The P0633 trouble code indicates that an immobilizer key is not programmed into the Engine Control Module (ECM) or Powertrain Control Module (PCM).
P0633 Immobilizer Key Not Programmed – ECM/PCM
Code symptoms P0633.
1. Check Engine Light (CEL) illuminated on the dashboard.
2. Vehicle may not start.
3. Poor engine performance.
4. Transmission may not shift properly.
5. Immobilizer warning light illuminated on the dashboard.
This code is common in brands such as:: Chevrolet, Renault, Ford, Toyota, Nissan, Mercedes Benz, Honda.
Causes of the code P0633.
1. Faulty ECM or PCM.
2. ECM or PCM programming error.
3. Immobilizer key not properly programmed or recognized by the ECM or PCM.
4. Faulty wiring or connectors in the ECM or PCM circuit.
5. Faulty immobilizer control module.
Code Solutions P0633.
1. Check all immobilizer keys to ensure they are programmed and recognized by the vehicle’s ECM or PCM.
2. Use manufacturer-approved programming tools to reprogram any unprogrammed immobilizer keys.
3. Ensure that the ECM or PCM is programmed with the correct immobilizer data using manufacturer-approved programming tools.
4. Inspect the wiring and connectors associated with the ECM or PCM for damage, corrosion, or looseness. Repair or replace wiring and connectors as needed.
5. If necessary, replace the immobilizer control module if it is determined to be faulty.
6. Clear the trouble codes and test drive the vehicle to see if the P0633 code returns. If it does, further diagnosis may be necessary.