Test Procedures

Intermittent Simulation

To reproduce the conditions which create an intermittent fault, use the following methods:

• Lightly vibrate component.
• Heat component.
• Wiggle or bend wiring harness.
• Spray component with water.
• Remove/apply vacuum source.

Monitor circuit/component voltage or resistance while simulating intermittent. If vehicle is running, monitor for self-diagnostic codes. Use test results to identify a faulty component or circuit.

Component Substitution

If wiring circuits and connectors are okay and a fault code was set for a circuit having a sensor (except Codes 44 and 45), substitute a known good sensor and recheck system. A faulty relay, switch or solenoid which is driven by the ECM may cause an electrical surge when operated. Check SES light or Scan tester for an intermittent when the component is operated.