Hand Pump

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect pressure hoses at DPFEGR sensor. Connect hand vacuum pump to downstream connection at DPFEGR sensor (intake manifold side or smaller diameter port). Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Read the following DPFEGR PID values with ignition switch in ON position:
    • DO NOT apply vacuum to sensor. Record DPFEGR PID value. DPFEGR PID value should be 0.2-0.8 volts.
    • Using vacuum pump, apply 8-9 in. Hg (27-30 kPa) for a few seconds. DPFEGR PID value should increase to more than 4 volts.
    • Quickly release vacuum. DPFEGR PID value should drop to less than 1.0 volts within 3 seconds of releasing vacuum.

    If any DPFEGR PID values are not as specified, replace DPFEGR sensor. If all DPFEGR PID values are as specified, reconnect DPFEGR sensor and go to step  85).

    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 74) to step 80). No test procedures have been omitted.

  38. 80) Check Vacuum Source And Vacuum Hoses To EGR Vacuum Regulator Solenoid

    Inspect vacuum hoses between EGRVR solenoid and EGR valve for leaks, restrictions, damage or incorrect routing. Repair as necessary. If hoses are okay, disconnect vacuum hoses at EGRVR solenoid. Connect vacuum gauge to EGRVR solenoid vacuum supply hose. Start engine and allow to idle. If vacuum gauge measurement is 15 in. Hg (51 kPa) or more at idle, go to next step. If vacuum gauge measurement is less than 15 in. Hg (51 kPa), isolate fault and repair as necessary.

  39. 81) Check VPWR Voltage To EGR Vacuum Regulator Solenoid

    Turn ignition switch to OFF position. Disconnect EGRVR solenoid (ESM connector). Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and VPWR circuit at EGRVR solenoid harness connector. See Figure. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.

  40. 82) Check EGR Vacuum Regulator Solenoid Resistance

    Turn ignition switch to OFF position. Using a DVOM, measure resistance between EGRVR solenoid connector terminals. If EGRVR solenoid resistance is 30-36 ohms, go to next step. If EGRVR solenoid resistance is not 30-36 ohms, replace ESM.

  41. 83) Check EGRVR Circuit For Short To PWR In Harness

    Ensure ignition switch is in OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and EGRVR circuit at PCM harness connector. See PCM CONNECTOR IDENTIFICATION . If voltage is one volt or less, go to next step. If voltage is more than one volt, repair short to PWR in EGRVR circuit.

  42. 84) Check EGRVR Circuit For Open In Harness

    Turn ignition switch to OFF position. Measure resistance of EGRVR circuit between PCM harness connector pin and ESM (vacuum regulator solenoid) harness connector. If resistance is less than 5 ohms, reconnect EGRVR solenoid and PCM harness connectors and go to next step. If resistance is 5 ohms or more, repair open in EGRVR circuit.

  43. 85) Check EGR Vacuum Regulator Solenoid Vacuum Output Capability By Grounding EGRVR Circuit

    Connect a tachometer to monitor engine RPM. Start engine. With engine at idle, jumper PCM EGRVR circuit to chassis ground. If engine speed is reduced/stallout with jumper in, replace PCM. If engine speed is not reduced/stallout with jumper in, replace ESM.

  44. 90) Inspect EGR System For An Intermittent Failure

    Turn ignition switch to OFF position. Visually inspect entire EGR system for deterioration or signs of intermittent failure. Repair as necessary. If no faults are found, go to next step.

  45. 91) Inspect DPFEGR Sensor Pressure Hoses

    Inspect both hoses for improper routing. Hoses should not be pinched or have dips where water could settle or freeze. Inspect both hoses for leaks and blockage. Inspect DPFEGR sensor for blockage or damage. Repair as necessary. If no faults are found, go to next step.

  46. 92) Check DPFEGR Sensor Output By Applying Vacuum With Hand Pump

    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Disconnect pressure hoses at DPFEGR sensor. Connect hand vacuum pump to downstream connection at DPFEGR sensor (intake manifold side or smaller diameter port). Using scan tool, access DPFEGR PID from PID/DATA MONITOR & RECORD menu. Read the following DPFEGR PID values with ignition switch in ON position:
    • DO NOT apply vacuum to sensor. Record DPFEGR PID value. DPFEGR PID value should be 0.2-1.3 volts.
    • Using vacuum pump, apply 8-9 in. Hg (27-30 kPa) for a few seconds. DPFEGR PID value should increase to more than 4 volts.
    • Quickly release vacuum. DPFEGR PID value should drop to less than 1.5 volts within 3 seconds of releasing vacuum.

    If any DPFEGR PID values are not as specified, replace DPFEGR sensor. If all DPFEGR PID values are as specified, reconnect DPFEGR sensor and go to next step.

  47. 93) Check EGR Valve Function By Applying Vacuum With Hand Pump

    Start engine and bring to idle. Using scan tool, access DPFEGR and RPM PIDs from PID/DATA MONITOR & RECORD menu. Using Output Test Mode function, slowly apply EGR and hold it for 10 seconds. If engine wants to stall, increase RPM with throttle to maintain a minimum of 800 RPM. Look for the following:
    • EGR valve starts opening by increasing DPFEGR PID voltage.
    • DPFEGR PID voltage increasing until EGR valve is fully open. DPFEGR PID should read 2.5 volts minimum with full vacuum applied.
    • DPFEGR PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source could be leaking.

    If the DPFEGR PID voltage indicates that the EGR valve is operating as described in this test, go to next step. If the DPFEGR PID voltage does not indicate that the EGR valve is operating as described in this test, replace ESM.

