Toyota Aygo - Fault code P0420, P0300 misfires or engine starts poorly
| Data sheet | |
| Manufacturer | Toyota |
| Vehicle model | Aygo |
| Year of manufacture | 2005 – 2012 |
| Engine | 1.0i (1KR-FE) |
| Fault codes | P0420 (catalytic converter efficiency) or P0300 or P0301/302/303 (combustion misfire, cylinders 1-3) |
| Symptoms | Engine control lamp lights up | Misfiring | Engine starts poorly |
Toyota Aygo - Oil carbon deposits on the spark plugs
Oil carbon deposits on the spark plugs can lead to the following problems in the vehicles mentioned above:
- Misfires
- Poor starting behaviour
- The engine control lamp is lit up
- Fault codes stored in the control unit
Firstly, the fault memory of the engine control unit should be read out. If the fault codes P0420 (catalytic converter efficiency) or P0300 or P0301/302/303 (combustion misfire, cylinders 1-3) are stored here, this indicates oil carbon deposits on the spark plugs.
To eliminate the problem, check the catalytic converter and the lambda sensor. If no fault is found here, it is advisable to also check the compression when subsequently replacing the spark plugs. Also make sure that the correct engine oil has been used.
After completing the work, the fault memory must be deleted.
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