What it means
The outlet temperature sensor signal of alternative fuel vaporizer B 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 outlet-temperature sensor on alternative fuel vaporizer B sends a changing temperature signal to the AFCM. This code sets when that signal drops out or jumps unpredictably, pointing to an intermittent connection or unstable ground rather than a consistently low or high signal.
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
- Record freeze-frame data and check the scan tool's vaporizer B outlet-temperature reading for dropouts or sudden jumps, along with related codes.
- Inspect vaporizer B's sensor connector for an incomplete latch, loose or corroded terminals, and signs of moisture.
- Inspect the sensor harness and ground reference for chafing or looseness, then carefully move the harness while watching live temperature data for a repeatable dropout.
- Check continuity and ground stability in the vaporizer B sensor circuit using the manufacturer's wiring information, including while gently moving suspect sections of harness.
- If the connection and wiring remain sound, test the sensor for intermittent failure against the manufacturer's procedure and replace it if it fails.
Common fixes
- Fully seat and secure the vaporizer B sensor connector.
- Clean or repair loose or corroded terminals and restore a sound sensor ground connection.
- Repair damaged vaporizer B sensor wiring that loses contact with movement.
- Replace the vaporizer B outlet-temperature sensor if it fails intermittent testing.
Can I keep driving?
Avoid alternative-fuel operation if the hesitation or rough running returns, and stop somewhere safe if the engine becomes difficult to control. The AFCM may limit that fuel mode, and repeated signal dropouts can make vaporization control unreliable.
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.