Diagnostic System Check - Transmission Codes

On-Board Diagnostic (OBD) System Check:

Powertrain Control Module (PCM):

CIRCUIT SYSTEM DESCRIPTION
The on-board diagnostic system check must be the starting point for any driveability complaint diagnosis. Before using this procedure, you should perform a careful visual/physical check of the Powertrain Control Module (PCM) and engine grounds for being clean and tight.

The on-board diagnostic system check is an organized approach to identifying a problem created by an electronic engine control system malfunction.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for poor connections or a damaged harness. Inspect the PCM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

TEST DESCRIPTION
Number(s) below refer to step number(s) on the diagnostic chart.
1. The Malfunction Indicator Lamp (MIL) should be "ON" steady with the key "ON"/engine "OFF." If not, chart A-1 should be used to isolate the malfunction.
2. Checks the Class II serial data circuit and ensures that the PCM is able to transmit serial data.
3. This test ensures that the PCM is capable of controlling the MIL and the MIL driver circuit is not shorted to ground.
4. If the engine will not start, chart A-3 should be used to diagnose the condition.
6. A scan tool parameter which is not within the typical range may help to isolate the area which is causing the problem.
9. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to PCM Replacement and Programming Procedures in Powertrain Control Module (PCM).