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Diagnostic Aids

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

Fig 1: Identifying EGR System Circuits & Connector Terminals
G96C09577Courtesy of FORD MOTOR CO.
TEST DIRECTORY

DTC Action
P0400 Go To Step 50)
P0470 Or P1195 Go To Step 1)
P1402 Go To Step 40)
P0404 Go To Step 20)
P1487 Go To Step 10)
  1. 1) DTC P0470 Or P1195: EGR Boost Sensor Failure  DTC P0470 or P1195 indicates a failure in the EGR boost sensor circuit. Possible causes are as follows:
    • Damaged EGR boost sensor.
    • Faulty solenoid.
    • Poor harness connection.
    • Damaged hose.
    • Open or short circuit in harness.
    • Faulty PCM.

    Inspect harness connections at EGR boost sensor and EGR boost check solenoid. Check hose connections at EGR boost sensor and EGR boost check solenoid. Repair any faulty connections as needed. If connections are okay, go to next step.

  2. 2) Test EGR Boost Check Solenoid  Turn ignition off. Connect scan tester to OBD-II DLC. Turn ignition on. Using scan tool, Enter SIMULATION TEST and access EGR CHK PID. Turn dial to cycle EGR CHK solenoid at 75%. Run test. If EGR boost check solenoid clicks during test, go to next step. If EGR boost check solenoid does not click during test, go to step 10).
  3. 3) Check VREF At EGR Boost Sensor  Turn ignition off. Disconnect EGR boost sensor harness connector. Turn ignition on. Measure voltage between VREF and SIG RTN at EGR boost sensor harness connector. If voltage is approximately 5 volts, go to next step. If voltage is not approximately 5 volts, go to CIRCUIT TEST C .
  4. 4) Check EGRB Circuit Continuity  Turn ignition off. EGR boost sensor harness connector disconnected. Disconnect PCM harness connector, check for damaged or pushed out pins. Repair as necessary. Install breakout box (leave PCM disconnected). Measure resistance of the EGRB signal circuit between EGRB component harness connector and breakout box test pin EGRB. Measure resistance between of SIG RTN circuit between EGR boost sensor harness connector and breakout box test pin SIG RTN. If resistance is less than 10,000 ohms for each circuits, go to next step. If either resistance is greater than 10,000 ohms, repair open circuit. Reconnect all components and repeat QUICK TEST .
  5. 5) Check EGRB Circuit For Short  Turn ignition off. EGR boost sensor harness connector disconnected. Measure resistance between breakout box test pin EGRB and the following test pins; VPWR, VREF, SIG RTN and GND. If all resistance measurements are greater than 10,000 ohms, go to next step. If any resistance measurement is less than 10,000 ohms, repair short circuit. Reconnect all components and repeat QUICK TEST .
  6. 6) Check EGR Boost Sensor Output  Turn ignition off. Install breakout box (leave PCM disconnected). Reconnect EGR boost sensor harness connector. Disconnect EGR boost pressure hose from EGR boost sensor. Connect a vacuum pump to boost sensor. Turn ignition on. Measure voltage between breakout box test pin EGRB and test pin SIG RTN while applying vacuum to boost sensor. Compare voltage reading with EGRB OUTPUT VOLTAGE table. If output voltage does not agree with table, replace faulty EGR boost sensor. Restore all electrical connections and repeat QUICK TEST . If EGRB output voltage agrees with table, replace PCM and repeat QUICK TEST.
    EGRB OUTPUT VOLTAGE

    Boost Pressure (Vacuum) Voltage
    4.4 in. Hg 0.3
    11.8 in. Hg 1.6
    28.1 in. Hg 4.3
    31.0 in. Hg 4.8
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 20). No test procedures have been omitted.
  7. 20) DTC P0404: EGR Control Solenoid Fault  DTC P0404 indicates a failure in the EGR Control (EGRC) solenoid circuit. Possible causes for DTC P0404 are as follows:
    • Damaged EGRC solenoid.
    • Poor harness connection.
    • Damaged hose.
    • Open or short circuit in harness.
    • Faulty PCM.

    Inspect wiring harness and hose connections at EGRC solenoid. Repair any faulty connections as needed. If connections are okay, go to next step.

