OBD-II trouble code
P2124: Throttle/Pedal Position Sensor 'D' Circuit Intermittent
The accelerator pedal's "D" position signal is glitching — momentary dropouts or spikes that make the computer distrust what your foot is asking for.
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
What does P2124 mean?
Drive-by-wire vehicles have no throttle cable: the accelerator pedal contains redundant position sensors (labeled D, E, and sometimes F in this code family) whose voltages tell the computer how hard you're pressing. P2124 sets when sensor D's signal is intermittent — it momentarily drops out, spikes, or steps in a way no real foot movement could produce, then recovers.
Because the throttle is entirely electronic, the computer treats implausible pedal data as a safety issue. Expect reduced-power (limp) mode, sometimes only during the glitch — which feels like the engine momentarily ignoring the pedal or surging — and a code that may be hard to reproduce in the shop.
Intermittent faults live in connections: the pedal assembly's connector, chafed harness sections between pedal and PCM, or a worn spot inside the pedal's sensor track. The wiggle test while watching both pedal sensor voltages on live data is the core diagnostic; most fixes end at the connector or with a new pedal assembly, which usually includes all its sensors.
Common causes
- Loose, corroded, or backed-out terminal at the pedal assembly connector
- Chafed or intermittently open wiring between pedal and PCM
- Worn spot/dead zone in the pedal position sensor track
- Unstable 5-volt reference or ground shared with other sensors
- Failing pedal assembly electronics
Symptoms
- Check engine light on (possibly intermittent)
- Momentary loss of throttle response or hesitation
- Reduced power / limp mode episodes
- Surging or inconsistent pedal feel
- Normal driving between events
Diagnostic steps
- 1.Record freeze-frame and note conditions when the fault sets.
- 2.Watch pedal sensor D and E voltages on live data while slowly sweeping the pedal — both should move smoothly in their defined relationship, no jumps.
- 3.Wiggle-test the pedal connector and harness while watching the signals.
- 4.Inspect the connector for corrosion and terminal tension.
- 5.Verify 5-volt reference and ground stability at the pedal.
- 6.Replace the accelerator pedal assembly if the signal glitches with wiring verified good — sensors are rarely serviceable separately.
Repair cost
$100 – $500
Connector repairs are cheap. A complete accelerator pedal assembly (the usual fix, containing all sensors) runs $80-$300 for most vehicles plus minimal labor — it's typically a few fasteners and a connector under the dash.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with accelerator pedal position sensor 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.