Service Precautions

WARNING: This page is about a different car, the 1995 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

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

Always check if any Technical Service Bulletins (TSBs) apply to vehicle.
ALWAYS relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. See FUEL PRESSURE RELEASE .
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.
Vehicle must have a fully charged battery and functional charging system.
Probe PCM 60-pin connector from pin side. DO NOT backprobe PCM 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 instead of a voltmeter.
When checking for spark, ensure coil wire is NO more than 1/4" from ground. If coil wire is more than 1/4" from ground, damage to vehicle electronics and/or PCM may result.
DO NOT prolong testing of fuel injectors, or engine may hydro-statically (liquid) lock.
Always repair lowest trouble code number (MIL) or first trouble code message displayed (scan tool) first.
Always perform verification procedure test after repairs are made.
Always disconnect scan tool after use.
Always disconnect scan tool before charging battery.