LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 1996 >> Aerostar Van Window >> Repair and Diagnosis >> External Pages >> Different car >> Section 205 (Engine Controls - Tests W/Codes - 4.0L) >> Circuit Tests >> Circuit Test HX - Evaporative Emission (EVAP) Monitor & System >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different car, the 1996 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.

Perform this test when instructed during QUICK TEST  or if directed by other test procedures. This test is used to diagnose the following:

Fig 1: FTP Connector & Test Circuit
G96J01004
Fig 2: VMV Connector & Test Circuit
G96C01005
  1. Step 1) Continuous Memory DTC P0442 Or P1442  Turn ignition off. Ensure fuel fill cap is correctly installed. Ensure cap is not damaged or excessively worn. Service or replace as necessary and verify symptom is repaired. If fuel fill cap is okay, go to next step.
  2. Step 2) Leave ignition off. Check all fuel vapor hoses for damage or restrictions. Ensure hose connections are tight. Service or replace as necessary and verify symptom is repaired. If fuel vapor hoses are okay, go to step 61).
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 2) to step 6). No test procedures have been omitted.
  3. Step 6) Continuous Memory DTC P0443  Perform QUICK TEST . If DTC P0443 is present in Continuous Memory only, go to step 12). If DTC P0443 is present in KOEO or KOER SELF-TEST , go to next step.
  4. Step 7) DTC P0443: Check VPWR Circuit Voltage  Turn ignition off. Disconnect Vapor Management Valve (VMV) wiring harness connector. Turn ignition on. Measure voltage between VPWR terminal of VMV wiring harness connector and battery 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 and repeat QUICK TEST .
  5. Step 8) Check VMV Resistance  Turn ignition off. Leave VMV wiring harness connector disconnected. Measure resistance between CANP solenoid or VMV terminals. If resistance is 30-36 ohms, go to next step. If resistance is not as specified, replace VMV and repeat QUICK TEST .
  6. Step 9) Check VMV Circuit Continuity  Leave ignition off and VMV wiring harness connector disconnected. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 56 at breakout box and VMV terminal of VMV wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance 5 ohms or more, repair open circuit and repeat QUICK TEST .
  7. Step 10) Check Circuit For Short To PWR GND  Leave ignition off and VMV wiring harness connector disconnected. Disconnect scan tester from DLC (if applicable). Measure resistance between test pin No. 56 (VMV) and test pins No. 24 and 103. If each resistance is more than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair VMV circuit short to PWR GND circuit. Clear PCM memory and repeat QUICK TEST .
  8. Step 11) Leave ignition off and VMV disconnected. Turn ignition on. Measure voltage between breakout box test pin No. 56 and test pins No. 51 and 103. If voltage is greater than 10.5 volts, repair VMV circuit short to VPWR and repeat QUICK TEST . If voltage is 10.5 volts or less, replace PCM and repeat QUICK TEST .
  9. Step 12) Wiggle Test VMV & Harness  Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Using DVOM, measure resistance between test pin No. 56 (VMV) and test pins No. 71 and 97. Observe DVOM for indication of fault while shaking and bending VMV wiring harness and connector. A fault will be indicated by resistance measurement of less than 30 ohms or more than 36 ohms. Tap lightly on VMV to simulate road shock. If fault is indicated, isolate and repair as necessary. If no fault is indicated, see CIRCUIT TEST Z.
  10. Step 13) Continuous Memory DTC P0446  Turn ignition off. Remove fuel fill cap. Connect scan tester to DLC. Turn ignition on. Using scan tester, access FTP V PID. Record FTP T PID voltage. Install fuel fill cap to first click. If FTP T PID voltage is 2.37-2.87 volts, go to step 15). If FTP T PID voltage is not 2.37-2.87 volts, go to next step.
  11. Step 14) Check VREF At FTP Connector  Turn ignition off. Disconnect FTP wiring harness connector. Turn ignition on. Measure voltage between VREF terminal and SIG RTN terminal at wiring harness connector. If voltage is 4-6 volts, replace FTP sensor and repeat QUICK TEST . If voltage is not 4-6 volts, go to CIRCUIT TEST C.
  12. Step 15) Check Carbon Canister  Check for restrictions at carbon canister atmosphere vent port. Check for restrictions in purge air inlet tube (large diameter hose) between CV solenoid and atmosphere. Repair or replace as necessary. If no faults are found, go to next step.
  13. Step 16) Check CV Solenoid Filter Port  Disconnect purge air inlet tube (large diameter hose) from CV solenoid. If vehicle is not equipped with purge air inlet tube, go to next step. Locate opposite end of tube (in fuel filter housing). Drop a 3/8" ball bearing into tube. If ball bearing passes through tube, go to next step. If ball bearing does not pass through tube, service or replace tube as necessary and repeat QUICK TEST .
