P2A47 is not about broken wires: the tank C sensor delivers a voltage inside its window, yet the pressure it reports cannot be true. Plausible tests are a value that stays flat while the engine draws gas from tank C, one that does not rise during filling, or a clear gap to tanks A and B after a long rest, since cylinders on a common fill manifold settle to similar pressure. For scale, the bulletin SMB-169 that New Flyer issued for CNG buses expects the high-pressure gauge to read somewhere from 200 psi to 3,600 psi after refuelling. The cause can also be mechanical, such as a tank C valve that never opens (P2A27) or a closed manual valve. No manufacturer publishes P2A47 or its thresholds; CARB demands rationality monitoring of such inputs. Compare with a calibrated gauge before replacing parts.
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
- Gas level shown does not match refuelling or consumption
- Shorter driving range on gas
Most likely causes
- Tank C sensor drifted or frozen at one value
- Tank C solenoid not opening or manual valve closed
- Corroded contacts shifting the signal
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 P2A47 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- A: Hybrid or air and fuel
- 47: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2A47?
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 P2A47?
The most common causes are: tank C sensor drifted or frozen at one value; tank C solenoid not opening or manual valve closed; corroded contacts shifting the signal.
Related codes
- P2A46Alternative Fuel Tank C Pressure Sensor Circuit
- P2A48Alternative Fuel Tank C Pressure Sensor Circuit Low
- P2A49Alternative Fuel Tank C Pressure Sensor Circuit High
- P2A27Alternative Fuel Tank Shutoff Valve C Control Circuit Performance/Stuck Off
- P2A42Alternative Fuel Tank B Pressure Sensor Range/Performance
- P019FAlternative Fuel Tank A Pressure Sensor Performance
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.