P2A78

Alternative Fuel Hydraulic Pump Pressure Sensor Circuit High

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$28–89 (est.)

Symptoms

The Check Engine light comes on
Reduced engine power
Unstable engine operation
The car goes into emergency mode
Problems with switching to alternative fuels

Causes

Malfunction of the hydraulic pump pressure sensor
Open or short circuit in the sensor circuit
Alternative Fuel Hydraulic Pump Problems
Corrosion or poor contact in connectors
Engine control unit malfunction

How to Fix

Check connections and sensor wiring harness
Test the pressure sensor with a multimeter
Check alternative fuel hydraulic pump
Replace pressure sensor if necessary
Reset the code and check the system after repair

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