P01A0 code meaning
Alternative Fuel Tank A Pressure Sensor Circuit Low
Powertrain system Generic code P01xx codes Check engine light
What P01A0 means
These codes only apply to vehicles that run on a gaseous alternative fuel – compressed natural gas (CNG) or LPG – either as bi-fuel models alongside gasoline (for example GM's 2015–2016 Impala Bi-Fuel or 2013–2016 Silverado/Sierra 2500HD) or as dedicated gas engines. CNG is stored at up to about 250 bar (3600 psi); a regulator reduces it to a few bar for the gas rail and injectors. The tank pressure sensor A sits at or in the regulator; together with the tank temperature it gives the gas level, and it decides whether gas operation is possible. P01A0 means the signal voltage is below its lower limit – typically a signal wire shorted to ground or open, or a missing 5 V reference. Typical reaction: gas operation is blocked and a bi-fuel vehicle switches to gasoline. No manufacturer document naming exactly this code was found; GM's bulletins only state that faults are reported like on gasoline models. The description rests on CARB, which treats such vehicles like gasoline engines for model years 2004–2018, and on the documented system design.
P01A0 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P01A0
- Check engine light on
- Gas level gauge wrong, jumping or showing empty
- Gas operation blocked or automatic switch to gasoline
- Dedicated gas engines: limp mode or starting problems possible
Common causes of P01A0
- Most likelySignal wire shorted to ground or open
- Possible5 V reference missing (open, or short in the shared 5 V circuit)
- PossibleTank pressure sensor faulty internally
- PossibleConnector at the regulator corroded
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Alternative fuel tank pressure sensorGas pressure regulatorSensor wiring
What each part of P01A0 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| A0 | The exact fault in that area. |
What to do next
- Note P01A0 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 P01A0
What does P01A0 mean?
P01A0 means "Alternative Fuel Tank A Pressure Sensor Circuit Low". These codes only apply to vehicles that run on a gaseous alternative fuel – compressed natural gas (CNG) or LPG – either as bi-fuel models alongside gasoline (for example GM's 2015–2016 Impala Bi-Fuel or 2013–2016 Silverado/Sierra 2500HD) or as dedicated gas engines. It is a generic code, so it means the same on every make.
Is it safe to drive with P01A0?
Drive gently and only to a workshop. With P01A0 the car can go into limp mode (reduced power) to protect itself.
Will P01A0 fail an emissions test?
Yes, it can. P01A0 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 P01A0 to fix?
Difficulty: hard. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will P01A0 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.