What it means
The TPS signal shows intermittent dropouts that do not stay outside threshold long enough to trigger P0122/P0123. Drive-by-wire systems are sensitive to this and may briefly enter limp-home mode each time.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Throttle or pedal position sensor A reports position through a signal circuit that the module monitors for continuity and smooth movement. P0124 sets when that signal drops out or becomes erratic intermittently, even if it does not remain out of range long enough to set a low-input or high-input code.
Common causes
Most likely first.
- Loose or oxidised connector
- Sensor track worn at one spot (older potentiometer-type)
- Connector with intermittent contact under vibration
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 graph sensor A live data while slowly operating the pedal or throttle, looking for brief dropouts.
- Inspect the sensor A connector for oxidation, looseness, damaged terminals, or signs that vibration could interrupt contact.
- Check the harness for chafing or strain, then gently move sections while monitoring the signal for interruptions.
- Compare sensor A with its paired position signal to determine whether the dropout is limited to one circuit.
- Test the sensor and wiring for intermittent continuity or signal loss against the manufacturer's specification.
Common fixes
- Secure a loose sensor connector and clean corrosion from its terminals.
- Repair chafed or strained wiring in the sensor A circuit.
- Replace damaged connector terminals that lose contact under vibration.
- Replace the position sensor if its signal drops out during testing.
Can I keep driving?
Intermittent throttle response can cause hesitation or brief power loss, and limp mode may occur when the fault returns. Keep journeys short and avoid fast traffic until the connection or sensor fault is repaired.
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.