What it means
The outlet temperature sensor signal of alternative fuel vaporizer C drops out or jumps intermittently. Loose connector or noisy ground.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The AFCM watches the outlet temperature signal from vaporizer C for sudden dropouts or jumps. This intermittent/erratic code sets when the reading changes inconsistently, often because the connector loses contact under vibration or the sensor ground reference is unstable.
Common causes
Most likely first.
- Sensor connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
Symptoms
- Check-engine or alternative-fuel system warning light
- Intermittent hesitation or rough running on alternative fuel
- Alternative-fuel operation may be limited
How to diagnose it
- Review freeze-frame and fault records for the operating conditions when the vaporizer C outlet-temperature signal dropped out or jumped.
- Watch the sensor's live temperature reading while gently moving the connector and accessible harness to see whether the signal changes abruptly.
- Inspect the connector seating, terminal tension, ground reference, and harness routing for looseness, corrosion, chafing, or vibration damage.
- Use the wiring diagram to check the signal and ground circuits for intermittent continuity or unwanted shorts while flexing the harness.
- If the connections remain stable, test the vaporizer C outlet-temperature sensor against the manufacturer's specification and replace it if its output is erratic.
Common fixes
- Fully seat and secure the vaporizer C sensor connector.
- Repair a loose, corroded, or vibration-damaged terminal or wire.
- Restore a sound sensor ground connection.
- Replace the sensor if its signal remains erratic with a sound harness.
Can I keep driving?
If hesitation occurs, stop relying on alternative-fuel operation and use another available fuel if the vehicle supports it. A sudden loss of temperature feedback can interrupt vaporization control and make alternative-fuel running unpredictable.
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.