What it means
Intermittent signal from throttle position sensor B (electronic throttle systems use redundant sensors).
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Throttle or accelerator-pedal position sensor B sends the PCM a signal that should remain consistent as the pedal or throttle moves. P0224 sets when the B circuit signal is intermittent, so a brief loss or disruption may trigger the code even if readings later appear normal.
Common causes
Most likely first.
- Connector loose or corroded
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
How to diagnose it
- Record freeze-frame data and check for related position-sensor codes to see whether the fault coincided with vibration, movement, or a change in throttle position.
- Graph sensor B live data while slowly moving the pedal or throttle and watch for brief dropouts or spikes.
- Inspect the B sensor connector, terminals, and nearby harness for looseness, corrosion, chafing, or contact with a vibrating or hot component.
- With the vehicle safely stationary, gently move the harness while monitoring the B signal to look for a connection that cuts in and out.
- Check the B circuit and sensor connections using the wiring diagram and manufacturer’s diagnostic procedure.
Common fixes
- Secure a loose sensor B connector and clean or repair corroded terminals.
- Repair chafed or damaged B circuit wiring and secure the harness away from rubbing or vibration.
- Replace a faulty sensor B if testing reproduces the signal dropout at the sensor.
- Perform any manufacturer-specified relearn after repair.
Can I keep driving?
Intermittent throttle response can return without warning, so avoid fast traffic and trips where a sudden loss of acceleration would be hazardous. Stop if the signal fault causes unpredictable acceleration or loss of control.
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.