Larger CNG installations, for instance on trucks or buses, may carry three or more cylinders. Where a third one, tank C, has its own pressure transducer, P2A46 reports a general electrical fault in that sensor's circuit, stored when the module finds the signal unusable but cannot classify it as too low or too high. Publicly described is only the single tank sensor of simpler systems: Ford placed it inside the regulator of its 2003 bi-fuel CNG pickups and let the AFCM derive the gauge reading from it. No manufacturer lists P2A46. In practice the first checks are the three wires at the tank C sensor, the connector seal and the shared 5 V feed; the narrower codes P2A48 and P2A49 name a low or high signal, P2A4A short interruptions.
High severity. Can I keep driving?If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
Symptoms
- Check engine light
- Remaining gas shown wrongly
- Tank C may be left unused
Most likely causes
- Wiring or plug at the tank C sensor damaged, loose or wet
- Tank C pressure sensor faulty
- Shared 5 V supply or sensor ground disturbed
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It affects emissions.
What each character of P2A46 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- A: Hybrid or air and fuel
- 46: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2A46?
If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
What causes code P2A46?
The most common causes are: wiring or plug at the tank C sensor damaged, loose or wet; tank C pressure sensor faulty; shared 5 V supply or sensor ground disturbed.
Related codes
- P2A47Alternative Fuel Tank C Pressure Sensor Range/Performance
- P2A48Alternative Fuel Tank C Pressure Sensor Circuit Low
- P2A49Alternative Fuel Tank C Pressure Sensor Circuit High
- P2A4AAlternative Fuel Tank C Pressure Sensor Circuit Intermittent/Erratic
- P2A41Alternative Fuel Tank B Pressure Sensor Circuit
- P019EAlternative Fuel Tank A Pressure Sensor Circuit
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.