P01A4
Alternative Fuel Rail Pressure Sensor Performance
Alt fuel rail pressure sensor reading implausible.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Sensor reading driftedCommon
- Sensor element aged beyond calibration windowLess likely
- Sensor element contaminated by oil, soot or coolantLess likely
Parts involved
- Alt Fuel Rail Pressure Sensor
P01A4 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.