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).
DO NOT backprobe PCM connector. Probe PCM connector from pin side.
DO NOT cause short circuits when performing electrical tests. This will set additional fault codes, making diagnosis of original problem more difficult.
DO NOT use a test light in place of a voltmeter.
ALWAYS repair lowest fault code number first when using CHECK ENGINE light method. Repair first fault code displayed when using DRB-II.
ALWAYS perform verification procedure test after repairs are made.
ALWAYS disconnect DRB-II after completing testing, before starting any repairs and before charging battery.