Basic Inspection Procedure
Measuring Condition of Electronic Parts' Resistance
The measured resistance at high temperature after vehicle running may be high or low. So all resistance must be measured at ambient temperature (20°C, 68°F), unless stated otherwise.
Intermittent Problem Inspection Procedure
Sometimes the most difficult case in troubleshooting is when a problem symptom occurs but does not occur again during testing. 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 which occurred when the vehicle was having the issue.
- Clear Diagnostic Trouble Code (DTC).
- Inspect connector connection, and check terminal for poor connections, loose wires, bent, broken or corroded pins, and then verify that the connectors are always securely fastened.
- Slightly shake the connector and wiring harness vertically and horizontally.
- Repair or replace the component that has a problem.
- Verify that the problem has disappeared with the road test.
- Simulating Vibration
- Sensors and Actuators
: Slightly vibrate sensors, actuators or relays with 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 where they may be damaged.
- 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 into 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.).