What does it mean?
P1208 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Fuel Rail Pressure Signal To PCM Circuit Malfunction .
Symptoms
- Hard start or a complete no-start
- Rough idle, misfire, power loss and limp mode
- Engine cuts out during acceleration
- Rising fuel consumption and exhaust smoke on diesel engines
- Check engine lamp on with additional rail pressure or injector codes
Likely causes
- Open or shorted signal wire from the rail pressure sensor
- Loss of the 5 volt reference or the sensor ground, which usually disturbs other sensors too
- Corroded or fuel contaminated sensor connector
- Rail pressure sensor with a drifting or dead internal output
- Harness chafe where the loom passes the fuel rail or a bracket
- Damaged sensor input circuit inside the PCM
How to fix it
- Compare commanded and actual rail pressure on the scan tool with the ignition on and during cranking
- Measure the 5 volt reference and the sensor ground at the connector
- Check the signal wire for continuity to the PCM and for shorts to ground or battery
- Inspect the connector for fuel wetting, corrosion and spread terminals
- Cross-check the sensor reading against a mechanical gauge, or substitute a known good sensor, before ordering parts
- Repair chafe points in the harness, clear the codes and retest under load