AutoCodes – GMC – P220A GMC

P220A GMC Code - NOx Sensor 1 Supply Voltage Circuit

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 1, Nitrogen Oxides Sensor 1 harness is open or shorted, Nitrogen Oxides Sensor 1 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: P220A GMC indicates NOx Sensor 1 Supply Voltage Circuit.
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor 1, Nitrogen Oxides Sensor 1 harness is open or shorted, Nitrogen Oxides Sensor 1 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 500

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
FAQs
Comments
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Code P220A GMC 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 when the sensor supply voltage is less than 10.8 V.

OBDII Code P220A GMC - NOx Sensor 1 Supply Voltage Circuit - AutoCodes.com — P220A GMC Code - NOx Sensor 1 Supply Voltage Circuit

What does this mean?

What are the Possible Causes of the DTC P220A GMC?

Faulty Nitrogen Oxides (NOx) Sensor 1
Nitrogen Oxides Sensor 1 harness is open or shorted
Nitrogen Oxides Sensor 1 circuit poor electrical connection

How to Fix the DTC P220A GMC?

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 P220A GMC 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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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 P220A GMC Code

1. What are the common symptoms of OBDII code P220A (GMC) related to the NOx Sensor 1 Supply Voltage Circuit?

The common symptoms include the Check Engine Light (CEL) illuminating on the dashboard, reduced engine performance, and potential issues with the vehicle passing emissions tests.

2. What are some possible causes of the P220A trouble code for the NOx Sensor 1 Supply Voltage Circuit?

Potential causes may include a faulty NOx sensor, damaged wiring or connectors in the supply voltage circuit, a malfunctioning powertrain control module (PCM), or issues with the vehicle's electrical system.

3. How can I diagnose the OBDII code P220A (GMC) related to the NOx Sensor 1 Supply Voltage Circuit?

Diagnosis typically involves using an OBDII scanner to read the code, inspecting the NOx sensor and its wiring for visible damage, checking the voltage supply to the sensor, and testing the related circuit components for proper functionality.

4. What are the recommended repair steps for fixing the P220A fault code associated with the NOx Sensor 1 Supply Voltage Circuit?

Repair may involve replacing the faulty NOx sensor, repairing or replacing damaged wiring or connectors, resetting the fault codes with a scanner after repairs, and retesting the system to ensure the issue has been resolved.

5. Can I drive my vehicle with the P220A trouble code for the NOx Sensor 1 Supply Voltage Circuit?

It is generally not recommended to drive the vehicle with unresolved OBDII trouble codes, as it can lead to further damage and potential safety hazards. It is best to address the issue promptly.

6. How much does it typically cost to repair the P220A code related to the NOx Sensor 1 Supply Voltage Circuit?

The cost of repair can vary depending on the specific cause of the issue, the labor rates in your area, and whether you choose to fix the problem yourself or take it to a professional mechanic. Costs may range from a few hundred to a thousand dollars.

7. Are there any DIY tips for troubleshooting the P220A fault code for the NOx Sensor 1 Supply Voltage Circuit?

DIY enthusiasts can start by checking the sensor wiring and connectors for visible damage, ensuring the sensor is securely mounted, and using an OBDII scanner to reset the codes after making any necessary repairs.

8. How critical is it to address the P220A trouble code associated with the NOx Sensor 1 Supply Voltage Circuit promptly?

It is important to address OBDII trouble codes promptly to prevent potential damage to other engine components, ensure optimal vehicle performance, and avoid failing emissions tests or causing harm to the environment.

9. Can a faulty NOx Sensor 1 cause other issues in the vehicle besides triggering the P220A trouble code?

Yes, a faulty NOx sensor can lead to poor fuel efficiency, increased emissions, and potential drivability issues if left unresolved. It is crucial to address sensor-related problems promptly.

10. How long does it typically take to repair the NOx Sensor 1 Supply Voltage Circuit issue triggering the P220A fault code?

The repair time can vary depending on the exact cause of the problem, the availability of parts, and the expertise of the person performing the repairs. In general, it may take a few hours to a full day to diagnose and fix the issue.