PCM Controlled Starter Diagnosis

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

Engine Controls Schematics: Transaxle Range Switch Outputs:

CIRCUIT DESCRIPTION
The PCM controlled starter system consists of the following components:
^ The ignition switch
^ The crank request signal circuit
^ The Powertrain Control Module (PCM)
^ The starter enable (crank) relay
^ The transaxle range switch
^ The starter solenoid

When the ignition switch is turned to the Start position, B+ is sent to the PCM via the Crank Request Signal circuit. The PCM has the ability to disallow starter operation if conditions inappropriate for starter operation exist. The PCM will disable the starter under the following conditions:
^ The engine is running
^ A correct Vehicle Theft Deterrent (VTD) password is not received from the Body Control Module (BCM)
^ The vehicle operator continues to engage the starter for an extended period of time

If no inhibiting conditions are present, and the PCM detects voltage on the Crank Request Signal circuit, the PCM grounds the Starter Enable (Crank) relay control circuit. The Transaxle Range switch must be in Park or Neutral for the control circuit to operate the relay. Current from the crank Maxifuse flows through the relay to the starter solenoid.

DIAGNOSTIC AIDS
This diagnostic procedure is intended to identity electrical malfunctions within the PCM controlled portion of the starting system. For additional system diagnosis, refer to A Diagnostic System Check - Starting and Charging in Diagrams.

Use the J 35616-A connector test adapter kit for any test that requires probing the PCM harness connectors, electrical center fuse/relay cavities, component terminals or a component harness connector. Using this kit will prevent damage caused by improper probing of connector terminals.
If the problem is intermittent, refer to Intermittent Conditions for diagnosis. Intermittent Conditions

Starter Enable (Crank) Relay:

RELAY TERMINAL IDENTIFICATION
Use the following relay cavity table in order to locate the correct cavities to probe during diagnosis. The table layout corresponds to the cavity layout in the underhood accessory junction block. Four blade relays can be inserted 2 ways. Use the table and NOT the numbering on the relay to avoid probing incorrectly.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
2. Ensure that there are no problems with the battery or the battery connections before attempting the starter diagnosis. If the battery required a charge, but was otherwise OK, check for a charging system problem or for a parasitic drain. Refer to A Diagnostic System Check - Starting and Charging or to Battery Electrical Drain/Parasitic Load in Starting and Charging. Testing and Inspection
6. The starter should disengage when the key is released.
7. If the test lamp illuminates, the PCM controlled portion of the circuit is functioning.
10. If the status of the Starter Enable (Crank) relay indicates anything other than OK with the key in either position, there is a problem with the Starter Enable (Crank) relay control circuit.
11. Check for poor connections or terminal tension at the fuse. Refer to Testing for Intermittent and Poor Connections in Diagrams.