AutoCodes – GMC – P20E9 GMC

P20E9 GMC Code - Reductant High Pressure

Quick Answer

The pressure sensor information is used by Reductant Control Module; this module manages the reductant pressure system driving the PWM signal to the pump (corresponding to a speed setpoint for the reductant pressure pump) in order to build the pressure in the reductant pressure pipeline after the system start-up. Common causes include Faulty Reductant Injector, Reductant Injector harness is open or shorted, Reductant Injector 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: P20E9 GMC indicates Reductant High Pressure.
Common causes: Common causes include Faulty Reductant Injector, Reductant Injector harness is open or shorted, Reductant Injector 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 2,279

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 12, 2023

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
Comments
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Code P20E9 GMC Description

The pressure sensor information is used by Reductant Control Module; this module manages the reductant pressure system driving the PWM signal to the pump (corresponding to a speed setpoint for the reductant pressure pump) in order to build the pressure in the reductant pressure pipeline after the system start-up. The pressure signal is also used to control the reductant pressure in a closed loop, to supply a stable value to the reductant valve during the dosing, and to empty the reductant pressure line in After-run. The reductant pressure is monitored for pressure control governor deviation. The reductant pressure sensor signal is compared with a threshold and a pressure control governor deviation fault is reported to the Engine Control Module (ECM) after a specified time when detected. The Diagnostic Trouble Code (DTC) will be set when the Reductant Control Module detects that the reductant pressure is less than a calibrated threshold for 20 s.

OBDII Code P20E9 GMC - Reductant High Pressure - AutoCodes.com — P20E9 GMC Code - Reductant High Pressure

What does this mean?

What are the Possible Causes of the DTC P20E9 GMC?

Faulty Reductant Injector
Reductant Injector harness is open or shorted
Reductant Injector circuit poor electrical connection
Faulty Reductant Pump and Sensor Assembly

How to Fix the DTC P20E9 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 P20E9 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 P20E9 GMC code?

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Information for Specific GMC Models

P20E9 2014 GMC Sierra — Reductant High Pressure
P20E9 2015 GMC Sierra — Reductant High Pressure
P20E9 2016 GMC Sierra — Reductant High Pressure
P20E9 2017 GMC Sierra — Reductant High Pressure
P20E9 2018 GMC Sierra — Reductant High Pressure

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.

Frequently Asked Questions about P20E9 GMC Code

No Frequently Asked Questions about P20E9 GMC Code found.

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