Crank Request Signal Circuit Diagnosis

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Engine Controls Schematics: PCM Power and Grounds:

CIRCUIT DESCRIPTION
The PCM controlled starter system consists of the following components:
^ The ignition switch
^ The Crank Request Signal circuit
^ The 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 Powertrain Control Module (PCM) via the Crank Request Signal circuit. The PCM has the ability to disallow starter operation it 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 identify electrical malfunctions within the PCM controlled portion of the starting system.

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

TEST DESCRIPTION
The number below refers to the step number on the diagnostic table.
2. Verifies whether the fault is currently present.