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P2138 Throttle Actuator Control
Throttle/Pedal Position Sensor D/E Voltage Correlation
P2138 means the two accelerator pedal position sensors (D and E) disagree beyond an allowed range, so the ECM cannot trust the pedal signal and often forces reduced-power limp mode.
🚗 Not recommended. This code commonly forces limp mode.
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🎯 Top Causes, Ranked by Likelihood
#1 Failing accelerator pedal position sensor $100-$400
Worn dual-element pedal sensors are the most common cause.
#2 Wiring or connector fault at the pedal $50-$300
Corroded or chafed pedal wiring causes correlation faults.
#3 Poor ground or reference voltage $50-$400
A bad 5V reference or ground shifts one signal relative to the other.
#4 Faulty ECM $200-$1200
An internal ECM fault can misread the pedal signals.
🩺 Common Symptoms Reduced power / limp mode Check engine light Poor or unresponsive throttle Hesitation Surging idle 💰 Repair Cost: DIY vs Shop
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🔧 How to Diagnose P2138 1 Read live data for both pedal position signals and watch for a mismatch
2 Inspect the pedal connector and wiring
3 Test the 5V reference and ground circuits
4 Replace the accelerator pedal position sensor if signals disagree
❓ Frequently Asked Questions Can I drive with a P2138 code?
Avoid it. P2138 often forces limp mode with reduced power, which is unsafe in traffic.
How much does it cost to fix P2138?
A pedal position sensor replacement typically runs $150-$700 at a shop.
Will P2138 cause limp mode?
Yes. Because the ECM cannot trust the pedal signal, it commonly forces reduced-power limp mode.
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