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Circuit Test B10

NOTE: Perform this test when Service Code 31, 32, 33, 34, 35, or 84 is displayed during QUICK TESTS or when directed here by other test procedures.
Fig 1: Pressure Feedback EGR (PFE) & EGR Valve Regulator (EVR) Circuits
G6029
PFE SENSOR SPECIFICATIONS

Pressure psi/in. Hg (kPa) Voltage
1.82 PSI (12.5) 4.75
1.36 psi (9.42) 4.38
0.91 psi (6.25) 4.00
0.46 psi (3.17) 3.63
0 (0) 3.25
5 in. Hg (-17) 1.22
7.4 in. Hg (-25) 0.25
  1. Code 31: Generate Code 35. Code 31 indicates the PFE sensor signal is less than the Self-Test minimum of 0.2 volt. Turn key off. Disconnect PFE harness at sensor. Install a jumper wire between VREF and PFE SIGNAL at sensor connector. Perform KOEO SELF-TEST. Check for Code 35. Ignore all other codes at this time. If no codes are displayed, immediately remove jumper wire and go directly to step 4). If Code 35 is displayed, remove jumper wire and replace PFE sensor. Repeat QUICK TEST. If Code 35 is not displayed, go to next step.
  2. Measuring VREF to SIG RTN Voltage. With key off and PFE harness disconnected, set DVOM on 20-volt scale. With KOEO, measure voltage at PFE connector between VREF and SIG RTN. If reading is less than 4 volts or more than 6 volts, go to CIRCUIT TEST A3 , step 1). If reading is between 4 and 6 volts, go to next step.
  3. PFE Signal Continuity. With key off and PFE harness disconnected, set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between PFE SIGNAL at connector and test pin No. 27. If reading is 5 ohms or more, repair faulty circuit. Connect PFE sensor and remove breakout box. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
  4. PFE Signal Circuit Resistance. With key off and PFE harness disconnected, install breakout box leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between ground and PFE signal at connector. Measure resistance between PFE signal at connector and test pin No. 46. If either reading is less than 10K ohms, repair short circuit. Connect PFE and remove breakout box. Repeat QUICK TEST. If both readings are 10K ohms or more, replace ECA. Connect PFE and remove breakout box. Repeat QUICK TEST.
  5. Code 35: Generate Code 31. Code 35 indicates the PFE sensor signal is greater than the Self-Test maximum of 4.8 volts. Turn key off and disconnect PFE harness at sensor. Inspect for and repair any damaged wiring. Perform KOEO SELF-TEST. Check for Code 31. Ignore all other codes at this time. If Code 31 is not displayed, go to step 7). If Code 31 is displayed, go to next step.
  6. Measuring VREF to SIG RTN Voltage. Refer to wiring diagram in CIRCUIT TEST B10 . With key off and PFE harness disconnected, set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage at PFE connector between VREF and SIG RTN. If reading is between 4 and 6 volts, replace PFE sensor. Repeat QUICK TEST. If reading is less than 4 volts or more than 6 volts, go to CIRCUIT TEST A3 , step 1).
  7. Checking PFE Circuit For Shorts. With key off and PFE harness disconnected, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between test pin No. 27 and test pins No. 26, 37 and 57. If either reading is less than 10K ohms, repair short. Connect PFE and remove breakout box. Repeat QUICK TEST. If both readings are 10K ohms or more, replace ECA. Connect PFE and remove breakout box. Repeat QUICK TEST.
  8. Code 34: PFE Sensor Out Of Range. Code 34 indicates that PFE sensor is out of Self-Test range of 2.6-4.2 volts and that PFE sensor is probably faulty. The PFE system can detect lack of pressure in exhaust system. An efficient garage exhaust ventilation system, installed during KOEO SELF-TEST may cause PFE sensor to generate Code 34. Remove exhaust ventilation system and retest. If Code 34 is not displayed, service other codes displayed during KOEO SELF-TEST. If none are displayed, continue with QUICK TEST. If Code 34 is displayed, go to next step.
  9. Inspecting Supply to PFE Sensor. Remove pressure feed tube from PFE sensor. Inspect complete tube, including PFE inlet for blockage. If blockage is found, repair as necessary. Repeat QUICK TEST. If no blockage is found, go to next step.
  10. Measuring VREF to SIG RTN Voltage. Turn key off and disconnect PFE sensor. Inspect for and repair any damaged wiring. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage at PFE connector between VREF and SIG RTN. If reading is between 4 and 6 volts, replace PFE sensor. Repeat QUICK TEST. If reading is less than 4 volts or more than 6 volts, go to CIRCUIT TEST A3 , step 1).
  11. Code 84: Measure EVR Solenoid Resistance. Code 84 indicates a failure in EVR solenoid circuit. Turn key off. Set DVOM on 200-ohm scale. Disconnect EVR solenoid connector and measure solenoid resistance. If reading is less than 30 ohms or more than 70 ohms, replace EVR solenoid assembly. Repeat QUICK TEST. If reading is between 30 and 70 ohms, go to next step.