  14. Step 17) Check CV Solenoid Mechanical Operation  Remove CV solenoid hose. Connect vacuum pump to solenoid. Using vacuum pump, apply 16 in. Hg to solenoid. If vacuum is held for one minute, replace solenoid and repeat QUICK TEST . If vacuum is not held for one minute, go to next step.
  15. Step 18) DTC P0446  Turn ignition off. Connect scan tester to DLC. Turn ignition on. Using tester, access EVAPCVF PID. If scan tester indicates YES, go to next step. If scan tester does not indicate YES, go to step 21).
  16. Step 19) Check CV Solenoid Resistance  Turn ignition off. Disconnect CV solenoid wiring harness connector. Measure resistance between CV and VPWR terminal at solenoid. If resistance is less than 45 ohms, replace CV solenoid and repeat QUICK TEST . If resistance is 45 ohms or more, go to next step.
  17. Step 20) Check Circuit For Short To PWR GND  Leave ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 67 (CV) and test pins No. 51 and 103. If each resistance is more than 10,000 ohms, replace PCM and repeat QUICK TEST . If resistance is 10,000 ohms or less, repair CV circuit short to PWR GND circuit. Clear PCM memory and repeat QUICK TEST .
  18. Step 21) Wiggle Test CV Solenoid & Harness  Turn ignition on. Using scan tester, access EVAPCVF PID. Observe EVAPCVF PID for indication of fault while shaking and bending CV solenoid wiring harness and connector. A fault will be indicated by a change in EVAPCVF PID voltage. Tap lightly on CV solenoid to simulate road shock. If fault is indicated, isolate and repair as necessary. If no fault is indicated, go to CIRCUIT TEST Z.
  19. Step 22) DTC P0452  Turn ignition off. Connect scan tester to DLC. Check FTP wiring harness connector for damage or fuel contamination. Repair or replace if necessary. If connector is okay, go to next step.
  20. Step 23) Verify FTP Signal Voltage  Leave ignition off. Connect scan tester to DLC. Turn ignition on. Using scan tester, access FTP V PID. If FTP V PID is less than 0.22 volts, go to next step. If FTP V PID is 0.22 volts or more, go to step 27).
  21. Step 24) Induce Opposite FTP Signal  Leave ignition off. Disconnect FTP wiring harness connector. Connect jumper wire between FTP terminal and VREF terminal at connector. Turn ignition on. Using scan tester, access FTP V PID. If scan tester error occurs, go to next step. If FTP V PID is 4-6 volts, replace FTP and repeat QUICK TEST . If FTP V PID is not 4-6 volts, remove jumper wire and go to next step.
  22. Step 25) Check VREF At FTP Connector  Leave ignition off. Disconnect FTP wiring harness connector. Connect jumper wire between FTP terminal and VREF terminal at connector. Turn ignition on. Using scan tester, access FTP V PID. If scan tester error occurs, go to next step. If FTP V PID is 4-6 volts, replace FTP and repeat QUICK TEST . If FTP V PID is not 4-6 volts, remove jumper wire and go to next step.
  23. Step 26) Check Circuit For Short To PWR GND Or SIG RTN  Leave ignition off and FTP disconnected. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Disconnect scan tester from DLC. Measure resistance between test pin No. 62 (FTP) and test pins No. 51, 91 and 103. If each resistance more than 10,000 ohms, replace PCM, repeat QUICK TEST . If resistance is 10,000 ohms or less, repair FTP circuit short to SIG RTN or PWR GND circuit. Clear PCM memory and repeat QUICK TEST .
  24. Step 27) Wiggle Test CV Solenoid & Harness  Turn ignition on. Using scan tester, access FTP V PID. Observe FTP V PID for indication of fault while shaking and bending FTP sensor wiring harness and connector. A fault will be indicated by a change in FTP V PID voltage. Tap lightly on FTP sensor to simulate road shock. If fault is indicated, isolate and repair as necessary. If no fault is indicated, go to CIRCUIT TEST Z.
  25. Step 28) DTC P0453  Turn ignition off. Connect scan tester to DLC. Turn ignition on. Using tester, access FTP V PID. If FTP V PID more than 4.5 volts, go to next step. If FTP V PID 4.5 volts or less, go to step 37).
  26. Step 29) Check FTP Signal For Short To Power  Leave ignition off. Disconnect FTP wiring harness connector. Turn ignition on. Measure voltage between negative battery terminal and FTP terminal at wiring harness connector. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, go to step 31).
