Powertrain
Definition only
Lights the check engine lamp
P2A78: Alternative Fuel Hydraulic Pump Pressure Sensor Circuit High
Standardized SAE J2012 code · P2Axx codes
What does P2A78 mean?
Voltage on the alternative fuel hydraulic pump pressure sensor signal line is above the expected window. Wire shorted to B+ or sensor open.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Signal wire shorted to B+
- Medium Open pressure sensor
- Low Connector pins corroded - high contact resistance
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P2A78 on the same make and model first.
P2A78 in the community
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