CASE 014
Engine Cranks But No Start — Immobilizer
expert
24 min
Diesel
Vehicle
- ModelTraining Estate 1.9
- Engine1.9 dCi
- Mileage203,000 km
Customer complaint
The engine cranks normally but will not fire, and a key/security warning is shown on the cluster.
History
The customer dropped the key recently and a spare key was used since then.
Fault codes
B1000 Immobilizer / anti-theft codeP0513 Invalid key code
Live data
- Key recognisedNot recognised
- Engine speed while crankingPresent
Measurements
- Second keyAlso not recognised
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Diagnostic case
Next step — Reasoning.
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Confirmed cause
Immobilizer authentication failure preventing the ECU from enabling injection.
Reasoning
Cranking with a present rpm signal and a valid battery is a “no enable” pattern, not a mechanical no-start. Security codes and a key that is not recognised point to the immobilizer. Because both keys fail, the fault is more likely the receiver/antenna, wiring or a module issue than a single damaged key.
Recommended repair
- Check the immobilizer receiver/antenna and its wiring.
- Diagnose the immobilizer module and communication.
- Reprogram keys only after the authentication fault is resolved, following the manufacturer procedure.
Related tools
All values shown are training examples. Real thresholds depend on the manufacturer, engine, temperature and system — always confirm with the vehicle service documentation.