ECM / TCM Incompatible

Possible causes

• CommonModule replaced and never configured to this vehicle
• CommonUsed module fitted from a different vehicle or specification
• CommonProgramming or coding session interrupted
• CommonWrong part number for the market, model year or engine variant
• CommonConfiguration data not transferred during a module swap
• PossibleAftermarket tuning device altering what the module reports

What you might notice

• Transmission stuck in one gear
• Harsh or erratic shifting
• Limp mode
• Fault present since a module was replaced or updated
• Check engine light on

What to check, in order

1. Ask which module was replaced or updated. Updating one and not the other is the usual cause, and it is fixed by bringing them into line rather than by replacing anything.
2. Read both modules' software versions and part numbers.
3. Ask what was done to the vehicle recently. These codes follow work; they do not appear on their own.
4. Read the software and part numbers of the modules involved and compare them against the vehicle's build specification.
5. Do not replace the module. The hardware is almost always right and the configuration is missing.
6. Expect manufacturer-level programming. A generic scan tool can read these codes but cannot resolve them.
7. If a used module was fitted, check whether it can be transferred to this vehicle at all - some are locked to their original VIN.