What causes GM code 38?

Brake switch stuck in one position Shorted wiring between the brake switch and ECM Failed TCC solenoid confusing diagnosis on some models Corroded ECM connector pin for the brake input

How do I fix GM code 38?

Test brake switch continuity in both pedal positions Check that TCC applies in overdrive and releases with light braking Inspect wiring for shorts to ground or power Test the TCC solenoid circuit if the brake input tests good Clear codes and confirm normal lockup behavior on a road test

38 TCC Brake Switch Circuit Error

Q: What does GM code 38 mean?

GM code 38. TCC Brake Switch Circuit Error. Applies to 1988-1995 GM cars and trucks with automatic transmission and TCC.

Make: GM (1982-1995)
Category: Powertrain - Transmission
Severity: Check Engine Light
Applies to: 1988-1995 GM cars and trucks with automatic transmission and TCC

How to read it

Code 38 reads as 3 flashes, pause, 8 flashes on the check-engine light. Jump terminals A and B on the ALDL connector with the key off, then turn the key on with the engine off and count the check-engine flashes.

What does GM code 38 mean?

38. TCC Brake Switch Circuit Error. This code sets when your vehicle computer detects tcc brake switch circuit error.

Common causes of 38

Brake switch stuck in one position
Shorted wiring between the brake switch and ECM
Failed TCC solenoid confusing diagnosis on some models
Corroded ECM connector pin for the brake input

How to fix 38

Test brake switch continuity in both pedal positions
Check that TCC applies in overdrive and releases with light braking
Inspect wiring for shorts to ground or power
Test the TCC solenoid circuit if the brake input tests good
Clear codes and confirm normal lockup behavior on a road test