What it means
Alt fuel tank A pressure sensor signal voltage below expected range. 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 voltage signal representing pressure in the vehicle's CNG, LPG, or hydrogen tank. The control module monitors that signal against the sensor circuit's expected electrical range. This code sets when the signal is too low, which can result from a grounded signal wire, a poor connection, or a faulty sensor.
Common causes
Most likely first.
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 freeze-frame data and check scan-tool data for tank A pressure and any sensor circuit status, noting whether the reading is unusually low or absent.
- Following the manufacturer's fuel-system safety instructions, inspect the tank A sensor connector and harness for corrosion, water entry, loose pins, or chafing.
- Check for a signal wire short to ground, paying particular attention to rubbed-through insulation and pinched sections.
- Measure the sensor supply, ground, and signal circuits using the wiring diagram and compare results with the manufacturer's specification.
- If the circuit tests correctly, test the tank A pressure sensor and replace it if its output remains low.
Common fixes
- Clean and secure corroded or loose tank A sensor connector terminals.
- Repair a signal wire shorted to ground or damaged harness insulation.
- Restore a poor sensor ground or supply connection.
- Replace the tank A pressure sensor if it fails the manufacturer's electrical test.
Can I keep driving?
Avoid relying on the alternative-fuel pressure display while this fault is active, and limit driving if the system warning appears or the vehicle runs poorly. Stop and follow the vehicle's fuel-system safety instructions if 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.