Test Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0621
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Starting and Charging Schematics Connector End View Reference: Engine Electrical Connector End Views |
|||
| 1 | Did you perform the Engine Electrical Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Engine Electrical |
| 2 |
|
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Test the generator turn on signal circuit for a short or open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 6 | Go to Step 4 |
| 4 | Inspect for poor connections at the harness connector of the PCM. Refer to Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 6 | Go to Step 5 |
| 5 | Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement
in Engine Controls - 4.2L. Did you compete the replacement? |
Go to Step 6 | - |
| 6 |
|
Go to Step 2 | System OK |