OBD-II code · Powertrain (generic, extended)
P2A78 Alternative Fuel Hydraulic Pump Pressure Sensor Circuit High
Voltage on the alternative fuel hydraulic pump pressure sensor signal line is above the expected window. Wire shorted to B+ or sensor open.
Is it safe to drive with P2A78?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelySignal wire shorted to B+
- PossibleOpen pressure sensor
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- Parts involved
- Alt Fuel Hyd Pump Pressure Sensor, Wiring Harness, Afcm
Related codes
- P2A75Alternative Fuel Hydraulic Pump Pressure Sensor Circuit
- P2A76Alternative Fuel Hydraulic Pump Pressure Sensor Range/Performance
- P2A77Alternative Fuel Hydraulic Pump Pressure Sensor Circuit Low
- P2A79Alternative Fuel Hydraulic Pump Pressure Sensor Circuit Intermittent/Erratic
- P2A7AAlternative Fuel Hydraulic Pressure Sensor Circuit
- P2A7BAlternative Fuel Hydraulic Pressure Sensor Range/Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.