  8. 21) Test EGRC Solenoid  Turn ignition off. Connect scan tester to DLC. Turn ignition on. Using scan tool, enter SIMULATION TEST and access EGRC PID. Turn dial to cycle EGRC solenoid at 75%. Run test. If EGRC solenoid clicks during test, go to step 27). If EGRC solenoid does not click during test, go to next step.
  9. 22) Check VPWR At EGRC Solenoid  Turn ignition off. Disconnect EGRC solenoid harness connector. Turn ignition on. Measure voltage between VPWR circuit at EGRC solenoid 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, repair open VPWR circuit.
  10. 23) Check EGRC Solenoid Circuit Continuity  Turn ignition off. With scan tester connected to DLC, turn ignition on. Enter simulation test and access EGRC PID. Turn dial to cycle EGRC at 100%. Measure voltage between EGRC circuit at solenoid harness connector and battery negative terminal. If voltage switches from battery voltage, to zero volts and back to battery voltage, go to step 27). If voltage is steady at battery voltage, go to next step. If no voltage is measured, go to step 25).
  11. 24) Check EGRC Circuit For Short To Power  Turn ignition off. Disconnect EGRC solenoid harness connector. Install breakout box (leave PCM disconnected). Measure resistance between breakout box test pin EGRC and test pin VPWR. If resistance is greater than 10,000 ohms, go to step 26). If resistance is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
  12. 25) Check EGRC Circuit For Short To Ground  Turn ignition off. Disconnect EGRC solenoid harness connector. Install breakout box (leave PCM disconnected). Measure resistance between breakout box test pin EGRC and test pin No. 25 (GND). If resistance is greater than 10,000 ohms, go to next step. If resistance is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
  13. 26) Check For Open EGRC Circuit  Turn ignition off. Leave EGRC solenoid harness connector disconnected. Measure resistance between breakout box test pin EGRC and EGRC circuit at EGRC solenoid harness connector. If resistance is less than 10,000 ohms, go to next step. If resistance is 10,000 ohms or greater, repair open EGRC circuit and repeat QUICK TEST .
  14. 27) Check EGRC Solenoid  Turn ignition off. Remove EGRC solenoid from vehicle. Connect a vacuum hose to port "A". Blow into port "A". See Fig 2. Air should not pass through valve. Apply battery voltage and ground to EGRC solenoid. Blow air into port "A". Air should pass through valve to port "B" with battery voltage applied. If EGRC solenoid does not operate as specified, replace EGRC solenoid. Repeat QUICK TEST . If EGRC solenoid operates as specified, go to step 30).
    Fig 2: Testing EGR Control & Vent Solenoids
    G96G09579Courtesy of FORD MOTOR CO.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 27) to step 30). No test procedures have been omitted.
  15. 30) DTC P0404: EGR Vent Solenoid Fault  DTC P0404 indicates a malfunction in EGR Vent (EGRV) solenoid circuit. Possible causes are as follows:
    • Damaged EGRV solenoid.
    • Poor harness connection.
    • Misrouted or damaged vacuum hose.
    • Faulty PCM.
    • Damaged wiring harness.

    Inspect EGRV solenoid harness and vacuum hose connections. Repair as necessary. Repeat QUICK TEST . If hoses and harness appear to be in good condition, go to next step.

