History/Intermittent Failures
WARNING: This page is about a different car, the 1996 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.
History/intermittent codes indicate BCM previously detected a fault which later disappeared. History/intermittent codes can be identified by the letter "H" following the code (i.e., PZ1552H, PZ1556H, 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 indicate problem is within that circuit.