What causes GM code 39?

Failed clutch or TCC release switch Misadjusted switch at the pedal Open or shorted wiring to the ECM On automatics a TCC stuck off condition uses this same code

How do I fix GM code 39?

Check switch operation and adjustment at the pedal Test switch continuity pressed and released Inspect wiring for opens and chafing along the pedal bracket On automatics test TCC apply per the service manual Clear codes and verify the input changes state on a scan tool

39 Clutch Switch Circuit Error

Q: What does GM code 39 mean?

GM code 39. Clutch Switch Circuit Error. Applies to 1988-1995 GM cars and trucks with manual or automatic transmission and TCC.

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

How to read it

Code 39 reads as 3 flashes, pause, 9 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 39 mean?

39. Clutch Switch Circuit Error. This code sets when your vehicle computer detects clutch switch circuit error.

Common causes of 39

Failed clutch or TCC release switch
Misadjusted switch at the pedal
Open or shorted wiring to the ECM
On automatics a TCC stuck off condition uses this same code

How to fix 39

Check switch operation and adjustment at the pedal
Test switch continuity pressed and released
Inspect wiring for opens and chafing along the pedal bracket
On automatics test TCC apply per the service manual
Clear codes and verify the input changes state on a scan tool