Service Precautions

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

• Vehicle must have a fully charged battery and functional charging system.
• When testing voltage or continuity at any control module, use terminal side and not wire end. DO NOT probe a wire through insulation.
• Always start at RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES  under SYSTEM TESTS. Starting with any other test may result in incorrect results.
• Only perform test steps indicated. It is not necessary to perform all steps in a test.
• Turn ignition switch to OFF position before disconnecting or connecting components.
• Use extreme care when connecting or disconnecting wiring during testing to prevent accidental grounding or shorting.
• Unless instructed to do so in test steps, DO NOT use a test light in place of a voltmeter.
• Always disconnect scan tool after use.
• Always disconnect scan tool before charging battery.
• Always perform appropriate VERIFICATION TESTS  after repairs are made.