P2A4AAlternative Fuel Tank C Pressure Sensor Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Unlike P2A48 or P2A49, which describe a signal stuck out of range, P2A4A covers a tank C pressure value that flickers: brief spikes, gaps or steps that no gas cylinder could produce, since pressure in a large tank changes only slowly. Vibration is the usual trigger, acting on a connector with weak pin tension, a cable clip that has let go, or water creeping past a seal near the back of the vehicle, where tank C often sits. A sensor failing internally is possible but rarer. Because the defect often vanishes in the workshop, freeze-frame data and a road test with live readings help. No manufacturer documents P2A4A; it mirrors P2A45 for tank B and P01A2 for tank A, and CARB covers such erratic inputs under its component rules.
- What you may notice
- Check engine light appearing occasionally
- Gas gauge jumps while driving
- No noticeable effect between dropouts
- Likely causes
- LikelyConnector pins at the tank C sensor with weak contact
- PossibleWater ingress at a connector seal
- PossibleHarness clip loose, cable rubbing
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.