What are the common causes of P20DB?

A clogged aftertreatment fuel supply line. A failed aftertreatment fuel supply control valve held open. An open or short in the fuel supply control circuit. A calibration fault in the ECM.

Command the exhaust aftertreatment fuel supply control valve on a scan tool. Check the fuel supply line for a clog. Test the fuel supply control circuit. Replace the fuel supply control valve if it stays open. Clear the code and retest.

P20DB

Exhaust Aftertreatment Fuel Supply Control Stuck Open

System: Fuel and air metering (P code)
Lamp: Check Engine Light
Category: Powertrain - Fuel/Air Metering

What it means

P20DB means Exhaust Aftertreatment Fuel Supply Control Stuck Open.

Check these first

A clogged aftertreatment fuel supply line
A failed aftertreatment fuel supply control valve held open
An open or short in the fuel supply control circuit
A calibration fault in the ECM

What to do next

Command the exhaust aftertreatment fuel supply control valve on a scan tool
Check the fuel supply line for a clog
Test the fuel supply control circuit
Replace the fuel supply control valve if it stays open
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.