  12. Checking VPWR at EVR Solenoid. With KOEO and EVR solenoid disconnected from harness, set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between negative battery terminal and VPWR circuit at EVR solenoid connector. If reading is less than 10.5 volts, repair VPWR open circuit. Repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.
  13. Checking Continuity of EVR Circuit. Turn key off and disconnect EVR solenoid from harness. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 33 at the breakout box and EVR signal at the EVR solenoid harness. If reading is 5 ohms or more, repair open circuit. Connect EVR solenoid and remove breakout box. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
  14. Checking EVR Circuit For Ground Shorts. Turn key off. Install breakout box, leaving ECA disconnected. Disconnect EVR solenoid. Set DVOM on 200K-ohm scale. Measure resistance between test pin No. 33 and test pins No. 37, 57, 40, and 60 at the breakout box. If any reading is less than 10K ohms, repair short circuit. Remove breakout box. Connect ECA and EVR solenoid. Repeat QUICK TEST. If code is repeated, replace ECA. If all readings are 10K ohms or more, replace ECA. Remove breakout box. Connect ECA and EVR solenoid. Repeat QUICK TEST.
  15. Code 32: Verify Engine Running Codes. Code 32 indicates EGR valve is not fully seated. Possible causes for this fault are obstructed vacuum line, contaminated EVR filter, faulty EGR valve or faulty EVR solenoid. The PFE system can detect a lack of pressure in exhaust system. An efficient garage exhaust ventilation system, installed during KOER SELF-TEST may cause PFE sensor to generate Code 32. Temporarily remove exhaust ventilation system and retest. If Code 32 is not displayed, service other codes displayed during KOER SELF-TEST. If none, continue with QUICK TEST. If Code 32 is displayed, go to next step.
  16. Code 31: Separating EVR From PFE. Code 31 indicates PFE sensor signal is less than Self-Test minimum. Turn key off. Disconnect and plug EGR valve vacuum hose. Perform KOER SELF-TEST. If Codes 31 or 32 are present, go to next step. If not, go to step 18).
  17. Checking PFE Supply Tube for Blockage. With key off, check PFE sensor supply tube for blockage or leaks. If these faults are found, repair as necessary. Connect all lines and repeat QUICK TEST. If no faults are found, service exhaust gas recirculation system.
  18. EVR Filter Inspection. Turn key off. Remove and inspect EVR filter for contamination. A blocked filter will cause vacuum to be applied to EGR valve prematurely. If filter is contaminated, replace filter. Connect all lines and repeat QUICK TEST. If filter is not contaminated, replace EVR solenoid. Repeat QUICK TEST.
  19. Codes 34 or 35: Check for Excessive Backpressure. Codes 34 and 35 in KOER SELF-TEST indicate excessive exhaust backpressure. There are 2 possible causes: the exhaust system is blocked, or faulty PFE sensor. Turn key off. Substitute known good PFE sensor in place of original. Repeat KOER SELF-TEST. If Code 34 or 35 is not displayed, replace PFE sensor. Repeat QUICK TEST. If Code 34 or 35 is displayed, check exhaust system for restrictions.
  20. Code 33: Verify Vacuum at EGR Valve. Code 33 indicates PFE sensor input did not change after EVR solenoid received signal from ECA to open the EGR valve. Possible causes for this fault are as follows:
    • Vacuum hose leaks.
    • Obstructed vacuum hose.
    • Faulty EVR solenoid.
    • Faulty PFE sensor.
    • Faulty EGR valve.

    Turn key off and wait 10 seconds. Using a vacuum "T", connect vacuum gauge at EGR valve. Perform KOER SELF-TEST while observing vacuum gauge. Disregard code output. If vacuum reading is greater than one in. Hg, go to step 26). If vacuum reading is one in. Hg or less, go to next step.

  21. Vacuum Supply Hose Inspection. With key off, check vacuum hose from EVR solenoid to EGR valve and from vacuum source to EVR solenoid for loose connections, obstructions, cracks, etc. If vacuum hoses are damaged, repair or replace as necessary. Repeat QUICK TEST. If hoses are okay, go to next step or step No. 24 (all others).
  22. Supply Hose to EVR Verification. Turn key off and wait 10 seconds. Attach vacuum gauge to supply line between throttle body and EVR solenoid. Start and run engine at 2000 RPM. If vacuum reading is greater than 10 in. Hg, go to next step. If vacuum reading is less than 10 in. Hg, replace vacuum line to EVR, remove vacuum gauge and rerun QUICK TEST.
  23. Checking PCV Valve for Operation. With key off, disconnect vacuum hose at PCV valve from EVR solenoid. Connect vacuum pump to PCV valve. Slowly apply 10 in. Hg vacuum. If PCV valve opens and does not leak down, remove vacuum gauge, reconnect valve and go to step 25). If PCV valve does not open, service or replace PCV valve.
  24. Vacuum Supply to EVR Verification. Turn key off and wait 10 seconds. Attach vacuum gauge to source line from manifold. Start engine and run at idle. If vacuum is present, go to step 35). If no vacuum is present, replace vacuum hose to EVR solenoid and repeat QUICK TEST.
