Intermittent Condition Diagnosis

Most intermittent malfunctions occur under certain conditions. If those conditions can be identified, the cause will be easier to find.

1. Ask the customer about the malfunction: Ask what it feels like, what it sounds like, etc. Then ask about driving conditions, weather, frequency of occurance, and then so on.

2. Determine the conditions from the customers responses: Typically, almost all intermittent malfunctions occur from conditions like vibration, temperature and/or moisture change, poor connections. from the customers replies, it should be reasoned which condition is influenced.

3. In the cases of vibration or poor connections, Attempt to duplicate the customers complaints. Determine the most likely circuit(s) and perform a simulation test on the connectors and parts of that circuit(s). Be sure to use the inspection procedures provided by diagnostic trouble codes and trouble symptoms. For temperature and/or moisture conditions related to intermittent malfunctions, using common sense, try to change the conditions of the suspected circuit components, then use the simulation tests below.

4. Verify the intermittent malfunction is eliminated: Repair the malfunctioning part and try to duplicate the condition(s) again to verify the intermittent malfunction has been eliminated.

Simulation Tests:

SIMULATION TESTS
For these simulation tests, shake then gently bend, pull, and twist the wiring of each of these examples to duplicate the intermittent malfunction.

- Shake the connector up and down, and right and left.
- Shake the wiring harness up and down, and right and left.
- Vibrate the part or sensor.

NOTE: In case of difficulty in finding the cause of the intermittent malfunction, the data recorder function in the scan tool is effective.