Intermittent Problem Diagnosis

WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2003 Toyota Tundra, 2003 Toyota Tacoma, 2003 Toyota Sienna, 2003 Toyota Sequoia, and 2003 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a diagnostic trouble code (on some systems) which may help in diagnosis.

If problem vehicle does not produce diagnostic trouble code codes, monitor voltage or resistance values using a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.

Use a DVOM to pinpoint faults. When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.