P0614: ECM/TCM Incompatible
P0614 means the engine computer and the transmission computer do not match, either because their software variants differ or because one module was never registered with the other. The car is often drivable, but the check engine light stays on, and in some cases the transmission may limit its shifting, so have it checked soon.
You can drive, but get it checked soon
Some cars show no other symptoms, but the transmission can go into limp mode (a protective mode with limited shifting), so drive only as needed until a shop checks it.
What it means
The engine control module (ECM) and the transmission control module (TCM) have to work as a pair. The ECM checks that its software or calibration variant fits the transmission module and transmission type that are installed, or that the transmission module is registered. If the variant is wrong or the registration is missing, it stores P0614 and turns on the check engine light. Some engines run this check continuously with the ignition on and light the lamp on the first trip, and an incomplete programming job can trigger it too. The usual situations are a replacement or used module from a car with a different gearbox, or a software update that was applied to only one of the two modules. On some systems the code sets with no other reaction from the car.
Likely causes
- Engine or transmission module replaced and not matched or registeredVery likely
A new module normally has to be programmed and registered to the car, and without that step the two modules do not recognize each other.
- Used module with the wrong variant (different gearbox or engine)Possible
A module taken from a car with a different gearbox or engine carries a variant that does not fit this car.
- Software update on only one of the two modulesPossible
If only one module gets the update, the two software versions no longer agree.
- Internal engine module faultLess likely
A fault inside the engine module can make it misjudge the match, though this is the least common reason.
What you may notice
- Check engine light on
- Possibly transmission limp mode or limited shifting
- Sometimes no other symptoms
What to check, cheapest first
- 1Think back: was the engine module or transmission module replaced, reprogrammed, or updated before the light came on? · you can do it
- 2Check whether the replacement module came from a car with a different gearbox or engine. · you can do it
- 3Read all stored codes with a scan tool and note related ones such as P0613, P0631, P0630, P0610, and P0602. · mechanic
- 4Compare the software and calibration versions of both modules with what the car requires. · mechanic
- 5Reprogram or register the modules so they match, or install the correct variant if the module is wrong. · mechanic
- 6Clear the code and confirm it does not return; if it does, test the engine module for an internal fault. · mechanic
Related codes
Frequently asked questions
Can I drive with P0614?+
Often yes for a short time, but the transmission may enter limp mode with limited shifting. Get it checked soon.
Can a loose gas cap cause P0614?+
No. This code is about the engine and transmission modules not matching, not the fuel system.
Will P0614 pass an emissions test?+
Probably not. The code is emissions relevant and keeps the check engine light on, so it needs to be fixed first.
Can I fix P0614 myself?+
Usually not. Matching or programming modules needs special equipment, and the repair is estimated at 0.5 to 1.5 hours at a shop.
Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10