What it means
Intermittent signal from alt fuel tank A pressure sensor. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
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 sends a signal representing pressure in the vehicle's CNG, LPG, or hydrogen tank. The control module monitors the signal for stable, plausible changes. This code sets when the signal becomes intermittent or erratic, often because a connector or wire loses contact with vibration.
Common causes
Most likely first.
- Connector loose or corroded
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check-engine light may come on intermittently
- Alternative-fuel pressure reading may fluctuate or drop out
- Alternative-fuel system warning may appear
How to diagnose it
- Save freeze-frame data and review tank A pressure live data for sudden drops, spikes, or dropouts while the code is present.
- Following the manufacturer's fuel-system safety instructions, inspect the tank A sensor connector for looseness, corrosion, water entry, or pushed-back pins.
- Check the harness where it passes near vibrating, hot, or moving parts for chafing or strain.
- With scan data visible, gently move accessible wiring and connector sections to see whether the pressure signal changes, avoiding fuel-system components that should not be disturbed.
- If the connection and harness are sound, test the sensor output and circuit continuity using the manufacturer's procedure.
Common fixes
- Secure a loose tank A pressure sensor connector.
- Clean corroded terminals and repair connector pin damage.
- Reroute or repair wiring chafed by a vibrating component.
- Replace the sensor if its signal remains erratic with a sound circuit.
Can I keep driving?
Driving may be possible if the vehicle runs normally, but the tank pressure reading can drop out and trigger a fuel-system warning. Stop and follow the vehicle's safety instructions if a warning requires shutdown or you suspect a leak.
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.