What are the common causes of P20E7?

A restriction in the reductant injection air supply line. A failed reductant injection air pressure sensor. A failed reductant injection air pump. A restriction in the exhaust system raising backpressure.

Read reductant injection air pressure on a scan tool. Check the air supply line for a restriction. Test the air pressure sensor against a gauge. Check the exhaust for a restriction. Replace the air pressure sensor if the gauge agrees. Clear the code and retest.

P20E7

Reductant Injection Air Pressure Too High

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

What it means

P20E7 means Reductant Injection Air Pressure Too High.

Check these first

A restriction in the reductant injection air supply line
A failed reductant injection air pressure sensor
A failed reductant injection air pump
A restriction in the exhaust system raising backpressure

What to do next

Read reductant injection air pressure on a scan tool
Check the air supply line for a restriction
Test the air pressure sensor against a gauge
Check the exhaust for a restriction
Replace the air pressure sensor if the gauge agrees
Clear the code and retest

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Updated

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