2001 Pontiac Aztek Base, FWDFACTORY OEM SERVICE PROCEDURE

Diagnostic Procedures

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
  2. Turn off all accessories, including headlights. Turn ignition on, with engine off. Using scan tool, observe ignition 1 signal parameter in PCM data list. If voltage parameter is greater than 13 volts, go to step  7. If voltage parameter is not greater than 13 volts, go to next step.
  3. Using scan tool, command GEN L-terminal on and off. If scan tool indicates that voltage level changes with each command, go to step  7. If voltage level does not change with each command, go to next step.
  4. Turn ignition off. Disconnect generator harness connector. Check voltage between a known-good ground and generator harness connector terminal "B" (Red wire). Using scan tool, command GEN L-terminal on and off. If voltage reading is zero volts with generator off and 5 volts with generator on, go to step  7. If voltage reading is not as specified, go to next step.
  5. Check generator turn on signal circuit (Red wire) for short to ground. Repair as necessary. After repairs, go to step  9. If circuit is okay, go to step  7.
  6. Check for poor connections at generator harness connector. Repair as necessary. After repairs, go to step  9. If connections are okay, go to next step.
  7. Turn ignition off. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to next step. If connections are okay, diagnose charging system.
  8. Replace PCM. Program replacement PCM using required equipment. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  9. Using scan tool, review and record FAIL RECORDS data. Clear DTC. Operate vehicle within the conditions for running this DTC. See CODE ENABLE CRITERIA . Using scan tool, observe SPECIFIC DTC information for this DTC and until test runs. If DTC resets, go to step  2. If DTC does not reset, system is okay.
Chapter Navigation
Return to Chapter: DTC P0620: Generator Performance
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.