Incorrect Immobilizer Key

Possible causes

• CommonKey not programmed to this vehicle
• CommonFlat battery in the key, on systems that need it
• CommonDamaged transponder inside the key
• CommonOther keys or transponders on the same keyring interfering with the reader
• PossibleFaulty reader coil around the ignition barrel
• PossibleAftermarket alarm or immobiliser interfering
• PossibleImmobiliser or engine module not matched after a repair

What you might notice

• Engine turns over but will not start
• Immobiliser or key warning light
• One key works and another does not
• Intermittent failure to start

What to check, in order

1. Try the spare key. If it works, the fault is the key, not the car - and that is the cheapest outcome available.
2. Take every other key and transponder off the keyring and try again. Two transponders near the reader at once can stop either being read.
3. Replace the battery in the key if it has one.
4. Ask whether the key was recently cut or copied. A key cut mechanically but never programmed will turn the ignition and do nothing else.
5. Expect proof of ownership to be required for key programming. That restriction is deliberate.
6. Do not switch the engine off far from home until this is resolved - a car that starts today may not start again.