What it means
The control module compares the alternative fuel tank A pressure sensor reading with expected operating conditions. It sets this code when the reading is outside the expected range or does not behave plausibly.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Alternative fuel tank A pressure sensor measures pressure in the vehicle's CNG, LPG, or hydrogen tank. The control module checks whether the reported pressure is plausible for current operating conditions and changes as expected. This code sets when that reading is out of range or behaves implausibly, even if the circuit is electrically intact.
Common causes
Most likely first.
- Sensor reading drifted
- Sensor element aged beyond calibration window
- Sensor element contaminated by oil, soot or coolant
Symptoms
- Check-engine light on
- Alternative-fuel pressure reading may be inaccurate or unavailable
- Alternative-fuel system warning may appear
How to diagnose it
- Save the freeze-frame data and compare tank A pressure scan data with operating conditions and the manufacturer's specification.
- Inspect the tank A pressure sensor and connector for visible damage or contamination, following the manufacturer's fuel-system safety instructions.
- Check the sensor wiring and connector for corrosion, looseness, or chafing that could distort the reading.
- Compare the tank pressure signal with an independent pressure check only if the manufacturer's procedure allows it.
- If the wiring is sound and the reported pressure remains implausible, test and replace the tank A sensor if it fails the manufacturer's procedure.
Common fixes
- Clean and secure the sensor connector if contamination or looseness is found.
- Repair damaged tank A pressure sensor wiring.
- Replace a drifted or faulty alternative fuel tank A pressure sensor.
- Clear the code and verify the pressure reading tracks operating conditions.
Can I keep driving?
If the vehicle runs normally and there is no fuel-system warning, limit driving until the tank pressure reading is checked because the system may not have reliable pressure information. Stop and follow the vehicle's safety instructions if you suspect a fuel leak or receive a warning requiring shutdown.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.