636 Transmission fluid temperature higher or lower than expected
How to read it
Code 636 reads as 6 flashes, pause, 3 flashes, pause, 6 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 636 mean?
636. Transmission fluid temperature higher or lower than expected. This code sets when your vehicle computer detects transmission fluid temperature higher or lower than expected.
Common causes of 636
- ATF level
- Wiring
- TFT sensor
- ECM
How to fix 636
- Check the transmission fluid level and condition, and look for slip under load
- Check the circuit wiring and harness for damage, chafing or a poor splice
- Test the TFT 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