What it means
The control module monitors the level-sensor signal for alternative fuel tank C. It sets this code when the signal voltage falls below the expected range.
At a glance
- Usually lights the check-engine light
How it works
The tank C level sensor sends a signal to the alternative-fuel control module to indicate how much fuel remains. This circuit-low code sets when the signal voltage falls below the expected range, which can make the module read the tank incorrectly.
Common causes
Most likely first.
- Signal wire shorted to ground
- Internal sensor short
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine or alternative-fuel system warning light
- Alternative-fuel tank level or remaining range may be inaccurate
- Alternative-fuel operation may be limited
How to diagnose it
- Check freeze-frame and live data for tank C level and signal readings to confirm that the signal is low when the fault is present.
- Inspect the tank C sensor connector and harness for corrosion, damage, or a signal wire contacting ground.
- Check the sensor ground and connector terminals for excessive resistance or poor contact.
- With the circuit isolated as directed by service information, test the signal wire for a short to ground.
- Measure sensor output and circuit behavior against the manufacturer's specification to distinguish a shorted sensor from a harness fault.
Common fixes
- Clean and secure corroded or loose tank C sensor connector terminals.
- Repair a signal wire shorted to ground or damaged harness insulation.
- Restore a poor sensor ground or terminal connection.
- Replace the level sensor if it is internally shorted and fails the manufacturer's checks.
Can I keep driving?
The tank C fuel reading or remaining range may be wrong, and alternative-fuel operation can be limited. Do not count on the gauge for remaining fuel; use a conservative reserve and change fuels or stop if the vehicle begins running poorly.
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.