Toyota Check Engine Code
P2138 on Toyota
Throttle / Pedal Position Sensor D / E Voltage Correlation
Also covers: Lexus, Scion
P2138 on Toyota: what makes it different
Toyota's ETCS-i (Electronic Throttle Control System - intelligent) vehicles use a dual-sensor accelerator pedal assembly, and a growing voltage mismatch between the two internal pedal sensors is a well-known wear pattern that triggers P2138 on higher-mileage Camry, Corolla, and RAV4 models.
Most-affected engines
- 2AZ-FE 2.4L (Camry, RAV4)
- 2GR-FE 3.5L V6 applications
- 2ZR-FE 1.8L (Corolla)
Common model years: 2007–2015
Most likely cause on Toyota
Worn or failing accelerator pedal position (APP) sensor assembly causing the two internal pedal sensor signals to drift out of correlation.
Known Toyota engine-family issues
Toyota's accelerator pedal assemblies on ETCS-i models integrate both position sensors into a single sealed unit, so repair almost always means replacing the entire pedal assembly rather than an individual sensor.
Toyota-specific causes (most common first)
- Worn dual-sensor accelerator pedal position (APP) assembly (most common cause)
- Corroded or damaged wiring/connector at the pedal sensor harness
- Drive-by-wire throttle body position sensor drift (paired correlation fault)
- Wiring harness rub or pinch point near the pedal bracket under the dash
- Floor mat or aftermarket pedal accessory interfering with full pedal travel
- Rare PCM/ECM calibration-related correlation fault
Toyota-specific diagnostic tip
With a scan tool, graph both pedal position sensor voltage channels together while slowly pressing the pedal through its full travel — look for one channel lagging, dropping out, or diverging from the other at a specific point, which pinpoints a failing pedal sensor rather than wiring.
Symptoms drivers report
- Check engine light
- Reduced engine power / limp mode
- No throttle response
- Stalling
Typical repair cost on Toyota
Most Toyota owners fix P2138 for between $150 and $400, depending on which underlying cause turns out to be at fault. Start with the most-likely cause for your vehicle — Worn or failing accelerator pedal position (APP) sensor assembly causing the two internal pedal sensor signals to drift out of correlation. — before throwing parts at it.
Toyota P2138 FAQ
Why does my Toyota throw P2138 as it ages?
The dual-sensor accelerator pedal assembly wears over tens of thousands of presses, and the two sensor signals inside it gradually drift apart until they fail Toyota's correlation check.
Can I just replace one sensor to fix P2138 on my Camry or RAV4?
No — Toyota's pedal sensors are sealed as one assembly, so the entire accelerator pedal unit is replaced together.
Is it safe to drive with P2138 on a Toyota?
The vehicle may enter a limp/reduced-power mode for safety, so it's best to get it diagnosed and repaired promptly rather than continuing to drive normally.
Related codes
Drive a different make? See the general P2138 guide for cross-vehicle causes and symptoms.
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