Intermittent Condition Diagnosis

SYMPTOM DESCRIPTION:
Problems may or may not turn "ON" the CHECK ENGINE light, or store a code.

CAUTION: DO NOT use the FAULT CODE CHARTS in DIAGNOSTIC CHARTS for intermittent problems. The fault must be present to locate the problem. If a fault is intermittent, use of trouble code charts may result in replacement of good parts.



FAULTY ELECTRICAL CONNECTIONS OR WIRING

Most intermittent problems are caused by faulty electrical connections or wiring. Perform careful check of suspect circuits for:

^ Poor mating of the connector halves, or terminals not fully seated in the connector body (backed out).
^ Improperly formed or damaged terminals. All connector terminals in problem circuit should be carefully reformed or replaced to insure proper contact tension.
^ Poor terminal to wire connection. This requires removing the terminal from the connector body to check.



ROAD TEST

If a visual/physical check does not find the cause of the problem, the vehicle can be driven with a voltmeter connected to a suspected circuit, or a SCAN tool can be used. An abnormal voltage or "Scan" reading, when the problem occurs, indicates the problem may be in that circuit.

NOTE: It would be advantageous to make note of any codes stored and clear the ECU/MCU memory prior to road testing. This may eliminate any false codes not related to the complaint.

NOTE: A DRB II or equivalent scan tool is required to perform tests using DIAGNOSTIC CHARTS . There are no component tests, only Diagnostic Test Charts. The Diagnostic Test Charts are located under DIAGNOSTIC CHARTS .