P2A75 code meaning
Alternative Fuel Hydraulic Pump Pressure Sensor Circuit
Powertrain system Generic code P2Axx codes Check engine light
What P2A75 means
In a hydraulically driven LNG pump system the controller watches the oil pressure delivered by the hydraulic pump. Westport's patent US8726785B2 places this sensor in the supply line between the hydraulic pump outlet and the hydraulic drive, using it for three jobs: reversing the drive at each stroke end, spotting an empty tank when peak pressure stays low, and flagging leaks or other abnormal conditions. Caterpillar's design likewise feeds supply and return pressure to the controller to shift its directional valve. P2A75 is the general circuit fault of this hydraulic pump pressure sensor. Without the signal, the pump cannot be cycled correctly and LNG delivery may stop. No manufacturer publishes P2A75; P2A77 and P2A78 cover low and high.
P2A75 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2A75
- Check engine light on
- LNG pump stops or strokes irregularly, gas pressure drops
- Dual-fuel engine runs on diesel only or with reduced power
Common causes of P2A75
- Most likelyConnector or harness at the hydraulic pressure sensor damaged
- PossibleHydraulic pump pressure sensor faulty
- Less likelySensor supply or ground disturbed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Alt fuel hyd pump pressure sensorWiring harnessAfcm
What each part of P2A75 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| A | Area: hybrid propulsion. |
| 75 | The exact fault in that area. |
What to do next
- Note P2A75 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2A75
What does P2A75 mean?
P2A75 means "Alternative Fuel Hydraulic Pump Pressure Sensor Circuit". In a hydraulically driven LNG pump system the controller watches the oil pressure delivered by the hydraulic pump. It is a generic code, so it means the same on every make.
Is it safe to drive with P2A75?
Drive gently and only to a workshop. With P2A75 the car can go into limp mode (reduced power) to protect itself.
Will P2A75 fail an emissions test?
Yes, it can. P2A75 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2A75 to fix?
Difficulty: hard. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will P2A75 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.