P2A70Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Some heavy-duty LNG systems do not drive the cryogenic tank pump directly but through hydraulics: an engine- or motor-driven hydraulic pump supplies oil to a reciprocating hydraulic drive on each tank pump. Westport's patent US8726785B2 shows two LNG vessels whose pumps sit inside the tanks, plus a selector valve that the controller switches to decide which pump receives hydraulic flow. P2A70 covers the electrical control circuit of such a select valve and is set when the driver output detects a general fault. If the valve cannot be commanded, the system may be stuck on one tank or lose LNG supply. No manufacturer publishes P2A70; CARB's heavy-duty rule requires output components to be monitored. P2A72 and P2A73 separate the low and high cases.
- What you may notice
- Check engine light on
- Fuel drawn from one LNG tank only, range reduced
- Loss of gas supply, dual-fuel engine falls back to diesel-only or derates
- Likely causes
- LikelyDamaged harness or connector at the select valve on the frame
- PossibleSelect valve solenoid coil faulty
- RareOutput stage in the controlling module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.