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Home >> Chevrolet >> 2003 >> Tracker 2D Utility, RWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Idle Control System >> Accessory/Electrical Load Idle-Up Signal Diagnosis >> Diagnostic Procedures
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Diagnostic Procedures

NOTE: For wiring diagrams, see WIRING DIAGRAMS .
  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK- ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 2.0L TRACKER article or DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 2.5L TRACKER article. After performing Diagnostic System Check - Engine Controls, go to next step.
    2. NOTE: If headlights, HVAC blower motor or rear defogger do not operate properly, diagnose these components first.
  2. Install scan tool. Start engine. Operate engine until normal operating temperature is reached. Turn off all accessories. Monitor Engine Speed and IAC Motor Command parameters on scan tool while turning each of the following electrical accessories ON and OFF. Headlights, HVAC, blower motor, and rear window defogger. Did scan tool indicate an increase in the IAC Motor Command when each accessory was turned on? If yes, go to next step. If no, go to step  20.
  3. Turn OFF all accessories. Turn A/C switch ON and blower speed selector switch to any position, except OFF. Monitor Engine Speed and IAC Motor Command parameters on scan tool, while operating the A/C system. Did scan tool indicate an increase in IAC Motor Command when A/C compressor was engaged? If yes, go to next step. If no, go to step  10.
  4. Turn OFF all accessories. Monitor Engine Speed and IAC Motor Command parameters on scan tool while turning steering wheel all the way to the right and all the way to the left. Did scan tool indicate an increase in IAC Motor Command when turning the steering wheel from the right to the left? If yes, refer to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.0L & 2.5L TRACKER article. If no, go to next step.
  5. Turn OFF all accessories. Monitor Power Steering Switch on scan tool. Turn steering wheel all the way to the right and all the way to the left. Did scan tool indicate High Pressure when steering wheel was turned all the way in either direction? If yes, go to IDLE AIR CONTROL SYSTEM DIAGNOSIS . If no, go to next step.
  6. Turn ignition on, with engine off. Disconnect PSP switch electrical connector. Using a DVOM, measure voltage from the PSP switch harness connector to ground. Was voltage reading about battery voltage? If yes, go to next step. If no, go to step  8.
  7. Connect a test light to battery voltage. Probe PSP switch connector, switch side, with test light. Start engine. Observe test light while turning steering wheel all the way to the right and all the way to the left. Was test light on when steering wheel was turned all the way to the right or left? If yes, go to DIAGNOSTIC AIDS . If no, go to step  9.
  8. Check for open or short to ground in the PSP signal circuit between the PCM and PSP switch. Repair as necessary. Was a repair necessary? If yes, go to step  30. If no, go to step  29.
  9. Check for a faulty ground connection at power steering pump. Repair as necessary. Was a repair necessary? If yes, go to step  30. If no, go to step  28.
  10. Monitor A/C Relay Command parameter on scan tool. Turn A/C switch ON and blower speed selector switch to any position, except OFF. Does scan tool indicate ON when A/C compressor is operating? If yes, go to IDLE AIR CONTROL SYSTEM DIAGNOSIS . If no, go to next step.
  11. Start engine. Turn A/C on (A/C operating). Using DVOM connected to ground, backprobe the A/C idle-up signal circuit at the PCM connector. Measure voltage ON when the A/C compressor is operating. Is voltage reading zero volts? If yes, go to next step. If no, go to step  14.
  12. Start engine. Turn A/C off. Using DVOM connected to ground, backprobe the A/C idle-up signal circuit at the PCM connector. Measure voltage. Is voltage reading is at battery voltage? If yes, go to step  15. If no, go to next step.
  13. Turn ignition off. Disconnect PCM harness connector C1. Back out the A/C idle-up signal wire from the PCM harness connector. Reconnect PCM harness connector C1. Turn ignition on, with engine off. Backprobe through the PCM harness connector slot to the PCM terminal with a DVOM connected to ground. Is voltage reading at battery voltage? If yes, go to next step. If no, go to step  29.
  14. Check for an open or a short in the A/C idle up signal circuit between the PCM and A/C compressor control module. Repair as necessary. Was a repair necessary? If yes, go to step  30. If no, go to step  19.
  15. Start engine. Turn A/C off. Backprobe the A/C cut-out signal circuit at the PCM connector with DVOM connected to ground. Measure voltage. Is voltage reading at zero volts? If yes, go to next step. If yes, go to step  29.
  16. Start engine. Turn A/C on (A/C operating). Backprobe the A/C cut-out signal circuit at the PCM connector with DVOM connected to ground. Measure voltage. Is voltage at battery voltage? If yes, DIAGNOSTIC AIDS . If no, go to next step.
  17. Check for an open or short to ground in the A/C cut-out signal circuit between the PCM and A/C compressor control module. Repair as necessary. Was repair necessary? If yes, go to step  30. If no, go to next step.
  18. Disconnect A/C compressor control module electrical connector. Turn ignition on, with engine off. Measure voltage of the A/C cut-out signal circuit at terminal No. 5 of the A/C compressor control module with a DVOM. Is voltage reading at battery voltage? If yes, go to step  29. If no, go to next step.
  19. The A/C compressor control module is malfunctioning. Inspect A/C compressor control module and circuitry for a fault. Repair as necessary. After repairs, go to step  30.
  20. Did the scan tool indicate an increase in IAC Motor Command when HVAC blower motor was turned on? If yes, go to step  22. If no, go to next step.
  21. Turn ignition off. Disconnect PCM electrical connectors. Turn ignition on, with engine off. Probe the harness side of the HVAC Blower Idle-Up Signal circuit with a test light connected to battery voltage. Observe test light while operating the HVAC blower motor switch. Did the test light illuminate when HVAC blower motor switch was turned on? If yes, go to step  29. If no, go to step  25.
  22. Did scan tool indicate an increase in the IAC Motor Command when rear window defogger switch was turned on? If yes, go to next step. If no, go to step  24.
  23. Probe the electrical load idle-up circuit of the exterior lighting system at the PCM connector, with test light connected to ground. Observe test light while operating the headlight switch. Did the test light illuminate when headlight switch was turned on? If yes, go to step  29. If no, go to step  26.
  24. Probe the electrical load idle-up circuit of the rear defogger switch at the PCM connector, with a test light connected to ground. Observe test light while operating the rear defogger switch. Did the test light illuminate when rear defogger switch was turned on? If yes, go to step  29. If no, go to step  27.
  25. Inspect for correct operation of the HVAC blower circuit. Inspect the HVAC blower circuit for an open or a short. Repair any faults found, as necessary. Did you find and correct the condition? If yes, go to step  30. If no, go to step  29.
  26. Inspect for correct operation exterior lighting circuit. Inspect the exterior lighting circuit for an open or a short. Repair any faults found, as necessary. Did you find and correct the condition? If yes, go to step  30. If no, go to step  29.
  27. Inspect for correct operation rear defogger circuit. Inspect the rear defogger circuit for an open or a short. Repair any faults found, as necessary. Did you find and correct the condition? If yes, go to step  30. If no, go to step  29.
  28. Replace PSP switch. After replacing switch, go to step  30.
  29. Replace PCM. See REMOVAL & INSTALLATION - TRACKER article. After repairs, go to next step.
  30. Operate vehicle within the conditions in which the customer concern was first noticed. Is the concern still present? If yes, diagnose affected DTC(s). Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.0L TRACKER article or DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 2.5L TRACKER article. If no DTC(s) are set, system is okay.
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