AutoCodes – GMC – P2128 GMC

P2128 GMC Code - Accelerator Pedal Position Sensor 2 Circuit High Voltage

Quick Answer

The Accelerator Pedal Assembly contains 2 Accelerator Pedal Position (APP) sensors. Common causes include Faulty Accelerator Pedal Position Sensor, Accelerator Pedal Position Sensor harness is open or shorted, Accelerator Pedal Position Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P2128 GMC indicates Accelerator Pedal Position Sensor 2 Circuit High Voltage.
Common causes: Common causes include Faulty Accelerator Pedal Position Sensor, Accelerator Pedal Position Sensor harness is open or shorted, Accelerator Pedal Position Sensor circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 5,528

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 08, 2022

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
Comments
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Code P2128 GMC Description

The Accelerator Pedal Assembly contains 2 Accelerator Pedal Position (APP) sensors. The APP sensors are mounted to the accelerator pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to the pedal position. The Engine Control Module (ECM) supplies each APP sensor with a 5 V reference circuit, a low reference circuit, and a signal circuit.
Both the APP sensors 1 and 2 signal percentages increase as the pedal is depressed, from approximately 0 percent at rest to above 95 percent when fully depressed.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the APP sensor 2 voltage is greater than 2.6 V for less than 1 s.

OBDII Code P2128 GMC - Accelerator Pedal Position Sensor 2 Circuit High Voltage - AutoCodes.com — P2128 GMC Code - Accelerator Pedal Position Sensor 2 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P2128 GMC?

Faulty Accelerator Pedal Position Sensor
Accelerator Pedal Position Sensor harness is open or shorted
Accelerator Pedal Position Sensor circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P2128 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2128 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P2128 GMC code?

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Information for Specific GMC Models

P2128 2014 GMC Sierra — Accelerator Pedal Position Sensor 2 Circuit High Voltage
P2128 2015 GMC Sierra — Accelerator Pedal Position Sensor 2 Circuit High Voltage
P2128 2016 GMC Sierra — Accelerator Pedal Position Sensor 2 Circuit High Voltage
P2128 2017 GMC Sierra — Accelerator Pedal Position Sensor 2 Circuit High Voltage
P2128 2018 GMC Sierra — Accelerator Pedal Position Sensor 2 Circuit High Voltage

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.