P2A42
Alternative Fuel Tank B Pressure Sensor Range/Performance
The pressure signal of alternative fuel tank B does not match plausibility checks against tank temperature and fill level. Sensor drift.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Sensor zero driftedCommon
- Sensor mounting loose - bias offsetPossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- Alt Fuel Tank B Pressure Sensor
- Wiring Harness
- Afcm
P2A42 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.