P0124
Throttle/Pedal Position Sensor/Switch A Circuit Intermittent
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The P0124 code specifically flags an intermittent fault in the Throttle Position Sensor (TPS) circuit. This means the ECM has detected momentary signal dropouts, spikes, or inconsistencies from the TPS that don't happen consistently enough to trigger a hard-failure code like P0122 or P0123. You may notice the Check Engine Light comes on and off, or the vehicle occasionally loses power or enters limp mode for a few seconds before returning to normal.
Intermittent TPS faults are often caused by a worn sensor with dead spots on the resistive track, or by a loose connector that loses contact during vibration. These issues can be tricky to diagnose because the fault may not be present when you're testing in the shop. Wiggling the connector and wiring while monitoring TPS voltage with a scan tool can help reproduce the fault.
Don't ignore this code even though the symptoms may seem minor or infrequent. An intermittent loss of throttle position data can cause unexpected surges or hesitations that are dangerous in traffic. The repair is usually straightforward — a new TPS sensor or connector repair. On electronic throttle vehicles, if the sensor is integrated into the throttle body, the entire assembly may need replacement. Address this within a week to prevent the intermittent issue from becoming a constant one.
Severity
Symptoms
- •Check Engine Light illuminated, may come and go
- •Sudden loss of throttle response or momentary engine hesitation
- •Vehicle may intermittently enter limp mode
- •Idle speed fluctuates without input
- •Occasional jerking or surging during steady driving
Likely Causes
As the TPS resistive element wears, small sections lose contact, causing momentary signal dropouts that the ECM detects as intermittent circuit faults.
Vibration and heat cycling can loosen the TPS connector, creating intermittent contact that causes the throttle position signal to cut in and out unpredictably.
Wires running near hot or moving engine components can develop intermittent breaks where damaged insulation allows the conductors to short or lose contact during vibration.
On drive-by-wire systems, an intermittently failing throttle body actuator motor can cause the throttle plate to momentarily lose position, triggering an intermittent fault.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace the Throttle Position Sensor (TPS)
- Inspect and reseat the TPS connector; clean terminals
- Repair or replace damaged TPS wiring harness
- Replace the electronic throttle body assembly if motor is failing