P2A73 code meaning
Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit High
Powertrain system Generic code P2Axx codes Check engine light
What P2A73 means
P2A73 signals that the select valve control circuit sits at a higher voltage than the commanded state allows. Typical faults are an open coil or broken wire on a low-side driven valve, which leaves the line at supply voltage, or a short to battery voltage that the output cannot pull down. The valve then stays in its spring-return position, so hydraulic flow keeps going to one tank pump whatever the command. On a multi-tank LNG truck the second tank may never be used, and the engine runs short of gas although LNG remains on board. Caterpillar's patent shows such a valve shifted by an actuator under controller command. No manufacturer publishes P2A73. Check coil resistance, the connector and the supply wire.
P2A73 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 P2A73
- Check engine light on
- Second LNG tank not used, range clearly shorter
- Gas supply stops although fuel remains
Common causes of P2A73
- Most likelyValve coil or control wire open
- PossibleControl wire shorted to battery voltage
- Less likelyCorroded connector pins with very high resistance
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 P2A73 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. |
| 73 | The exact fault in that area. |
What to do next
- Note P2A73 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 P2A73
What does P2A73 mean?
P2A73 means "Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit High". P2A73 signals that the select valve control circuit sits at a higher voltage than the commanded state allows. It is a generic code, so it means the same on every make.
Is it safe to drive with P2A73?
Drive gently and only to a workshop. With P2A73 the car can go into limp mode (reduced power) to protect itself.
Will P2A73 fail an emissions test?
Yes, it can. P2A73 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 P2A73 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P2A73 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.