  27. Step 30) Check FTP Circuit For Short To VPWR  Leave FTP disconnected. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 62 (FTP) and test pins No. 51 and 103 at breakout box. If either voltage is less than 10.5 volts, replace PCM and repeat QUICK TEST . If all voltages are 10.5 volts or more, repair FTP circuit short to VPWR. Clear PCM memory and repeat QUICK TEST .
  28. Step 31) Induce Opposite FTP Signal  Turn ignition off. Leave FTP wiring harness connector disconnected. Connect jumper wire between FTP terminal and SIG RTN terminal at connector. Turn ignition on. Using scan tester, access FTP V PID. If scan tester error occurs, go to step 36). If FTP V PID is less than 0.1 volt, go to next step. If FTP V PID is 0.1 volts or more, go to step 34).
  29. Step 32) Check VREF At FTP Connector  Leave ignition off. Disconnect FTP wiring harness connector. Measure voltage between SIG RTN terminal and VREF terminal at 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.
  30. Step 33) Check FTP Circuit For Short To VREF  Leave ignition off and FTP disconnected. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Disconnect scan tester from DLC. Measure resistance between test pins No. 62 (FTP) and 90 (VREF) at breakout box. If resistance is more than 10,000 ohms, replace FTP sensor and repeat QUICK TEST . If resistance is 10,000 ohms or less, repair FTP circuit short to VREF. Clear PCM memory and repeat QUICK TEST .
  31. Step 34) Check FTP Circuit Continuity  Leave ignition off and FTP disconnected. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Disconnect scan tester from DLC. Measure resistance between test pin No. 62 (FTP) and FTP terminal at FTP wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in FTP circuit. Clear PCM memory and repeat QUICK TEST .
  32. Step 35) Check SIG RTN Circuit Continuity  Leave ignition off and FTP disconnected. Measure resistance between test pin No. 91 and SIG RTN terminal at FTP 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. Clear PCM memory and repeat QUICK TEST .
  33. Step 36) Check FTP Circuit For Short To VREF  Leave ignition off and FTP disconnected. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pins No. 62 (FTP) 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 FTP circuit short to VREF. Clear PCM memory and repeat QUICK TEST .
  34. Step 37) Wiggle Test CV Solenoid & Harness  Turn ignition on. Using scan tester, access FTP V PID. Observe FTP V PID for indication of fault while shaking and bending FTP sensor wiring harness and connector. A fault will be indicated by a change in FTP V PID voltage. Tap lightly on FTP sensor to simulate road shock. 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 37) to step 40). No test procedures have been omitted.
  35. Step 40) Continuous Memory P0455 Or P1455  Turn ignition off. Ensure fuel fill cap is correctly installed and in good condition. Check carbon canister for damage. Check fuel vapor hoses for correct routing. Check fuel tank and fill pipe for damage. Repair or replace as necessary and go to step 61). If no faults are present, go to next step.
  36. Step 41) Check System Pressure  Turn ignition off. Remove fuel fill cap. Disconnect and plug fuel vapor hose at VMV. Connect scan tester to DLC. Using scan tester, access Output Test Mode and select All Off mode. Turn ignition on. Using Evaporative Emission System Tester (Rotunda 134 00056), pressurize evaporative system at 14 in. Hg. (if evaporative emission system tester is not available, go to step 47). If system holds vacuum for 2 minutes, go to step 43). If system does not hold vacuum for 2 minutes, go to next step.
  37. Step 42) Leave ignition on and evaporative emission system pressurized. Using scan tester, access FTP V PID. If FTP V PID is 4.42-4.78 volts, go to next step. If voltage is not as specified, replace FTP sensor and go to step 61).
  38. Step 43) Leave ignition on and evaporative emission system pressurized. Close purge air inlet tube at CV solenoid port. If system does not hold vacuum for 2 minutes, go to step 45). If system holds vacuum for 2 minutes, go to next step.
  39. Step 44) Check FTP Signal For Short To Power  Leave ignition off. Disconnect CV solenoid wiring harness connector. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950). Connect PCM to breakout box. Turn ignition on. Measure voltage between negative battery terminal and VPWR terminal at CV solenoid wiring harness connector. If voltage is 10.5 volts or more, replace CV solenoid and go to step 61). If voltage is less than 10.5 volts, repair open in VPWR circuit and go to step 61).
  40. Step 45) Check For Leaks Using Ultra Sonic Leak Detector  Leave ignition on and CV solenoid wiring harness connector disconnected. Using ultra sonic earphones, pass probe over fuel vapor hoses and connections. If sudden audible change is detected (indicating leak), isolate and repair as necessary. If leak is not detected, release system pressure and go to next step.
