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Home >> Ford >> 1986 >> Taurus MT5, 4D Sedan >> Repair and Diagnosis >> Engine Performance >> System >> 2.5L CFI EEC IV Testing >> Circuit Tests >> Test UU - IRCM (Integral Relay Control Module)

Test UU - IRCM (Integral Relay Control Module)

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: fuel lines and fuel filters, contaminated fuel, fuel pump, ignition switch, battery cables and ground straps, alternator and voltage regulator, A/C clutch or A/C demand, and cooling fan motor.

  1. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage across battery terminals. If reading is less than 10.5 volts, service or replace discharged battery. If reading is 10.5 volts or more, go to next step.
  2. Turn key on, leaving engine off. Disconnect ECA and set DVOM on 20-volt scale. Measure voltage between negative battery post and signal return circuit in SELF-TEST connector. If reading is less than 0.5-volts, go to step 6). If reading is 0.5 volts or more, go to next step.
  3. Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, and connect ECA to box. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between negative battery post and test pins 40 and 60. If one or both readings are 0.5-volts or higher, repair open in circuit(s) and repeat QUICK TEST  . If both readings are less than 0.5-volts, go to next step.
  4. Turn key off and wait 10 seconds. With breakout box installed and ECA connected, set DVOM on 200-ohm scale. Measure resistance between test pin 46 and 40, and between test pin 46 and 60. If one or both readings are 5 ohms or higher, disconnect ECA connector. Inspect connector for damage, repair if necessary and repeat this step. If fault is still present, replace ECA and repeat QUICK TEST  . If both readings are less than 5 ohms, go to next step.
  5. Turn key off and wait 10 seconds. With breakout box and ECA connected, set DVOM on 200-ohm scale. Measure resistance between test pin 46 and signal return circuit at SELF-TEST connector. If reading is less than 5 ohms, system is okay. Repeat QUICK TEST  . If reading is 5 ohms or higher, correct cause of high resistance in signal return circuit. Repeat QUICK TEST  .
  6. Turn key off and disconnect Integral Relay Control Module (IRCM). Set DVOM on 20-volt scale. Measure voltage between IRCM harness connector pin 10A (battery) and pin 4B (ground). If reading is less than 10.5-volts, go to step 9). If reading is 10.5-volts or higher, go to next step.
  7. With IRCM disconnected and DVOM on 20-volt scale, turn key on. Measure voltage between pin 8B and 4B at IRCM harness connector. If reading is less than 10.5-volts, repair open between pin 8B and ignition switch. Connect IRCM and repeat QUICK TEST  . If reading is 10.5-volts or more, go to next step.
  8. Turn key off. 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 from test pin 37 and 57 to IRCM harness connector pin 6A. If reading is 5 ohms or higher, repair open in VPWR circuit. Connect IRCM and repeat QUICK TEST  . If reading is less than 5 ohms, replace IRCM and repeat QUICK TEST  .
  9. With key off and IRCM disconnected, set DVOM on 200-ohm scale. Measure resistance from negative battery post to IRCM harness connector pin 4B. If reading is 5 ohms or higher, repair open in ground circuit to IRCM harness connector pin 4B. Repeat QUICK TEST  . If reading is less than 5 ohms, repair open in power circuit to IRCM harness connector pin 10A. Repeat QUICK TEST  .
  10. Turn key on, leaving engine off. Locate fuel pump(s). Set DVOM on 20-volt scale. Measure voltage between chassis ground and power-to-pump(s) circuit at fuel pump while cranking engine. If reading is 8.0-volts or higher, service electric fuel pump system. If reading is less than 8.0-volts, go to next step.
  11. Turn key off and wait 10 seconds. Locate and disconnect fuel pump inertia switch. Set DVOM on 200-ohm scale. Measure resistance across fuel pump inertia switch. If reading is 5 ohms or higher, replace fuel pump inertia switch and repeat QUICK TEST  . If reading is less than 5 ohms, go to next step.
  12. With key off and DVOM on 200-ohm scale, disconnect IRCM and fuel pump(s). Measure resistance between IRCM harness connector pin 8A and harness connector at fuel pump(s). If reading is less than 5 ohms, replace IRCM. Connect all components and repeat QUICK TEST  . If reading is 5 ohms or higher, repair open in power-to-pump(s) circuit. Connect IRCM and repeat QUICK TEST  .
