P2A70 code meaning
Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit
Powertrain system Generic code P2Axx codes Check engine light
What P2A70 means
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.
P2A70 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2A70
- 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
Common causes of P2A70
- Most likelyDamaged harness or connector at the select valve on the frame
- PossibleSelect valve solenoid coil faulty
- Less likelyOutput stage in the controlling module faulty
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 select valveWiring harnessAfcm
What each part of P2A70 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. |
| 70 | The exact fault in that area. |
What to do next
- Note P2A70 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 P2A70
What does P2A70 mean?
P2A70 means "Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P2A70?
Drive gently and only to a workshop. With P2A70 the car can go into limp mode (reduced power) to protect itself.
Will P2A70 fail an emissions test?
Yes, it can. P2A70 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 P2A70 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P2A70 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.