P2A74 code meaning
Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit Intermittent/Erratic
Powertrain system Generic code P2Axx codes Check engine light
What P2A74 means
P2A74 covers brief, recurring faults in the select valve control circuit that clear before a firm low or high verdict. On LNG trucks the valve usually sits near the tank-mounted pump and hydraulic lines, where frame flex, road spray and very cold surfaces around the cryogenic tank stress connectors and insulation. A valve that drops out for a moment can cut hydraulic flow to the working pump mid-stroke; because Westport's control logic recognises the stroke end from pressure changes, such dropouts may also upset pump timing. Typical finds are loose terminals, corroded pins and wiring chafed along the frame rail. No manufacturer publishes P2A74. Wiggle the harness while watching the output status, and check the plug for moisture.
P2A74 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 P2A74
- Check engine light on, may go out again
- Brief hesitation or pressure dips in gas mode
- Irregular tank changeover
Common causes of P2A74
- Most likelyLoose terminal in the select valve connector
- PossibleMoisture or ice in the connector near the cryogenic tank
- PossibleHarness chafed along the frame rail with intermittent contact
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 P2A74 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. |
| 74 | The exact fault in that area. |
What to do next
- Note P2A74 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 P2A74
What does P2A74 mean?
P2A74 means "Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit Intermittent/Erratic". P2A74 covers brief, recurring faults in the select valve control circuit that clear before a firm low or high verdict. It is a generic code, so it means the same on every make.
Is it safe to drive with P2A74?
Drive gently and only to a workshop. With P2A74 the car can go into limp mode (reduced power) to protect itself.
Will P2A74 fail an emissions test?
Yes, it can. P2A74 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 P2A74 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P2A74 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.