Powertrain Controls - ECM/PCM

Code 38 Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION:

NOTE: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to ECM CONNECTOR IDENTIFICATION under ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS for correct color code identification of circuit.

The ECM monitors the status of the brake switch circuits through ECM terminal "P6". Code 38 will set if:

^ No Code 24 is present.

^ Vehicle speed has been above 35 mph for 10 seconds and back to 0 mph 5 times.

^ Status of CKT 420 as monitored with a Scan tool has not changed state from "NO" (released) to "YES" (applied).


DIAGNOSTIC AIDS:

^ A Code 38 in combination with a Code 39 would mean a problem with one or more of the following components. Fuse, CKT 39, brake switch or wire before the splice.


^ A single Code 38 is the result of a wire or CKT 420 problem between the splice and the ECM, poor connection to ECM connector, or possibly the ECM.