  13. With key off and DVOM on 200-ohm scale, disconnect IRCM and fuel pump(s). Measure resistance from IRCM harness connector pin 8A to pin 6A (VPWR) and battery positive post. If any reading is less than 10,000 ohms, repair short circuit. Connect all components and attempt to start vehicle. If vehicle runs, repeat QUICK TEST  . If vehicle does not run, replace IRCM and repeat QUICK TEST  . If all readings are 10,000 ohms or higher, replace IRCM and repeat QUICK TEST  .
  14. Code 87 Displayed. Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM and set DVOM on 200-ohm scale. Measure resistance of fuel pump(s) circuit, from test pin 22 to IRCM harness connector pin 5A. If reading is 5 ohms or higher, repair open in fuel pump circuit. Connect all components and repeat QUICK TEST  . If reading is less than 5 ohms, go to next step.
  15. With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200,000-ohm scale. Measure resistance between test pin 22 and test pins 37, 57, and battery positive post. Measure resistance between test pins 22, 40, 60, and battery negative terminal. If any reading is less than 10,000 ohms, repair fuel pump(s) circuit shorts to power or ground. Connect all components and repeat QUICK TEST  . If code 87 is still present, go to next step. If all readings are 10,000 ohms or higher, go to next step.
  16. Turn key off. Disconnect IRCM and set DVOM on 200-ohm scale. Measure resistance of IRCM between pin 5A and 6A. If resistance is between 65 and 100 ohms, replace ECA. Connect all components and repeat QUICK TEST  . If resistance is not between 65 and 100 ohms, replace IRCM. Connect all components and repeat QUICK TEST  .
  17. No Fan, No Code 83. Turn key off. Disconnect IRCM and set DVOM on 20-volt scale. Measure voltage between battery negative post and IRCM harness connector pins 1A, 4A, and 7A. If any reading is less than 10.5-volts, service open in power circuit. Re-evaluate symptom. If all readings are 10.5-volts or higher, go to next step.
  18. Turn key off and disconnect IRCM 10-pin connector. Install a jumper wire between IRCM harness connector pin 1A and 2A. If cooling fan does not run, go to step 20). If cooling fan runs, go to next step.
  19. Turn key off. Connect IRCM and disconnect ECA. Turn key on. If fan does not run at low speed, go to step 21). If fan runs at low speed, go to step 23).
  20. With key off and IRCM 10-pin connector disconnected, disconnect cooling fan harness. Install a jumper wire between IRCM harness connector pins 1A and 2A. Set DVOM on 20-volt scale and measure voltage at cooling fan harness connector. If reading is 8.0 volts or higher, replace cooling fan and re-evaluate symptom. If reading is less than 8.0-volts, go to step 22).
  21. Turn key off. Disconnect ECA and IRCM. Set DVOM on 200,000-ohm scale. Measure resistance between IRCM harness connector pin 1B and 4B. If reading is 10,000 ohms or more, replace IRCM. Connect all components and re-evaluate symptom. If reading is less than 10,000 ohms, repair short to ground in EDF circuit. Connect all components and re-evaluate symptom.
  22. Turn key off. Disconnect cooling fan and IRCM 10-pin connector. Install a jumper wire between IRCM harness connector pin 1A and 2A. Set DVOM on 20-volt scale and measure voltage at cooling fan harness connector. If reading is 8.0-volts or higher, repair open in cooling fan ground circuit. Connect IRCM and re-evaluate symptom. If reading is less than 8.0-volts, repair open in power-to-fan circuit from IRCM harness connector pins 2A and 9A to cooling fan connector. Connect IRCM and re-evaluate symptom.
  23. Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. With IRCM connected, install a jumper wire between test pin 52 and 40. If fan does not run at high speed, replace IRCM. Connect ECA and re-evaluate symptom. If fan runs at high speed, go to next step.
  24. Connect ECA and check engine coolant level. Warm engine to normal operating temperature. Turn key off and wait 10 seconds. Disconnect Engine Coolant Temperature (ECT) sensor harness. Set DVOM on 200,000-ohm scale. Measure resistance of ECT sensor. If reading is between 1500 and 2000 ohms, replace ECA. Connect all components and re-evaluate symptom. If reading is not between 1500 and 2000 ohms, replace ECT sensor. Connect all components and re-evaluate symptom.