  41. Step 46) Check Fuel Vapor Hose  Leave ignition on and CV solenoid wiring harness connector disconnected. Remove and plug fuel vapor hose from carbon canister at VMV. Using evaporative emission system tester, pressurize evaporative system at 14 in. Hg. When pressure stabilizes, remove plug from fuel vapor hose. If pressure drops immediately, install fuel fill cap and tighten to first click. Go to next step. If pressure does not drop immediately, isolate restriction in system and repair as necessary. Reconnect all components and go to step 61).
  42. Step 47) Check Intake Manifold Vacuum At VMV  Leave ignition off. Connect VMV wiring harness connector. Disconnect hoses from VMV at intake manifold. Start engine and allow to idle. Check for vacuum at intake manifold. If vacuum is present, go to next step. If vacuum is not present, isolate fault. Repair as necessary and go to step 61).
  43. Step 48) Check VMV Ability To Hold Vacuum  Leave ignition off. Connect vacuum pump to disconnected end of VMV hose. Using vacuum pump, apply 16 in. Hg. If vacuum bleeds off immediately, go to next step. If vacuum does not bleed off immediately, isolate hose restriction and repair as necessary. Go to step 61).
  44. Step 49) Check VMV  Turn ignition off. Reconnect VMV wiring harness connector. Disconnect VMV fuel vapor hose from intake manifold port at VMV. Attach vacuum pump with gauge to intake manifold port at VMV. Using vacuum pump, apply 16 in. Hg to VMV. If vacuum bleeds off immediately, go to next step. If vacuum is not bled off immediately, replace VMV and go to step 61).
  45. Step 50) Check VPWR Circuit Voltage  Turn ignition off. Connect PCM to breakout box. Disconnect VMV wiring harness connector. Turn ignition on. Measure voltage between VPWR terminal of VMV wiring harness connector and battery ground. If voltage is 10.5 volts or more, go to next step. If voltage less than 10.5 volts, repair open in VPWR circuit, repeat QUICK TEST .
  46. Step 51) Check VMV  Turn ignition off. Ensure PCM is connected to breakout box. Reconnect VMV vacuum input hose. Disconnect fuel vapor to carbon canister hose. Connect vacuum gauge to vacuum port. Start engine and allow to idle for 5 minutes. Vacuum gauge should read zero. Connect jumper wire between test pin No. 56 (VMV) and test pin No. 51 or 103 at breakout box. Vacuum should be about engine manifold vacuum. If vacuum is not as specified, replace VMV and go to step 61). If vacuum is as specified, remove vacuum gauge and jumper wire. Go to next step.
  47. Step 52) Check CV Circuit Continuity  Turn ignition off. Disconnect CV solenoid wiring harness connector. Disconnect PCM from breakout box. Measure resistance between test pin No. 67 at breakout box and CV terminal at CV 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 CV circuit. Clear PCM memory and repeat QUICK TEST .
  48. Step 53) Check CV Circuit For Short To Power  Turn ignition on. Measure voltage between test pin No. 67 and test pin No. 51 or 103 at breakout box. If voltage is more than 10.5 volts, repair CV circuit short to VPWR. If voltage is 10.5 volts or less, go to step 61).
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 53) to step 56). No test procedures have been omitted.
  49. Step 56) DTC P1450 Or P1452  Turn ignition off. Remove input vacuum hose from VMV. Connect vacuum pump to VMV. Using vacuum pump, apply 10 in. Hg to solenoid. If vacuum is held for one minute, replace VMV and go to step 61). If vacuum is not held for one minute, remove vacuum pump and go to next step.
  50. Step 57) Check VREF Connectors  Leave ignition off. Check VREF circuit terminal at FTP sensor and PCM. If terminal connectors are okay, go to next step. If terminal connectors are faulty, go to step 61).
  51. Step 58) Check CV Circuit Continuity  Turn ignition off. Disconnect FTP solenoid wiring harness connector. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 90 at breakout box and VREF terminal at FTP sensor wiring harness connector. If resistance is less than 5 ohms, replace FTP sensor and go to next step. If resistance is 5 ohms or more, repair open in VREF circuit and go to next step.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 58) to step 61). No test procedures have been omitted.
  52. Step 61) Verify EVAP System Repair  With ignition on and scan tester connected to DLC, clear PCM memory. Start engine and allow to idle for at least 4 minutes. Drive vehicle 45-60 MPH in high gear for about 8 minutes. Drive vehicle in city traffic condition averaging 25-40 MPH. Ensure at least 5 stop with idle periods of 10 seconds or more. Accelerate vehicle to 45-60 MPH and operate in high gear for about 8 minutes. Stop vehicle and repeat QUICK TEST . If DTC P1000 is present, repeat this step. If any other DTCs are present, service as necessary. See DIAGNOSTIC TROUBLE CODE (DTC) REFERENCE CHART . If no DTCs are present, testing is complete.
scientia non olet · About LEMON Manuals