P1021

P1021

Diagnosis information - DME (DFI)

Fuel high-pressure quantity

NOTE:
- Faults in the fuel high-pressure injection system are often caused by defects in the pre-delivery system (fuel low-pressure).
- Therefore, if there are problems in the fuel high-pressure injection area, the predelivery circuit must be checked first.
- Diagnosis detects a deviation between required and actual values in fuel high-pressure quantity control.

Diagnostic conditions
- Battery positive voltage more than 9 V
- Engine speed between 450 rpm and 4000 rpm
- Engine temperature -10 °C ... +100 °C (14 °F ... 212 °F)
- Drive with different load and speed ranges

Possible fault causes
- Predelivery quantity or pressure in fuel low-pressure circuit too low
- Quantity control valve faulty (in fuel high-pressure pump)
- Fuel high-pressure pump faulty