Intermittent Problem Inspection Procedure
Sometimes the most difficult case in troubleshooting is when a problem symptom occurs but does not reoccur during test. An example would be if a problem appears only when the vehicle is cold but has not appeared when warm. In this case, the technician should thoroughly make out a "Customer Problem Analysis Sheet" and recreate (simulate) the environment and condition in which the vehicle was having the issue.
- Clear Diagnostic Trouble Code (DTC).
- Inspect all connections, check terminal for poor connections, loose wires, bent, broken or corroded pins, and then verify that the connectors are securely fastened at all times.
- Lightly shake the connector and wiring harness vertically and horizontally.
- Repair or replace the component with a problem.
- Perform road test to verify that the problem has disappeared.
• Simulating Vibration
- Sensors and Actuators
: Lightly shake sensors, actuators or relays by finger.
WARNING: Strong vibration may break sensors, actuators or relays. - Connectors and Harness
: Lightly shake the connector and wiring harness vertically and then horizontally.
• Simulating Heat
- Heat components suspected of causing the malfunction with a hair dryer or other heat source.WARNING:
- DO NOT heat components to the point of damaging them.
- DO NOT heat the ECM directly.
• Simulating Water Sprinkling
- Sprinkle water onto vehicle to simulate a rainy day or a high humidity condition.WARNING: DO NOT sprinkle water directly onto the engine compartment or electronic components.
• Simulating Electrical Load
- Turn on all electrical systems to simulate excessive electrical loads (Radios, fans, lights, rear window defogger, etc.).