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Home >> Chevrolet >> 2003 >> Tracker 2D Utility, 4WD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Idle Control System >> Accessory/Electrical Load Idle-Up Signal Diagnosis >> Test Description
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Test Description

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 1  - The Diagnostic System Check - Engine Controls prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
  2. 2  - This step checks whether the PCM is responding to the electrical load idle-up inputs by commanding the IAC valve to increase the IAC Motor Command percentage. The IAC Motor Command parameter on the scan tool should increase 2-3 percent when operating the accessory. If the scan tool does not indicate an increase in the IAC Motor Command when the accessory is turned on, PCM may not be receiving the idle-up signal.
  3. 3  - This step checks whether the PCM is responding to idle-up input signals from the A/C compressor control module. The PCM commands the IAC valve to increase the IAC Motor Command percentage when receiving the idle-up signal. The IAC Motor Command parameter on the scan tool should increase 4-11 percent when operating the A/C. If scan tool does not indicate an increase in the IAC Motor Command when A/C is turned on, PCM may not be receiving the idle-up signal.
  4. 4  - This step checks whether the PCM is responding to the electrical load idle-up input of the PSP switch. The PCM commands the IAC valve to increase the IAC Motor Command percentage when receiving the PSP idle-up signal. The IAC Motor Command parameter on scan tool should increase 2-3 percent when increasing the power steering system pressure. If the scan tool does not indicate an increase in the IAC Motor Command when the accessory is turned on, the PCM may not be receiving the idle-up signal.
  5. 6  - This step checks for voltage from the PCM or for an open or a short to ground in the PSP switch signal circuit.
  6. 7  - This step checks for an inadequate ground connection at the power steering pump or a faulty PSP switch.
  7. 10  - This step checks whether the PCM is receiving the A/C ON signal from the A/C compressor control module.
  8. 11  - The A/C idle-up signal circuit at the PCM should indicate zero volts with A/C ON (operating).
  9. 12  - The A/C idle-up signal circuit at the PCM should indicate battery voltage with A/C OFF (not operating).
  10. 15  - The A/C cut-out signal circuit at the PCM should indicate zero volts with A/C OFF (not operating).
  11. 16  - The A/C cut-out signal circuit at the PCM should indicate battery voltage with A/C ON (operating).
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