What Does P0124 Mean?
The ECM has detected intermittent or erratic signal behavior from the throttle position sensor A circuit. The voltage is fluctuating rapidly, spiking, or momentarily dropping out of range before returning to normal. This is often caused by a TPS with a worn spot on its resistive track or a connector with an intermittent contact, creating brief glitches that the ECM's monitoring algorithm flags.
Common Causes
35%
Worn TPS with dead spot or erratic resistance zone on the carbon resistive track at a frequently used throttle angle
30%
Intermittent contact at TPS connector due to spread terminals, vibration-induced disconnection, or corroded pins
20%
Chafed TPS signal wire making intermittent contact with ground or adjacent wires during engine vibration
15%
Electromagnetic interference from ignition coils or alternator inducing noise on TPS signal wire
Diagnostic Steps
1
Use a scan tool graphing function to record TPS A voltage during steady-state cruising and slow throttle sweeps. Look for voltage spikes, dropouts, or flat spots in the signal trace.
2
Perform a wiggle test on the TPS connector and harness while monitoring the signal. Any fluctuation during physical manipulation confirms an intermittent connection.
3
Use an oscilloscope on the TPS signal wire to capture glitches that may be too fast for scan tool sampling. Look for microsecond-duration spikes or dropouts.
4
Inspect the TPS connector for spread female terminals that lack proper tension on the male pins. Use a terminal repair tool to restore proper contact tension.
5
Route the TPS signal wire away from ignition coil wires and alternator output cables. If the wire shield is damaged, repair or replace the shielded section.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The ECM has detected intermittent or erratic signal behavior from the throttle position sensor A circuit. The voltage is fluctuating rapidly, spiking, or momentarily dropping out of range before returning to normal. This is often caused by a TPS with a worn spot on its resistive track or a connector...
The most common cause of P0124 (Throttle/Pedal Position Sensor/Switch A Circuit Intermittent) is: Worn TPS with dead spot or erratic resistance zone on the carbon resistive track at a frequently used throttle angle
Typical repair costs for P0124 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Intermittent TPS faults can cause momentary surging, hesitation, or sudden entry into reduced power mode during driving. These unpredictable events are particularly dangerous during highway driving or while navigating intersections.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0124 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Electronic Throttle Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