  25. Code 83 Displayed. Turn key off and disconnect IRCM. Set DVOM on 200-ohm scale. Measure resistance of IRCM between pin 3A and 6A. If reading is not between 50 and 100 ohms, replace ECA and repeat QUICK TEST  . If reading is between 50 and 100 ohms, go to next step.
  26. Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM 10-pin connector. Set DVOM on 200-ohm scale and measure continuity between test pin 52 and IRCM harness connector pin 3A. If reading is more than 5 ohms, repair open in HEDF circuit. Connect all components and repeat QUICK TEST  . If reading is 5 ohms or less, go to next step.
  27. With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200,000-ohm scale. Measure resistance between test pin 52 and 40. If reading is 10,000 ohms or less, repair short to ground in HEDF circuit. Repeat QUICK TEST  . If reading is more than 10,000 ohms, go to next step.
  28. With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200,000-ohm scale. Measure resistance between test pin 52 and 37. If reading is more than 10,000 ohms, replace ECA. Connect all components and repeat QUICK TEST  . If reading is 10,000 ohms or less, repair short to power. Connect all components and repeat QUICK TEST  . If code 83 is still present, replace ECA and repeat QUICK TEST  .
  29. Fan Always On, No Code 83 or 67. Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM and set DVOM on 200-ohm scale. Measure resistance between test pin 55 and IRCM harness connector pin 1B. If reading is more than 5 ohms, repair open in EDF circuit. Connect all components and re-evaluate symptom. If reading is 5 ohms or less, go to next step.
  30. With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200,000-ohm scale. Measure resistance between test pin 55 and 37, and from test pin 55 to battery positive post. If reading is 10,000 ohms or less, repair short to power in EDF circuit, then go to next step. If reading is more than 10,000 ohms, go to next step.
  31. With key off, breakout box installed and ECA disconnected, connect IRCM. Install a jumper wire between test pin 55 and 40 or 60. If cooling fan continues to run, replace IRCM. Re-evaluate symptom. If cooling fans stops running, replace ECA. Re-evaluate symptom.
  32. No Fan. Turn key off. Disconnect IRCM and set DVOM on 20 volt scale. Measure voltage between battery negative post and pin 7A at IRCM harness connector. If reading is less than 10.5-volts, repair open in power circuit. Re-evaluate symptom. If reading is 10.5 volts or higher, go to next step.
  33. Turn key off and disconnect IRCM 10-pin connector. Install a jumper wire between IRCM harness connector pin 2A and 7A. If cooling fan does not run, go to step 35). If cooling fan runs, go to next step.
  34. With key off and ECA disconnected, connect IRCM. Turn key on. If cooling fan does not run, go to step 36). If cooling fan runs, go to step 38).
  35. Turn key off. Disconnect cooling fan harness and IRCM 10 pin connector. Install a jumper wire between IRCM harness connector pin 2A and 7A. Set DVOM on 20-volt scale and measure voltage at cooling fan harness connector. If reading is 8.0-volts or higher, replace cooling fan and re-evaluate symptom. If reading is less than 8.0-volts, go to step 37).
  36. Turn key off. Disconnect ECA and IRCM. Set DVOM on 200,000-ohm scale and measure resistance between IRCM harness connector 1B and 4B. If reading is 10,000 ohms or higher, replace IRCM. Connect all components and re-evaluate symptom. If reading is less than 10,000 ohms, repair short to ground in EDF circuit. Connect all components and re-evaluate symptom.
  37. Turn key off and disconnect cooling fan. Disconnect IRCM 10-pin connector. Install a jumper wire between IRCM harness connector pin 2A and 7A. Set DVOM on 20-volt scale and measure voltage at cooling fan harness connector. If reading is 8.0-volts or higher, repair open in fan ground circuit. Connect IRCM and re-evaluate symptom. If reading is less than 8.0-volts, repair open in power-to fan circuit from IRCM harness connector pin 2A and 9A to cooling fan connector. Connect IRCM and re-evaluate symptom.
  38. Connect ECA and check engine coolant level. Warm engine to normal operating temperature. Turn key off and wait 10 seconds. Disconnect ECT sensor. Set DVOM on 200,000-ohm scale and measure resistance of ECT sensor. If reading is between 1500 and 2000 ohms, replace ECA. Connect all components and re-evaluate symptom. If reading is not between 1500 and 2000 ohms, replace ECT sensor. Connect all components and re-evaluate symptom.
