History/Intermittent Failures

History/intermittent codes indicate CCM previously detected a fault which later disappeared. History/intermittent codes can be identified by the number "1" preceding the code (i.e., 120, 132, 137, etc.). If a history/intermittent code is set, fault may be intermittent or the system for which the code is set may not be currently operating.

Intermittent failures may be caused by problems with electrical circuit. If a visual inspection does not locate problem, vehicle may be driven with a DVOM attached to suspect circuit. Abnormal voltage or resistance readings when problem occurs may indicates problem is within that circuit.

Some circuits may be monitored while operating vehicle and observing Heater and Air Conditioning (H-A/C) control panel. If code changes status from current t to history/intermittent while observing display when problem occurs, problem may possibly be within that circuit for which code is displayed. History/intermittent codes will clear from CCM memory if fault does not repeat for 50 ignition cycles.