Faulty sensor
A sensor (oxygen, temperature, pressure) can send an inconsistent value and trigger the light without affecting driving.
COMMON FAILURES01 02 03
Engine light on
The engine light indicates that an ECU has detected an anomaly. It doesn't say which one: only reading fault codes and performing checks can pinpoint it.
Possible causes
Ignition or injection
Misfires or irregular injection often result in jerks or a loss of power.
Emission control
EGR valve, particulate filter, or catalytic converter can trigger the light, sometimes with limp mode.
Price benchmarks
| Repair | Observed range |
|---|---|
| Electronic diagnostic | 50 – 80 € incl. VAT |
Prices observed in France, parts and labour included. Method and sources
Questions to ask the garage
- What fault codes were read?
- Is the fault always present or stored in the history?
- Which check confirms the part to replace?
Indicative preliminary diagnosis. Does not replace a vehicle inspection by a professional.
Describe your case
Describe your vehicle and what you observed: the analysis is based on your case.
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