Throttle Position Sensor (TPS) Circuit Intermittent
What does P0124 mean?
The P0124 code means the vehicle's onboard diagnostic system has detected: Throttle Position Sensor (TPS) Circuit Intermittent. This is a moderate severity code.
Common Symptoms
- Check Engine Light on, may be intermittent
- Erratic or surging idle speed
- Hesitation or jerking during acceleration
- Engine may momentarily cut power or surge
- Transmission may shift erratically (automatic)
Probable Causes (Ranked by Likelihood)
- Worn or failing throttle position sensor Very High
- Loose or corroded TPS connector High
- Damaged wiring in the TPS circuit Moderate
- Carbon buildup on throttle blade affecting sensor readings Moderate
- Faulty electronic throttle body (drive-by-wire vehicles) Low
Step-by-Step Diagnostic Procedure
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With key on engine off, slowly open the throttle while monitoring TPS voltage on a scan tool. Voltage should sweep smoothly from 0.5V (closed) to 4.5V (wide open). Any dropouts or spikes indicate a worn sensor.
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Wiggle the TPS connector while monitoring voltage. Signal changes indicate a loose or corroded connector.
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Inspect the TPS connector for bent, corroded, or pushed-back pins. Clean with electrical contact cleaner.
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On drive-by-wire vehicles, check for carbon buildup on the throttle plate. Clean with throttle body cleaner if needed.
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Check the 5V reference voltage and ground at the TPS connector with the sensor disconnected. Both should be stable.
Frequently Asked Questions
Can I drive with code P0124?
You can drive short distances at low speeds, but an intermittent TPS signal can cause sudden power surges, hesitation, or erratic shifting. The vehicle may go into limp mode. Drive cautiously to a repair shop.
What is the difference between P0121 and P0124?
P0121 indicates the TPS signal is out of expected range, suggesting a consistent problem. P0124 indicates the signal is intermittent -- cutting in and out -- which usually points to a worn sensor, loose connector, or damaged wiring.
Can I adjust a throttle position sensor?
On older vehicles with cable-operated throttle, the TPS can sometimes be adjusted by loosening its mounting screws and rotating it. On modern drive-by-wire vehicles, the TPS is built into the throttle body and requires replacement of the entire unit.