  16. 31) Check EGRV Solenoid  Turn ignition off. Connect scan tester to DLC. Turn ignition on. Enter simulation test and access EGRV PID. Turn dial on scan tool to cycle EGRV at 75% and run test. If a clicking can be heard from EGRV solenoid, go to step 37). If EGRV solenoid does not click, go to next step.
  17. 32) Check VREF At EGRV Solenoid  Turn ignition off. Disconnect EGR vent solenoid harness connector. Turn ignition on. Measure voltage between VPWR circuit at EGRV solenoid harness connector and negative battery terminal. If voltage is more than 10.5 , go to next step. If voltage is not 10.5 volts or less, repair open VPWR circuit.
  18. 33) Check EGRV Solenoid Circuit Continuity  Turn ignition off. Disconnect EGRV solenoid connector. With scan tester connected to DLC, turn ignition on. Enter simulation test and access EGRV PID. Turn dial to cycle EGRV at 100%. Measure voltage between EGRV circuit at solenoid harness connector and battery negative terminal. If voltage switches from battery voltage to zero volts and back to battery voltage, go to step 37). If voltage is steady at approximately battery voltage, go to next step. If no voltage is measured, go to step 35).
  19. 34) Check EGRV Circuit For Short To Power  Turn ignition off. EGRV solenoid harness connector disconnected. Install breakout box (leave PCM disconnected). Measure resistance between breakout box test pin EGRV and test pin VPWR. If resistance is greater than 10,000 ohms, go to step 36). If resistance is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
  20. 35) Check EGRV Circuit For Short To Ground  Turn ignition off. EGRV solenoid harness connector disconnected. Install breakout box (leave PCM disconnected). Measure resistance between breakout box test pin EGRV and test pin GND. If resistance is greater than 10,000 ohms, go to next step. If resistance is less than 10,000 ohms, repair short circuit and repeat QUICK TEST .
  21. 36) Check For Open EGRV Circuit  Turn ignition off. EGRV solenoid harness connector disconnected. Breakout box installed (PCM disconnected). Measure resistance between breakout box test pin EGRV and EGRV circuit at EGRV solenoid harness connector. If resistance is less than 10,000 ohms, go to next step. If resistance is 10,000 ohms or greater, repair open EGRV circuit and repeat QUICK TEST .
  22. 37) Check EGR Vent Solenoid  Turn ignition off. Remove EGR Vent (EGRV) solenoid from vehicle. Block off port "D". See Fig 2. Connect a vacuum hose to port "C" and attempt to blow through valve. Air should pass from port "C" to port "E". Apply battery voltage and ground to EGRV solenoid and blow air into port "C". Air should pass through valve with battery voltage applied. If EGRV solenoid does not operate as specified, replace EGRV solenoid. Restore electrical connections and repeat QUICK TEST . If EGRV solenoid operates as specified, fault may be intermittent. See CIRCUIT TEST Z , for intermittent diagnostic procedures.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 37) to step 40). No test procedures have been omitted.
  23. 40) DTC P1402: EVP Circuit Fault  DTC P1402 indicates a malfunction EGR Valve Position (EVP) sensor circuit. Possible causes are as follows:
    • Damaged EVP sensor.
    • Poor harness connection.
    • Damaged EGR valve.
    • Faulty PCM.
    • Damaged wiring harness.

    Turn ignition off. Disconnect EVP sensor harness connector. Turn ignition on. Using scan tester, access EGR PID. If EGR PID is between 0.2-4.8 volts, go to step 48). If PID is less than 0.2 volt, go to next step. If PID is greater than 4.8 volts, go to step 45).

