OBD-II trouble code
P0124: Throttle/Pedal Position Sensor 'A' Circuit Intermittent
The throttle position signal is cutting in and out — dropping or spiking for an instant and then recovering. Classic sign of a worn sensor or a loose connection.
Quick facts
- System
- Powertrain
- Category
- Throttle / Idle
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $500
- DIY difficulty
- Intermediate DIY
Browse every code in P0100–P0199, or start from the full code library.
What does P0124 mean?
The throttle position sensor (TPS) tells the engine computer how far the throttle is open; on drive-by-wire vehicles the same code family also covers the accelerator pedal position sensor. P0124 sets when the "A" circuit signal is intermittent — it momentarily drops out, spikes, or jumps in a way a real throttle movement can't explain, then returns to normal. That's what distinguishes it from P0122 (signal stuck low) and P0123 (stuck high).
An intermittent signal has two families of cause and they are worth keeping apart, because they cost very different amounts. The connection family — a loose or corroded connector terminal, a spread pin, a chafed wire that touches ground or opens over bumps, a poor sensor ground — is the cheap one, and it is the one to rule out first because the repair is a terminal or a length of wire. The component family is a worn spot on an older sensor's resistive track, which is a real failure mode on cable-throttle vehicles with a wiping-contact TPS but costs a sensor or a throttle body to fix. Because the fault comes and goes, it may not be present when you test — which is why a wiggle test while watching live data is the key diagnostic move.
On drive-by-wire vehicles the computer treats implausible throttle data seriously: expect reduced-power (limp) mode, and the fault may feel like random hesitation, surging, or an engine that briefly cuts as you drive.
Common causes
- Loose, corroded, or backed-out connector terminal
- Chafed or intermittently open/shorted signal wire
- Poor sensor ground or unstable 5-volt reference
- Worn throttle/pedal position sensor with a dead spot on the track — a genuine failure mode, but a sensor or throttle body to fix, so prove the wiring first
- Throttle body or pedal assembly fault on drive-by-wire vehicles
Symptoms
- Check engine light on (may be intermittent)
- Random hesitation, stumble, or surging
- Momentary loss of throttle response
- Reduced power / limp mode on drive-by-wire vehicles
- Erratic idle or harsh shifting
Diagnostic steps
- 1.Scan codes and freeze-frame; note conditions when the fault sets (bumps, temperature, throttle angle).
- 2.Watch TPS/APP voltage on live data while slowly sweeping the signal through its range — open the throttle by hand on a cable-throttle vehicle, but use the accelerator pedal on a drive-by-wire one. Do not lever a drive-by-wire throttle plate open by hand: the plate is driven through a geartrain by the throttle motor and forcing it is a way to turn a connector fault into a throttle body.
- 3.Perform a wiggle test on the harness and connector while watching the signal.
- 4.Inspect the connector for corrosion, spread terminals, or a loose lock.
- 5.Check 5-volt reference and ground stability at the sensor.
- 6.Replace the sensor or throttle body/pedal assembly if the signal glitches with wiring verified good; perform any required relearn.
Repair cost
$100 – $500
A standalone TPS is cheap ($30-$100) where serviceable. On drive-by-wire vehicles the sensor is often integrated into the throttle body ($200-$500 installed) or pedal assembly. Connector repairs are inexpensive and fix many intermittent codes.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with throttle body replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.