634 Manual lever position sensor voltage higher or lower than expected
How to read it
Code 634 reads as 6 flashes, pause, 3 flashes, pause, 4 flashes on the check-engine light. Jumper the self-test input to signal return at the test connector, then run the key on engine off self test and the running self test, counting the check-engine flashes each time.
New to flash codes? The OBD-I code reading guide walks through the paperclip method, code 12, and reading two-digit codes.
What does Ford code 634 mean?
634. Manual lever position sensor voltage higher or lower than expected. This code sets when your vehicle computer detects manual lever position sensor voltage higher or lower than expected.
Common causes of 634
- Incorrect adjustment
- Wiring
- TR sensor
- ECM
How to fix 634
- Check the adjustment and the linkage
- Check the circuit wiring and harness for damage, chafing or a poor splice
- Test the TR sensor and replace it only if it fails its own test
- Test the ECM last, only after every circuit test has passed
- Clear the code, then retest to confirm the fix holds