  25. Checking EGR Valve Operation. With KOEO, disconnect vacuum hose at EGR valve. Connect vacuum pump to EGR valve. While observing EGR valve, slowly apply 10 in. Hg vacuum. The EGR valve should begin to open with a very small amount of vacuum (1-1.5 in. Hg) and be fully open with about 4 in. Hg. If EGR opens freely and smoothly, check EVR solenoid filter for obstructions. If filter is okay, replace EVR solenoid and rerun QUICK TEST. If EGR valve does not open freely and smoothly, service or replace EGR valve.
  26. Checking PFE Sensor Supply Tube. With key off, check control pressure input tube to PFE sensor for cracks, obstructions or faulty connections. If supply tube is faulty, repair as necessary. If supply tube is okay, go to next step.
  27. Substitute Known Good PFE Sensor. Turn key off and wait 10 seconds. Substitute known good PFE sensor in place of original. Rerun KOER SELF-TEST. If Code 33 is present, service or replace EGR valve as necessary. If Code 33 is not present, original PFE sensor was the cause of the original Code 33. Replace PFE sensor and rerun QUICK-TEST.
  28. Continuous Memory Code 31 or 35: Testing PFE Sensor. Code 31 or 35 indicates that PFE sensor signal was less than (Code 31) or greater than (Code 35) the Self-Test voltage sometime during vehicle operation. Using KOEO CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or diagnostic tester for indication of fault while performing the following steps. Connect a vacuum pump to PFE sensor and slowly apply 5 in. Hg vacuum to sensor. Slowly bleed vacuum off PFE sensor. Lightly tap on PFE sensor and wiggle PFE connector. If fault is indicated, disconnect harness and inspect connector. If connector and terminals are okay, replace PFE sensor. Repeat QUICK TEST. If no fault is indicated, go to next step.
  29. Checking Harness. Observe VOM or diagnostic tester for fault indication while grasping harness close to sensor connector, then wiggling, shaking or bending small sections of harness while working your way to firewall. Also wiggle, shake or bend harness from firewall to ECA. If fault is indicated, isolate fault and repair as necessary. Repeat QUICK TEST. If fault is not indicated, go to next step.
  30. Checking ECA and Harness Connectors. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and terminals for damage. If connector and terminals are damaged, repair as necessary. Repeat QUICK TEST. If connector and terminals are okay, fault is intermittent and cannot be duplicated at this time.
  31. Continuous Memory Code 34: Checking PFE Supply Tube for Blockage. Code 34 indicates that the PFE sensor was restricted sometime during vehicle operation. Turn key off. Remove PFE sensor and inspect sensor supply inlet for liquids or any type of blockage. Inspect PFE supply tube at EGR valve base for liquids or blockage. If supply tube is blocked, clean or service as necessary. Repeat QUICK TEST. If supply tube is not blocked, fault is intermittent and cannot be duplicated at this time.
  32. Continuous Memory Code 32: Check EGR Valve Operation. Code 32 indicates that the EGR valve did not seat itself fully sometime during vehicle operation. Turn key off. Connect vacuum pump to EGR valve and apply 10 in. Hg of vacuum. While observing EGR valve, release vacuum, and repeat step if necessary. If EGR valve does not operate smoothly, service or replace EGR valve. If EGR valve works smoothly, go to next step.
  33. Vacuum Line Inspection. Inspect EGR valve vacuum supply line, from EVR solenoid to EGR valve for kinks or obstructions. If vacuum supply line is blocked, repair as necessary. Repeat QUICK TEST. If vacuum supply line is okay, go to next step.
  34. EVR Solenoid Filter Inspection. Carefully check EVR filter for contamination or obstructions. If EVR filter is contaminated, replace filter and repeat QUICK TEST. If EVR filter is not contaminated, fault is intermittent and cannot be duplicated at this time. Continuous Memory Code 32 testing is complete.
  35. Continuous Memory Code 33: Checking EGR Valve Operation. Code 33 indicates that EGR valve intermittently did not open during vehicle operation. Turn key off. Connect a vacuum pump to EGR valve. While observing EGR valve, slowly apply 10 in. Hg of vacuum. EGR valve should begin to open at 1-1.5 in. Hg and be fully open at 4 in. Hg of vacuum. If EGR valve does not move freely and smoothly, service exhaust gas recirculation system. If EGR valve moves freely and smoothly, go to next step.
  36. EVR Harness Test. With key off, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA to box. Enter OUTPUT STATE CHECK. Set DVOM on 20 volt scale. Connect DVOM negative test lead to test pin No. 40 at breakout box and DVOM positive test lead on test pin No. 33. Move throttle valve to indicate 10.5 volts or more and maintain position. While observing DVOM, grasp harness closest to EVR connector. Wiggle, shake or bend small sections of harness while working your way to firewall. Lightly tap EVR solenoid to simulate road vibration. If DVOM reads 10.5 volts or less, isolate fault and repair as necessary. Repeat QUICK TEST. If DVOM reads 10.5 volts or more, fault cannot be duplicated at this time. Continuous Memory Code 33 testing is complete.
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