AutoCodes – Chevrolet – P221F Chevrolet

P221F Chevrolet Code - Reductant Heater 3 Current Too High

Quick Answer

The Selective Catalyst Reduction (SCR) system reduces Oxides of Nitrogen (NOx) emissions by injecting a metered amount of Diesel Exhaust Fluid (DEF) or reductant into the exhaust gas stream entering the SCR catalyst. Common causes include Faulty Reductant Heater 3, Reductant Heater 3 harness is open or shorted, Reductant Heater 3 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: P221F Chevrolet indicates Reductant Heater 3 Current Too High.
Common causes: Common causes include Faulty Reductant Heater 3, Reductant Heater 3 harness is open or shorted, Reductant Heater 3 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 895

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Sep 10, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P221F Chevrolet Description

The Selective Catalyst Reduction (SCR) system reduces Oxides of Nitrogen (NOx) emissions by injecting a metered amount of Diesel Exhaust Fluid (DEF) or reductant into the exhaust gas stream entering the SCR catalyst. Within the SCR catalyst, the reductant reacts with the NOx to form nitrogen, carbon dioxide, and water vapor. Upstream and downstream NOx sensors provide the Engine Control Module (ECM) with engine-out and tailpipe-out NOx levels in Parts Per Million (ppm). The ECM then adjusts the amount of reductant injected upstream of the SCR based on the NOx concentration. Engine-out NOx levels as measured by NOx Sensor 1 will either increase (high ppm) or decrease (low ppm) the amount of reductant injected. The NOx concentration as measured by NOx Sensor 2 provides the ECM with both an indication of the NOx conversion efficiency within the SCR as well as confirming the proper operation of the reductant system. The Diagnostic Trouble Code (DTC) will be set when the Glow Plug Control Module (GPCM) detects a heater short circuit by detecting a high current in the heater.

OBDII Code P221F Chevrolet - Reductant Heater 3 Current Too High - AutoCodes.com — P221F Chevrolet Code - Reductant Heater 3 Current Too High

What does this mean?

What are the Possible Causes of the DTC P221F Chevrolet?

Faulty Reductant Heater 3
Reductant Heater 3 harness is open or shorted
Reductant Heater 3 circuit poor electrical connection
Faulty Glow Plug Control Module (GPCM)

How to Fix the DTC P221F Chevrolet?

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 P221F Chevrolet 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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Need more information on how to fix the P221F Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

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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.

Frequently Asked Questions about P221F Chevrolet Code

What does the OBDII code P221F mean for a Chevrolet vehicle?

The P221F code indicates that the Reductant Heater 3 is detecting a current that is too high, which can affect the vehicle's emissions control system.

What are the common symptoms of the P221F code?

Common symptoms include a check engine light, reduced engine performance, increased emissions, and potential issues with starting the vehicle in cold weather.

What could cause the P221F code to trigger?

Causes may include a faulty reductant heater, wiring issues, short circuits, or problems with the engine control module (ECM) that monitors the heater.

How can I diagnose the P221F code?

To diagnose the P221F code, use an OBDII scanner to confirm the code, inspect the reductant heater and wiring for damage, and check the electrical connections for corrosion or loose connections.

What are some common repairs for the P221F code?

Common repairs include replacing the faulty reductant heater, repairing or replacing damaged wiring, and ensuring proper connections are made.

Can driving with a P221F code cause damage to my vehicle?

While it may not cause immediate damage, ignoring the code can lead to further issues with the emissions system and potentially affect engine performance over time.

Should I reset the check engine light after fixing the P221F code?

Yes, after making repairs, reset the check engine light using an OBDII scanner and monitor the vehicle to ensure the code does not return.

Is the P221F code specific to Chevrolet vehicles?

While the P221F code can occur in various vehicle makes, it is commonly associated with Chevrolet models equipped with a reductant heating system.

How much does it typically cost to repair the P221F code?

Repair costs can vary widely depending on the specific issue, but replacing a reductant heater can range from $200 to $800, including parts and labor.