P2A76 is set when the hydraulic pump pressure reading looks electrically sound yet makes no sense for the operating state. Westport's patent explains why a fixed expectation is not enough: pressure rises with hydraulic pump speed, which follows engine speed when the pump is engine-driven, and with the LNG pressure the cryogenic pump works against. The controller therefore corrects its thresholds with a look-up table. A reading that stays flat while the pump strokes, shows no drop at stroke end, or disagrees with downstream fuel pressure points to a drifting sensor, but also to worn pump seals or low oil level. No manufacturer publishes P2A76 or its limits. Compare with a mechanical gauge on the test port and check the oil level.
High severity. Can I keep driving?If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
Symptoms
- Check engine light on
- Uneven LNG pressure or slow pressure build-up
- Empty-tank warning although LNG remains
Most likely causes
- Hydraulic pressure sensor drifted
- Low hydraulic oil level or external leak
- Worn hydraulic pump or drive seals
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
- It affects emissions.
What each character of P2A76 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- A: Hybrid or air and fuel
- 76: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2A76?
If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
What causes code P2A76?
The most common causes are: hydraulic pressure sensor drifted; low hydraulic oil level or external leak; worn hydraulic pump or drive seals.
Related codes
- P2A75Alternative Fuel Hydraulic Pump Pressure Sensor Circuit
- P2A77Alternative Fuel Hydraulic Pump Pressure Sensor Circuit Low
- P2A78Alternative Fuel Hydraulic Pump Pressure Sensor Circuit High
- P2A79Alternative Fuel Hydraulic Pump Pressure Sensor Circuit Intermittent/Erratic
- P2A7BAlternative Fuel Hydraulic Pressure Sensor Range/Performance
- P2A71Alternative Fuel Hydraulic Fuel Pump Select Valve Control Range/Performance
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.