  24. 41) Check VREF To EVP Sensor  Turn ignition off. Disconnect EVP sensor harness connector. Turn ignition on. Measure voltage between VREF and SIG RTN circuits at EVP sensor harness connector. If voltage is greater than 4.8 volts, go to next step. If voltage is 4.8 volts or less, go to CIRCUIT TEST C .
  25. 42) Simulate High EVP Signal  Turn ignition off. Disconnect EVP sensor harness connector. Connect a jumper wire between EVP signal circuit and VREF circuit at EVP sensor harness connector. Connect scan tester to OBD-II DLC. Turn ignition on. Access EGR PID. If EGR PID is greater than 4.8 volts, replace EVP sensor and repeat QUICK TEST . If EGR PID is less than 4.8 volts, remove jumper wire and go to next step.
  26. 43) Check EVP & SIG RTN Circuits  Turn ignition off. Disconnect EVP sensor harness connector. Disconnect PCM and check harness connector for damage. Install breakout box (leave PCM disconnected). Measure resistance between EVP circuit at EVP sensor harness connector and breakout box test pin EVP. Also, measure resistance between SIG RTN circuit at EVP sensor harness connector and breakout box test pin SIG RTN. If both resistance measurements are less than 5 ohms, go to next step. If either resistance measurement is greater than 5 ohms, repair open circuit in question and repeat QUICK TEST .
  27. 44) Check EVP Signal Short To Ground  Turn ignition off. Measure resistance between breakout box test pin EVP and the following test pins; SIG RTN and GND. If resistance is less than 10,000 ohms, repair short to ground condition in EVP circuit. If resistance reading is greater than 10,000 ohms, replace EVP sensor and repeat QUICK TEST . Restore all electrical connections and repeat QUICK TEST.
  28. 45) Simulate Low EVP Signal  Turn ignition off. Disconnect EVP sensor harness connector. Connect a jumper wire between EVP terminal and SIG RTN terminal at EVP sensor harness connector. Connect scan tester to DLC. Turn ignition on. Using scan tester, access EGR PID. If EGR PID is less than 0.2 volt, replace EVP sensor and repeat QUICK TEST . If EGR PID is greater than 0.2 volt, remove jumper wire and go to next step.
  29. 46) Check EVP & SIG RTN Circuits  Turn ignition off. Disconnect EVP sensor harness connector. Disconnect PCM and check harness connector for damage. Install breakout box (leave PCM disconnected). Measure resistance between EVP terminal at EVP sensor harness connector and breakout box test pin EVP. Measure resistance between SIG RTN terminal at EVP sensor harness connector and breakout box test pin SIG RTN. If both circuit resistance measurements are less than 5 ohms, go to next step. If either resistance measurement is greater than 5 ohms, repair open circuit and repeat QUICK TEST .
  30. 47) Check EVP Signal Short To VREF  Turn ignition off. Measure resistance between breakout box test pin EVP and test pin VREF. If resistance reading is less than 10,000 ohms, repair circuit short to VREF and repeat QUICK TEST . If resistance reading is greater than 10,000 ohms, replace EVP sensor and repeat QUICK TEST.
  31. 48) Check EGR Valve Function  Start engine and warm to normal operating temperature. Turn ignition off. Connect scan tester to OBD-II DLC. Connect a vacuum pump to EGR valve. Start engine. Access EGR PID. Observe EGR PID while applying vacuum to EGR valve. If engine stumbles or stalls and EGR PID increases, EGR system function properly at this time. See CIRCUIT TEST Z , for intermittent diagnostic procedures. If engine stumbles or stall but EGR PID remains constant, replace EVP sensor. If engine does not stumble or stall, remove EGR valve and repair or replace as necessary.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 48) to step 50). No test procedures have been omitted.
  32. 50) DTC P0400: EGR Flow Malfunction  DTC P0400 indicates EGR is not operating as within PCM guidelines. Possible causes are as follows:
    • Damaged or dirty EGR valve.
    • EGR boost sensor malfunction.
    • EGR boost check solenoid malfunction.
    • EVP sensor malfunction.
    • EGR control or vent solenoid malfunction.
    • EGR pipes clogged or leaking.
    • Damaged vacuum hose.

    Run QUICK TEST . If any DTCs other than P0400 are displayed, repair other DTCs first. If DTC P0400 returns, go to next step. If no other DTCs are displayed, go to next step.

  33. 51) Check Vacuum Hose  Check all vacuum hoses associated to EGR operation for proper routing and hose condition. Repair as necessary. Repeat QUICK TEST . If vacuum hoses are okay, go to next step.
  34. 52) Check EGR Boost Sensor Output  Turn ignition off. Ensure EGR boost sensor harness connector is connected. Install breakout box. Disconnect pressure hose from EGR boost sensor. Connect a vacuum pump to EGR boost sensor. Turn ignition on. While applying vacuum to EGR boost sensor, measure voltage between breakout box test pin EGRB and test pin SIG RTN. If voltage measurements agree with EGR BOOST SENSOR SPECIFICATION table, go to next step. If voltage is not as specified, replace EGR boost sensor and repeat QUICK TEST .
    EGR BOOST SENSOR SPECIFICATIONS

    Boost Pressure Voltage
    4.4 in. Hg (15 kPa) 0.3
    11.8 in. Hg (40 kPa) 1.55
    28.1 in. Hg (95 kPa) 4.3
  35. 53) Check EGR Valve Function  Start engine and warm to normal operating temperature. Turn ignition off. Connect scan tester to OBD-II DLC. Connect a vacuum pump to EGR valve. Start engine. Access EGR PID. Observe EGR PID while applying vacuum to EGR valve. If engine stumbles or stalls and EGR PID increases, go to next step. If engine stumbles or stalls but EGR PID remains constant, replace EVP sensor. If engine does not stumble or stall, remove EGR valve and repair or replace as necessary.
  36. 54) Clear DTCs  Erase DTCs from PCM memory. Drive car faster than 7 MPH with engine warm. Repeat QUICK TEST . If DTC P0400 returns, replace PCM. If DTC P0400 does not return, fault was intermittent. See CIRCUIT TEST Z , for intermittent diagnostic procedures.
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