AutoCodes – Generic – P20CB

P20CB Code - Exhaust Aftertreatment Fuel Injector Control Circuit

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 Injector, Exhaust Aftertreatment Fuel Injector harness is open or shorted, Exhaust Aftertreatment Fuel 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: P20CB indicates Exhaust Aftertreatment Fuel Injector Control Circuit.
Common causes: Common causes include Faulty Exhaust Aftertreatment Fuel Injector, Exhaust Aftertreatment Fuel Injector harness is open or shorted, Exhaust Aftertreatment Fuel 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 25,690

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 Jul 27, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P20CB 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. The ECM supplies power and ground to the high and low control circuits of the exhaust aftertreatment fuel injector. When the ECM detects a fault on either of the exhaust aftertreatment fuel injector circuits it sets a Diagnostic Trouble Code (DTC).

OBDII Code P20CB - Exhaust Aftertreatment Fuel Injector Control Circuit - AutoCodes.com — P20CB Code - Exhaust Aftertreatment Fuel Injector Control Circuit

What does this mean?

What are the Possible Causes of the DTC P20CB?

Faulty Exhaust Aftertreatment Fuel Injector
Exhaust Aftertreatment Fuel Injector harness is open or shorted
Exhaust Aftertreatment Fuel Injector circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P20CB?

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 P20CB 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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Information for Specific Makes

P20CB Buick — Exhaust Aftertreatment Fuel Injector Control Circuit
P20CB Cadillac — Exhaust Aftertreatment Fuel Injector Control Circuit
P20CB Chevrolet — Exhaust Aftertreatment Fuel Injector Control Circuit
P20CB GMC — Exhaust Aftertreatment Fuel Injector Control Circuit

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.