P12A2

P12A2

Diagnosis information - DME V8 DFI

Fuel high-pressure sensor implausible

NOTE:
- Faults in the fuel high-pressure injection area are often caused by defects in the predelivery circuit (fuel low-pressure).
- Therefore, if there are problems in the fuel high-pressure injection area, the predelivery circuit must be checked first.

NOTE:
Diagnosis detects a permanent deviation of the measured fuel high pressure from the calculated fuel high pressure.
The fuel high pressure value is calculated from various variables such as lambda control and fuel quantity control.

Diagnostic conditions
- Battery positive voltage > 9 V
- Engine start recognized > 250 sec.
- Engine temperature - 10 °C ...+ 100 °C (50 °F ... 212 °F)
- Engine speed 450 ... 4,000 rpm
- Lambda control active

Possible fault causes
- Predelivery quantity or pressure in fuel low-pressure circuit too low
- Fuel high-pressure system leaking
- Fuel high-pressure sensor faulty
- Fuel high-pressure pump faulty