Fault in the high-pressure fuel rail pressure sensor circuit — relevant to the DFI 9A1 engines (987.2 only; the 987.1 M96/M97 is not direct-injected).
SYMPTOMS
- Check-engine light
- Possible rough running
- Reduced performance
- Worse fuel economy
LIKELY CAUSES
- Faulty fuel rail pressure sensor
- Open, shorted, or corroded wiring/connector
- Loss of reference voltage or ground
- ECM/PCM fault (rare)
DIAGNOSIS STEPS
- Inspect the fuel rail pressure sensor connector and wiring for damage or corrosion
- Measure sensor resistance/voltage against specification
- Check reference voltage and ground at the connector
- Compare live data to a known-good value
- Replace the sensor if out of spec
RELATED PARTS
- Fuel rail pressure sensor