P0124: Throttle or pedal position sensor A: intermittent signal

What P0124 means

The ECU needs to know how far the throttle valve (the flap that lets air into the engine) is open, or how far you are pressing the accelerator, to meter air and fuel. Which sensor counts as sensor A is decided by each manufacturer, although it is usually the throttle one. This code means the signal comes and goes: sometimes it is fine and sometimes it disappears or jumps.

Most common causes

• Loose sensor connector or corroded terminals
• Chafed wire that only makes contact with vibration or bumps
• Worn sensor track in the most used area
• Faulty throttle body with built-in sensor
• Loose or dirty engine earth

Symptoms

• Engine warning light coming on and going off
• Brief losses of power or occasional limp mode
• Jerking for no obvious reason
• Idle speed rising and falling

Can you drive with P0124?

With care You can drive, but the car may suddenly lose power when it drops into limp mode. Get it to a garage soon and avoid overtaking and fast roads in the meantime.

How to check it

With the ignition on and the engine off, watch the position in live data while you press the pedal very slowly and gently move the wiring loom: if the value jumps when you touch a certain spot, that is where the poor contact is.

How to read and clear P0124 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0124 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

• P0120 Throttle or pedal position sensor A: circuit fault
• P0121 Throttle or pedal position sensor A: out of expected range
• P0122 Throttle or pedal position sensor A: low signal
• P0123 Throttle or pedal position sensor A: high signal
• P0125 Engine takes too long to warm up for fuel mixture control
• P0128 Thermostat: coolant not reaching normal operating temperature
• P0130 Oxygen sensor (bank 1, sensor 1): circuit fault
• P0131 Oxygen sensor (bank 1, sensor 1): voltage too low
• P0100 Mass or volume air flow sensor circuit fault
• P0101 Air flow sensor range or performance problem
• P0102 Air flow sensor circuit low input
• P0103 Air flow sensor circuit high input

P0124 is a generic code, so it means the same on any make, for example on BMW, Ford, Mazda, Mercedes-Benz, Peugeot, Volkswagen. See what Final OBD does on your car in makes and models.