Honda Check Engine Code
P2138 on Honda
Throttle / Pedal Position Sensor D / E Voltage Correlation
Also covers: Acura
P2138 on Honda: what makes it different
Honda's electronic throttle control system uses two accelerator pedal position sensors that must agree with each other, so P2138 (throttle/pedal position sensor correlation) is a common find as that pedal sensor assembly ages.
Most-affected engines
- K24 2.4L (Accord, CR-V)
- J35 3.5L V6 (Accord, Pilot, Odyssey)
- Other Honda drive-by-wire equipped models
Common model years: 2008–2015
Most likely cause on Honda
Worn or drifting accelerator pedal position sensor assembly
Known Honda engine-family issues
Honda's dual-sensor pedal design is meant to fail safe by disagreeing when one sensor drifts; on higher-mileage vehicles this pedal assembly (replaced as a single unit) is a known wear item that eventually triggers a correlation fault and can put the car into reduced-power mode.
Honda-specific causes (most common first)
- Internal wear in the accelerator pedal sensor assembly causing signal drift
- Corroded or damaged pedal connector/wiring
- Chafed harness near the pedal or firewall
- Electronic throttle body fault (less common, usually secondary to pedal issue)
- Voltage supply issue from the PCM to the pedal sensor circuit
Honda-specific diagnostic tip
Watch both accelerator pedal sensor voltages together on a scan tool through the full pedal travel — they should track a consistent proportional relationship; any sudden voltage jump, flat spot, or dropout points to the sensor assembly rather than the wiring or throttle body.
Symptoms drivers report
- Check engine light
- Reduced engine power / limp mode
- No throttle response
- Stalling
Typical repair cost on Honda
Most Honda owners fix P2138 for between $150 and $450, depending on which underlying cause turns out to be at fault. Start with the most-likely cause for your vehicle — Worn or drifting accelerator pedal position sensor assembly — before throwing parts at it.
Honda P2138 FAQ
Does P2138 mean I need a new throttle body on my Honda?
Usually not — this code is most often caused by the accelerator pedal sensor assembly itself, which is a separate part from the throttle body.
Why did my Honda go into reduced power mode with this code?
When the two pedal sensors disagree, the PCM can't trust the accelerator input, so it limits engine power as a safety measure until the fault is cleared.
Can a bad connection cause P2138 instead of the sensor?
Yes — always check the pedal wiring and connector for corrosion or damage before replacing the sensor assembly, since a bad connection can mimic sensor drift.
Related codes
Drive a different make? See the general P2138 guide for cross-vehicle causes and symptoms.
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