Intermittent Code

A diagnostic trouble code that is not present every time the PCM checks the circuit is an "intermittent" code. Most intermittent codes are caused by wiring or connector problems. Intermittent conditions that come and go like this are the most difficult to diagnose; they must be looked for under specific conditions that cause them. The following procedures may assist you in identifying a possible intermittent problem:

• Visually inspect related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals.
• Visually inspect the related harnesses. Look for chafed, pierced, or partially broken wire.
• Refer to any S.T.A.R. Hotline Newsletters, Service Information Tune ups (SITs) or Service Bulletins that may apply.
• Use the DRBIII® data recorder or co-pilot.

Some Transmission intermittent DTCs are caused by wiring or connector problems. However intermittent Speed ratio codes are usually caused by intermittent hydraulic seal leakage in the clutch and/or accumulator circuits. Intermittent speed ratio codes can be set by intermittent speed sensor circuitry or by line noise being induced onto one or both of the speed sensor signal circuits. Problems that come and go like this are the most difficult to diagnose, they must be looked for under the specific conditions that cause them.