  39. Turn key on, leaving engine off. Place A/C demand switch to A/C on position. Set DVOM on 20-volt scale and check voltage at A/C clutch harness connector. If reading is 10.5-volts or higher, service A/C compressor and/or system. If reading is less than 10.5 volts, go to next step.
  40. Turn key off and disconnect IRCM 8-pin connector. Set DVOM on 200-ohm scale and measure resistance between IRCM harness connector pin 5B and power circuit at A/C clutch harness connector. If reading is more than 5 ohms, repair open in power to A/C circuit then re-evaluate symptom. If reading is 5 ohms or less, go to next step.
    NOTE: DO NOT  use STAR tester in step 41), use DVOM only. Enter OUTPUT STATE CHECK as specified in test. For additional information see QUICK TEST DIAGNOSTIC AIDS  , OUTPUT STATE CHECK in front of this article.
  41. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Connect DVOM negative test lead to Self-Test Output (STO) and positive lead to battery positive terminal. Using a jumper wire connect Self-Test Input (STI) to signal return at SELF-TEST connector. Perform KEY ON/ENGINE OFF SELF-TEST until completion of CONTINUOUS SELF-TEST codes (DVOM reads zero volts). Depress and release throttle. DVOM should change to a high voltage reading. If DVOM did not change, depress throttle to wide open throttle (WOT) and release. If STO voltage does not go to high, go to TEST NN - NO CODES/CODES NOT LISTED, step 17). If DVOM changes, remain in OUTPUT STATE CHECK and go to next step.
  42. Turn key on, leaving engine off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, and connect ECA. Place A/C demand switch to A/C on position. Set DVOM on 20-volt scale. Connect DVOM positive test lead to pin 37 and negative test lead to pin 54. While observing DVOM, depress and release throttle several times (to cycle output on and off). If output does not cycle, go to step 46). If output cycles, go to next step.
  43. With key on, engine off and A/C demand switch in A/C on position, verify that breakout box is installed and that ECA and IRCM are connected. Set DVOM on 20-volt scale and measure voltage between test pin 10 and 40. If reading is less than 10.5-volts, go to step 45). If reading is 10.5-volts or higher, go to next step.
  44. Turn key off and wait 10 seconds. Disconnect ECA and IRCM 8-pin connector. Set DVOM on 200-ohm scale and measure resistance between test pin 10 and IRCM harness connector pin 2B. If reading is more than 5 ohms, service open in ACCS circuit and re-evaluate symptom. If reading is 5 ohms or less, replace IRCM and re-evaluate symptom.
  45. Turn key off and wait 10 seconds. Place A/C demand switch to A/C on position. Set DVOM on 200-ohm scale and measure resistance between test pin 10 and A/C demand switch. If reading is 5 ohms or less, EEC-IV system is okay. Service A/C system. If reading is more than 5 ohms, repair open in switch circuit. Repeat QUICK TEST  .
  46. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM 8-pin connector. Set DVOM on 200-ohm scale and measure resistance between test pin 54 and IRCM harness connector pin 7B. If reading is more than 50 ohms, repair open in WAC circuit then re-evaluate symptom. If reading is 50 ohms or less, go to next step.
  47. Turn key off and wait 10 seconds. Leave breakout box installed, and ECA disconnected. Disconnect IRCM 8-pin connector. Set DVOM on 200-ohm scale. Measure resistance between test pin 54 and 40, between test pin 54 and 46, and between test pin 54 and battery negative post. If any reading is less than 10,000 ohms, repair shorts to ground in WAC circuit then re-evaluate symptom. If all readings are 10,000 ohms or higher, go to next step.
  48. Turn key off and wait 10 seconds. Leave breakout box installed, and ECA disconnected. Disconnect IRCM 8-pin connector. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 54 and 37, and between test pin 54 and battery positive post. If any reading is less than 10,000 ohms, repair shorts to power in WAC circuit and then go to next step. If all readings are 10,000 ohms or higher, go to next step.
  49. Turn key off and wait 10 seconds. Leave breakout box installed, and ECA disconnected. Connect IRCM 8-pin connector and disconnect A/C clutch harness. Place A/C demand switch to A/C on position. Turn key on, leaving engine off. Set DVOM on 20-volt scale and measure voltage at A/C clutch harness connector. If reading is more than 10.5-volts, replace ECA then re-evaluate symptom. If reading is less than 10.5-volts, replace IRCM then re-evaluate symptom.
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