AutoCodes – Generic – P20D9

P20D9 Code - Exhaust Aftertreatment Fuel Supply Control Circuit Low

Quick Answer

The exhaust fuel addition injector assembly is mounted on the outlet of the turbocharger sub-assembly, and low-pressure fuel is supplied to the exhaust fuel addition injector assembly by the feed pump in the supply pump assembly. Common causes include Faulty Exhaust Aftertreatment Fuel Supply Control, Exhaust Aftertreatment Fuel Supply Control harness is open or shorted, Exhaust Aftertreatment Fuel Supply Control 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: P20D9 indicates Exhaust Aftertreatment Fuel Supply Control Circuit Low.
Common causes: Common causes include Faulty Exhaust Aftertreatment Fuel Supply Control, Exhaust Aftertreatment Fuel Supply Control harness is open or shorted, Exhaust Aftertreatment Fuel Supply Control 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 4,422

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 Jun 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P20D9 Description

The exhaust fuel addition injector assembly is mounted on the outlet of the turbocharger sub-assembly, and low-pressure fuel is supplied to the exhaust fuel addition injector assembly by the feed pump in the supply pump assembly. The exhaust fuel addition injector assembly adds fuel by a control signal from the Engine Control Module (ECM). This injector is used for two different controls: Particulate Matter (PM) forced regeneration and PM reduction.

OBDII Code P20D9 - Exhaust Aftertreatment Fuel Supply Control Circuit Low - AutoCodes.com — P20D9 Code - Exhaust Aftertreatment Fuel Supply Control Circuit Low

What does this mean?

What are the Possible Causes of the DTC P20D9?

Faulty Exhaust Aftertreatment Fuel Supply Control
Exhaust Aftertreatment Fuel Supply Control harness is open or shorted
Exhaust Aftertreatment Fuel Supply Control circuit poor electrical connection

How to Fix the DTC P20D9?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P20D9 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.

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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.