P0633
Immobilizer Key Not Programmed - ECM/PCM
- Severity
- Medium
- Driving
- Short journeys only
The immobiliser key has not been programmed into the engine control module. The module and the key have to recognise each other before the engine will run, and that link has not been established - typically because the module or a key was replaced and never matched.
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
- CommonNew or replacement key never programmed
- CommonEngine module replaced without matching it to the immobiliser
What you might notice
- Engine turns over but will not start
- Immobiliser or key warning light
- One key works and another does not
- Fault present since a repair or a new key
What to check, in order
- Try the spare key. If one works, the fault is the unprogrammed key rather than the vehicle.
- Do not switch the engine off far from home until this is resolved.
- Expect proof of ownership to be required, and expect a franchised dealer or a properly equipped auto-locksmith rather than a generic tool.
- Ask what was done to the vehicle recently. These codes follow work; they do not appear on their own.
- Read the software and part numbers of the modules involved and compare them against the vehicle's build specification.
- Do not replace the module. The hardware is almost always right and the configuration is missing.
- Expect manufacturer-level programming. A generic scan tool can read these codes but cannot resolve them.
- If a used module was fitted, check whether it can be transferred to this vehicle at all - some are locked to their original VIN.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Computer output circuits and control module
P0600P0601P0602P0603P0604P0605P0606P0607P0608P0609P0610P0611P0612P0613P0614P0615P0616P0617P0618P0619P0620P0621P0622P0623P0624P0625P0626P0627P0628P0629P0630P0631P0632P0633P0634P0635P0636P0637P0638P0639P0640P0641P0642P0643P0644P0645P0646P0647P0648P0649P0650P0651P0652P0653P0654P0655P0656P0657P0658P0659P0660P0661P0662P0663P0664P0665P0666P0667P0668P0669P0670P0671P0672P0673P0674P0675P0676P0677P0678P0679P0680P0681P0682P0683P0684P0685P0686P0687P0688P0689P0690P0691P0692P0693P0694P0695P0696P0697P0698P0699