Engine

P0124 — Throttle/Pedal Position Sensor A Circuit Intermittent

Severity: medium Drive with care, to a shop

What P0124 means

The engine control unit constantly compares the signal from the throttle or accelerator pedal position sensor with what it expects. P0124 is set when the signal in circuit A drops out, jumps or goes out of range at times, then returns to normal. The PCM then cannot reliably tell how much air the engine is getting or how much power the driver wants.

Symptoms

  • Check Engine light on
  • Hesitation or surging when pressing the accelerator
  • Reduced engine power
  • Unstable or fluctuating idle
  • Random limp mode
  • Occasional stalling

Possible causes

  1. Failing throttle position sensor (TPS) or accelerator pedal position sensor (APP)
  2. Damaged wiring or corroded, loose connector pins in the sensor circuit
  3. Intermittent power or ground supply to the sensor
  4. Worn sensor track on the throttle shaft
  5. Carbon buildup making the throttle stick
  6. Internal PCM fault or software issue (rare)

How to diagnose

  1. Scan for codes and read freeze frame data to see when the fault occurred
  2. Inspect the sensor connector and harness for corrosion, chafing, moisture or bent pins
  3. Check the throttle body for carbon buildup and sticking
  4. Watch the sensor signal on a scan tool while slowly pressing the pedal; it should change smoothly with no spikes or dropouts
  5. Wiggle the harness and connector with the engine running and watch for signal changes
  6. Measure the 5 V reference and ground at the sensor connector with a multimeter
  7. Test the wires back to the PCM for continuity and shorts
  8. If wiring and supply are good, replace the sensor and suspect the PCM only last

Common fixes

  • Clean and secure connectors, repair or replace damaged wiring
  • Replace the throttle position sensor or accelerator pedal sensor
  • Clean the throttle body and perform a throttle relearn
  • Reflash or replace the PCM if it is confirmed faulty

Questions and answers

What does P0124 mean?

It means the signal from the throttle or accelerator pedal position sensor in circuit A is intermittent or unstable. The PCM notices the dropouts and stores the code.

Can I drive with P0124?

You can for a short distance if you are careful, but the engine may suddenly lose power or stall. Get it diagnosed soon.

How do I fix P0124?

Start with the sensor connector and wiring, then check the sensor's reference voltage and ground. If those are fine, the throttle or pedal sensor is usually the part to replace.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.