DURAMAX-P2122 serious Duramax ›

Throttle/Pedal Position Sensor/Switch "D" Circuit Low Input

The DURAMAX-P2122 (Duramax) diesel fault code means: Throttle/Pedal Position Sensor/Switch "D" Circuit Low Input. This is a serious severity code.

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Keep driving?
Yes, with caution
DIY difficulty
intermediate
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What Are the Symptoms of DURAMAX-P2122?

  • Check Engine Light on
  • Reduced power mode
  • Poor or no response to the accelerator pedal

What Causes DURAMAX-P2122? (Most Likely First)

  • Failed accelerator pedal sensor High
  • Damaged wiring or a corroded connector at the pedal High
  • Shared sensor reference voltage or ground problem Moderate
  • Engine computer input fault Low

Can I Still Drive with DURAMAX-P2122?

Yes, with caution. DURAMAX-P2122 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.

Frequently Asked Questions

What does P2122 mean on a Duramax?

P2122 means Throttle/Pedal Position Sensor/Switch "D" Circuit Low Input. The pedal position sensor "D" signal is below its normal range, which usually points to a short to ground or an open supply.

Is P2122 a Duramax-specific code?

No. P2122 is a generic OBD-II code defined by SAE J2012, so it means the same thing on any vehicle that sets it. The exact conditions GM uses to set it on its diesels are in GM service information.

Mechanics Guide Step-by-step diagnosis

How Do You Diagnose DURAMAX-P2122?

  1. Find which pedal sensor is "D" on your truck in the service information. "Throttle/Pedal" codes on a diesel usually point to the accelerator pedal assembly.

  2. Inspect the pedal connector and harness.

  3. Watch sensor "D" on a scan tool while slowly pressing the pedal, looking for dropouts.

Sources 1

This page is built from documented references. Verify against your own service info before repair work.

  • SAE J2012Diagnostic Trouble Code Definitions (defines P2122 as a generic OBD-II code)

P2122 on Other Platforms

The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:

Gas / Automotive (OBD-II) Generic OBD-II definition for P2122

Explore More

More Duramax codes → Diesel home All diesel codes Heavy-duty Guides

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