What it means
The alternative fuel hydraulic pump pressure sensor circuit has a fault, so the control module may not be able to read pressure correctly.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The alternative-fuel hydraulic pump pressure sensor reports pump pressure to the control module through an electrical circuit. P2A75 sets when the sensor circuit has a fault that prevents the module from reading pressure reliably, potentially limiting alternative-fuel operation.
Common causes
Most likely first.
- Pressure sensor failed
- Wiring or connector fault
Symptoms
- Check-engine or alternative-fuel system warning light
- Reduced power or limited alternative-fuel operation
- Rough running or hesitation
How to diagnose it
- Record freeze-frame data and related codes, then compare the pressure reading with pump operation at the time the fault occurred.
- Inspect the hydraulic pump pressure sensor connector and wiring for damage, corrosion, loose pins, or fluid contamination.
- Use live scan data to check whether the pressure reading is missing, fixed, or implausible as pump operation changes.
- Test the sensor circuit wiring, reference supply, ground, and signal using the wiring diagram and manufacturer's procedure.
- Test the pressure sensor itself if its circuit checks pass, and compare its output with the manufacturer's specification.
Common fixes
- Reconnect and secure the pressure sensor connector.
- Repair damaged or corroded sensor wiring or terminals.
- Replace the pressure sensor if it fails its circuit or output test.
- Restore a confirmed sensor supply or ground fault.
Can I keep driving?
Reduced power or rough running can make acceleration unreliable, so avoid hard driving and stop if the engine stalls. If another fuel mode is available and works normally, use it until the pressure reading fault is repaired.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.