P12A1
P12A1Diagnosis information - DME (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.
- 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 more than 9 V
- Engine start recognized more than 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