    48. NOTE: In cold climates, the EGR valve may temporarily freeze shut and thaw when the engine warms up causing the intermittent DTC.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 94) to step 100). No test procedures have been omitted.

  48. 94) Inspect EGR Vacuum Signal Supply For Intermittent Failure
    Tee a vacuum gauge into the vacuum hose at EGRVR valve. Start engine and allow to idle. Connect a jumper wire between EGRVR circuit and ground to activate the solenoid to full on (note that the vacuum reading will briefly drop as the EGRVR is turned ON and OFF). Observe vacuum gauge for an indication of a fault while lightly taping on the EGR vacuum regulator solenoid and wiggling the EGR vacuum regulator solenoid connector, vacuum lines and vehicle harness between the solenoid and PCM. A fault is indicated by a sudden drop in vacuum reading. If a fault is indicated, isolate fault and repair as necessary. If a fault is not indicated, unable to duplicate or identify fault at this time. Go to TEST Z, step 1) .
    49. NOTE: Diagnostic step 100) is performed when directed here from POOR FUEL ECONOMY symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG & GASOLINE article.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 100) to step 110). No test procedures have been omitted.

  49. 100) EGR Diagnosis By Symptom: Check For EGR Flow With EGR Vacuum Hose Disconnected And Plugged
    A POOR FUEL ECONOMY symptom has indicated possible EGR flow at idle with no EGR DTCs stored. Possible causes are:
    • EGR Valve Not Fully Seated
    • EGRVR Solenoid Vent Restricted
    • Faulty EGRVR Solenoid

    Perform KOER ON-DEMAND SELF-TEST and service any other DTCs that are present. If no other DTCs are present, disconnect and plug EGR valve vacuum supply hose. Leave scan tool connected to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access DPFEGR PID and record voltage reading (KOEO). Start engine, allow to idle and record DPFEGR PID voltage reading (KOER). Compare KOER DPFEGR PID voltage reading to KOEO DPFEGR PID voltage reading. An increase in voltage at idle indicates that DPFEGR sensor is sensing EGR flow. If KOER DPFEGR PID voltage reading is .15 volt or more than that of KOEO reading, DPFEGR sensor is sensing EGR flow and most likely cause is EGR valve. Remove the ESM and check EGR valve for contamination, wear, carbon deposits, binding or damage. Repair as necessary. If DPFEGR PID voltage reading at idle is within .15 volt of KOEO reading, this indicates a fault in EGR valve vacuum supply. Check EGR valve vacuum supply hoses, EGRVR solenoid vent and vent filter for restriction. If vacuum supply hoses, EGRVR solenoid vent and vent filter are okay, replace ESM.

  50. 110) For KOEO & KOER Only DTC P1409: Check EGR Vacuum Regulator Solenoid Resistance

    DTC P0403 and P1409 indicates self-test failed due to EGRVR circuit voltage reading too high or too low when compared to expected voltage range. EGR system must be enabled for test to be completed. Possible causes are:
    • EGRVR Circuit Open Or Shorted To VPWR Or GND
    • VPWR Circuit Open To EGRVR Solenoid
    • Faulty EGRVR Solenoid
    • Faulty PCM

    Turn ignition switch to OFF position. Disconnect EGRVR solenoid (ESM connector). Using a DVOM, measure resistance between EGRVR solenoid terminals. If resistance is 30-36 ohms, go to next step. If resistance is not 30-36 ohms, replace ESM.

  51. 111) Check VPWR Voltage To EGR Vacuum Regulator Solenoid

    Turn ignition switch to ON position. Using a DVOM, measure voltage between VPWR circuit at EGRVR solenoid (ESM) harness connector and negative battery terminal. See Figure. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.

  52. 112) Check EVR Circuit For Open In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance of EGRVR circuit between PCM harness connector and EGRVR solenoid (ESM) harness connector. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in EGRVR circuit.

  53. 113) Check EVR Circuit For Short To Power In Harness

    Turn ignition switch to ON position. Using a DVOM, measure voltage between EGRVR circuit at PCM harness connector and negative battery terminal. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in EGRVR circuit.

  54. 114) Check EVR Circuit For Short To Ground In Harness

    Turn ignition switch to OFF position. Using a DVOM, measure resistance between EGRVR and PWR GND circuits at PCM harness connector. If resistance is 10 k/ohms or less, repair short between circuits. If resistance is more than 10 k/ohms, replace PCM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 114) to step 120). No test procedures have been omitted.
    55. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  55. 120) For Continuous Memory Only DTC P0403 & P1409: Wiggle EGR Vacuum Regulator Solenoid While Monitoring VPWR
    If DTC P1409 was output during KOEO or KOER self-test, go directly to step  110) to diagnose present fault. DTC P1409 indicates self-test failed due to EGRVR circuit voltage reading too high or too low when compared to expected voltage range. Possible causes are:
    • EGRVR Circuit Open Or Shorted To VPWR Or GND
    • VPWR Circuit Open To EGRVR Solenoid
    • Faulty EGRVR Solenoid
    • Faulty PCM

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage between PCM harness connector EGRVR and PWR GND terminals. See PCM CONNECTOR IDENTIFICATION . Voltage should be more than 10.5 volts. Observe DVOM for indication of fault while tapping lightly on EGRVR solenoid, and wiggling EGRVR solenoid wiring harness and connector to simulate road shock. Fault is indicated by a sudden drop in voltage reading. If fault is indicated, isolate and repair as necessary. If no faults are indicated, unable to duplicate or identify fault at this time. Go to TEST Z, step 1) .

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