AutoCodes – GMC – P2203 2018 GMC Sierra

P2203 2018 GMC Sierra Code - NOx Sensor 1 Circuit High Voltage

Quick Answer

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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: P2203 2018 GMC Sierra indicates NOx Sensor 1 Circuit High Voltage.
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 180

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 Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P2203 2018 GMC Sierra Description

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. There are two NOx sensors, one placed upstream of selective catalytic reduction, to measure inlet NOx concentration, and one placed downstream. They are connected with the control module via CAN and all the information is exchanged through it. Since it is a smart sensor, all the electrical monitoring is performed inside the sensor and only the results are sent to the Engine Control Module (ECM). Each NOx sensor contains a sensing cell, a pumping cell, and a heater. A sample of exhaust gas passes through a diffusion gap between the sensing cell and the pumping cell. The NOx sensor maintains a constant reference voltage across the sensing cell. An electronic circuit within the sensor controls the pump current through the pumping cell in order to maintain a constant voltage in the sensing cell. The amount of current required to maintain the reference voltage in the sensing cell is proportional to the concentration of NOx in the exhaust. The ECM varies the amount of diesel exhaust fluid (reductant) added by varying the reductant injector duty cycle in response to changes in engine exhaust NOx levels. The smart NOx sensors consist of two components, the NOx module and the NOx sensor element that are serviced as a unit. A circuit or performance condition with a NOx sensor is detected by the NOx sensor module. The smart NOx sensor module communicates the condition to the ECM over the serial data line. The ECM sets a DTC when a serial data message is received from the NOx sensor module. The Diagnostic Trouble Code (DTC) will be set if the ECM software detects a fault in the NOx sensor circuitry or a performance fault in the NOx sensor for greater than 2 s.

OBDII Code P2203 2018 GMC Sierra - NOx Sensor 1 Circuit High Voltage - AutoCodes.com — P2203 2018 GMC Sierra Code - NOx Sensor 1 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P2203 2018 GMC Sierra?

Faulty Nitrogen Oxides (NOx) Sensor
Nitrogen Oxides Sensor harness is open or shorted
Nitrogen Oxides Sensor circuit poor electrical connection

How to Fix the DTC P2203 2018 GMC Sierra?

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 P2203 2018 GMC Sierra 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.

Need more information about the P2203 2018 GMC Sierra code?

Need more information on how to fix the P2203 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P2203 2018 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 P2203 2018 GMC Sierra Code

What does OBDII code P2203 mean for a 2018 GMC Sierra?

Code P2203 indicates a "NOx Sensor 1 Circuit High Voltage" issue, meaning the NOx sensor in the exhaust system is detecting abnormal electrical signals.

What are the symptoms of code P2203 in a 2018 GMC Sierra?

Common symptoms include the check engine light turning on, reduced fuel efficiency, decreased engine performance, and possible issues with emissions compliance.

What causes code P2203 in a 2018 GMC Sierra?

Possible causes include a faulty NOx sensor, damaged wiring or connectors, excessive exhaust contamination, or issues with the engine control module (ECM).

Can I drive my 2018 GMC Sierra with code P2203?

Driving with code P2203 may be possible, but it is not recommended, as prolonged operation can lead to engine inefficiency and increased emissions.

How do I diagnose code P2203 in my 2018 GMC Sierra?

Diagnosis typically involves using an OBDII scanner to confirm the code, inspecting the NOx sensor and its wiring for damage, and testing the sensor's electrical connections.

How much does it cost to repair code P2203 in a 2018 GMC Sierra?

Repair costs vary but may range from $200 to $500 for parts and labor if the NOx sensor needs replacement, depending on your location and the shop.

Can a dirty exhaust system cause code P2203 in a 2018 GMC Sierra?

Yes, excessive carbon buildup or exhaust contamination can interfere with the NOx sensorâ€™s readings and trigger the code.

How do you fix code P2203 on a 2018 GMC Sierra?

Fixing the code may involve replacing the faulty NOx sensor, repairing damaged wiring, cleaning exhaust components, or updating the ECM software.

What happens if I ignore code P2203 in my 2018 GMC Sierra?

Ignoring the code can lead to worsened fuel economy, increased emissions, potential engine damage, and failure to pass state emissions tests.

What tools are needed to repair code P2203 in a 2018 GMC Sierra?

Youâ€™ll need an OBDII scanner, a multimeter for electrical testing, and basic automotive tools to inspect and replace the NOx sensor or repair wiring.