Powertrain Controls - ECM/PCM

Code 38 Diagnostic Chart:

TCC Solenoid And Brake Switch Input Circuit Diagram:

CIRCUIT DESCRIPTION:
The PCM monitors the status of the TCC brake switch input circuits through PCM terminal "BA5". 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 five times.
^ Status of CKT 420 has not changed state at least once (released/applied).

DIAGNOSTIC AIDS:
^ A Code 38 in combination with a Code 26 would mean a problem with one or more of the following components. Fuse, CKT 250, brake switch, or wire between brake switch and the splice (circuit 420).

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

NOTES:

^ If the brake switch has failed in an open state, TCC will not engage.
^ When code 38 is set, the PCM will not allow 4th gear or TCC operation.
^ Code 38 does not turn "ON" the SERVICE ENGINE SOON light.