Diagnostic Procedure

NOTE: When using diagnostic tests, DO NOT skip any test steps or incorrect diagnosis may result.

Before proceeding with diagnosis, the following precautions must be followed:

Vehicle must have a fully charged battery and functional charging system (belt installed and all wiring connected).
Always check if any Tech Service Bulletins (TSB's) apply to vehicle.
When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in the GENERAL INFORMATION section before disconnecting battery.
Probe PCM 60-pin connector from terminal side. DO NOT backprobe PCM 60-pin connector.
DO NOT cause short circuits when performing electrical tests. This will set additional trouble codes, making diagnosis of original problem more difficult.
DO NOT use a test light in place of a voltmeter.
ALWAYS repair lowest trouble code number first when using MIL method. Repair first trouble code displayed when using scan tool.
ALWAYS perform TEST VER-3A, CHARGING SYSTEM VERIFICATION PROCEDURE after repairs are made.
ALWAYS disconnect scan tool after completing testing, before starting any repairs and before charging battery.