Worn or contaminated track in the throttle or pedal position sensor giving dropouts; Loose, corroded or damaged connector terminals at the sensor or control unit; Chafed, stretched or broken wiring in the sensor circuit, often where it flexes; Sensor reference supply or ground fault, for example a high-resistance earth connection; Dirty or sticking throttle body affecting the throttle plate position feedback; Low or unstable system voltage from a weak battery or poor charging; Internal fault in the engine control unit.

P0124

Throttle/Pedal Position Sensor/Switch A Circuit Intermittent.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
24: FaultThe specific fault in that area

What it means

P0124 is the generic code for an intermittent fault in the throttle or pedal position sensor/switch 'A' circuit. The engine control unit saw the sensor signal drop out, spike or jump to an implausible value for a short time, then return to normal. Which physical sensor is 'A' depends on the model and engine, so check the manufacturer wiring information.

Symptoms

Engine warning light on, which may come and go
Hesitation or surging under light throttle
Intermittent loss of power or limp mode with reduced throttle response
Erratic or unstable idle speed
Occasional stalling or rough running when pulling away
Cruise control or stop-start cutting out at random

Possible causes

Worn or contaminated track in the throttle or pedal position sensor giving dropoutslikely
Loose, corroded or damaged connector terminals at the sensor or control unitlikely
Chafed, stretched or broken wiring in the sensor circuit, often where it flexeslikely
Sensor reference supply or ground fault, for example a high-resistance earth connectionpossible
Dirty or sticking throttle body affecting the throttle plate position feedbackpossible
Low or unstable system voltage from a weak battery or poor chargingpossible
Internal fault in the engine control unitrare

How to diagnose

Read all stored and pending codes and note the freeze frame data (load, rpm, voltage) to see when the fault occurred
Check for related codes on throttle, pedal, reference voltage or network faults, and follow manufacturer fault-finding if present
Inspect the sensor connector and wiring visually for damage, moisture, corrosion, bent pins and poor terminal tension
Carry out a wiggle test on the harness and connector with live data displayed, watching for signal dropouts or jumps
Watch the throttle and pedal position values while moving the pedal slowly through its full range, checking for a smooth, matching trace
Check the sensor reference supply and earth at the connector against the manufacturer specification
Test the battery and charging voltage, as low voltage can upset sensor readings
Inspect the throttle body for heavy deposits or a sticking plate, with the engine off and following the manufacturer's procedure

How to fix

Repair or replace damaged wiring and renew faulty connector terminals
Replace the throttle position sensor, throttle body assembly or accelerator pedal assembly, depending on which has the faulty sensor on your model
Restore good earth and supply connections where voltage drop is found
Clean the throttle body using the correct method for the engine, then carry out any required throttle adaptation or relearn
Repair the battery or charging system if voltage is unstable
Update the control unit software only if the manufacturer lists an outdated calibration as a known cause

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but fix it soon because the throttle may cut out or go into limp mode without warning. Avoid driving if the throttle response is erratic or the engine stalls, as this can be unsafe in traffic.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.