GM 39 Clutch Switch Circuit Error
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.
New to flash codes? The How to Read GM OBD-I Codes with a Paperclip walks through the test and what the numbers mean. The general OBD-I guide covers the rest.
What does GM code 39 mean?
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
Source
Qualified source review
Sources and review
Review: qualified. Read the source limits below.
- GM and Chevrolet OBD1 Trouble Codes (ALDL Fault Code List)
live reference page (troublecodes.net)
Supports: code identity and GM meaning
Fetched directly. Single publisher, so the record is qualified, not verified. Causes and check order are curator-written from the circuit the code names.
https://www.troublecodes.net/gm/
Last updated 2026-09-19.
Report a correction for 39. Include your vehicle, the issue and a source if you have one.