Symptoms
- No start, or cranks but won't fire
- Engine ECU not communicating with diagnostics
- P0633 stored after fitting a replacement ECU
- Replacement ECU 'restored to factory settings' elsewhere still won't program
- ECU damaged by water, or locked up after a failed remap / read attempt
Why it happens
The Bosch MD1CP017 is the engine ECU on many 2021-on JLR models. It's heavily protected, and it's tied to the car's immobiliser and security data.
They normally fail for two reasons: water ingress, or poor cracking attempts by remapping tools trying to bypass the security so the ECU can be read. A failed attempt can leave the ECU useless.
Fitting another ECU on its own isn't enough. Until it's correctly programmed and matched to the car, it will log P0633 and the engine won't run. Even a unit that's been "restored to factory settings" can still refuse to program. That's where most DIY and non-specialist attempts end.
Fault codes (DTCs)
What a diagnostic scanner typically shows. Exact codes vary with model year and scan tool.
| P0633 | Immobiliser Key Not Programmed – ECM/PCM |
On JLR MD1 ECUs, P0633 means the engine ECU and the car's security haven't been matched. Clearing the code won't help; the ECU must be programmed to the vehicle.
Models affected
| Model | Years | Code |
|---|---|---|
| Jaguar E-Pace | 2021+ | X540 |
| Jaguar F-Pace | 2021+ | X761 |
| Jaguar XE | 2021+ | X760 |
| Jaguar XF | 2021+ | X260 |
| Range Rover Evoque | 2021+ | L551 |
| Land Rover Discovery Sport | 2021+ | L550 |
| Range Rover Velar | 2021+ | L560 |
How we fix it
- Diagnose. We confirm the ECU really has failed, and that it isn't wiring, power supply or another module.
- Supply or use your ECU. A new or used MD1CP017 can be used. There's no need for the main dealer to provide a new or virginised unit.
- Program it on the car. We program the replacement without opening the ECU; it just needs the vehicle present.
- Match and test. Immobiliser matched, P0633 gone, engine started and every module checked before we leave.
Price & time
From £300 plus parts. Supplying your own used ECU? Bring it, we'll program it. Exact price confirmed before work starts. No fix, no fee.
Questions
Can a used MD1CP017 ECU be programmed to my car?
Yes. We can program a used ECU to your vehicle with the car present, without opening the ECU. You don't need a new or virginised unit from the dealer.
Why does my replacement ECU show P0633?
P0633 means the ECU hasn't been matched to the car's immobiliser. It needs programming to the vehicle; clearing the code or factory-resetting the ECU won't fix it.
How do these ECUs fail?
Mostly water ingress, or failed cracking attempts by remap tools trying to bypass the security, which can leave the ECU useless.