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Engine-Codes – Generic – U2628

U2628 Code - Reductant Control Module Lost Communication With Reductant Concentration Sensor

Quick Answer

The U2628 diagnostic trouble code (DTC) indicates that there is a communication issue between the Reductant Control Module (RCM) and the Reductant Concentration Sensor (RCS) in a vehicle equipped with a Selective Catalytic Reduction (SCR) system. Common causes include Faulty Reductant Control Module, Faulty Reductant Concentration Sensor, Wiring or connection issues between RCM and RCS. 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
U2628 indicates Reductant Control Module Lost Communication With Reductant Concentration Sensor.
Common causes
Common causes include Faulty Reductant Control Module, Faulty Reductant Concentration Sensor, Wiring or connection issues between RCM and RCS.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 08, 2024
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Code U2628 Description

The U2628 diagnostic trouble code (DTC) indicates that there is a communication issue between the Reductant Control Module (RCM) and the Reductant Concentration Sensor (RCS) in a vehicle equipped with a Selective Catalytic Reduction (SCR) system. The SCR system is responsible for reducing harmful emissions by injecting a urea-based solution (diesel exhaust fluid or DEF) into the exhaust stream to convert nitrogen oxides (NOx) into harmless nitrogen and water vapor.

OBDII Code U2628 - Reductant Control Module Lost Communication With Reductant Concentration Sensor
U2628 Code - Reductant Control Module Lost Communication With Reductant Concentration Sensor

Common Causes of U2628

  1. Faulty Reductant Control Module
  2. Faulty Reductant Concentration Sensor
  3. Wiring or connection issues between RCM and RCS
  4. Software or programming issues
  5. Electrical system malfunctions

Symptoms of U2628

  1. Check engine light illuminated
  2. Reduced power or limp mode
  3. Increased emissions
  4. Failed emissions test
  5. Poor fuel economy

How to Fix U2628

  1. Use a scan tool to retrieve and record the DTCs present in the vehicle's computer system.
  2. Inspect the wiring harness and connectors between the RCM and RCS for any damage, corrosion, or loose connections.
  3. Test the Reductant Concentration Sensor using a multimeter to ensure it is functioning properly.
  4. Check for any software updates or reprogramming required for the RCM to establish communication with the RCS.
  5. If necessary, replace the faulty Reductant Control Module or Reductant Concentration Sensor.

Cost to Fix U2628

The cost of repairing a U2628 code can vary depending on the specific cause of the communication issue and the labor rates at the repair facility. In general, replacing a Reductant Control Module or Reductant Concentration Sensor can range from $200 to $600 for parts, with additional labor costs averaging between $100 and $200. However, it's important to note that prices may vary based on the vehicle make and model, as well as the location and type of repair shop. Diagnostic time and labor rates should also be considered when estimating the total repair cost.

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Code U2628 Information for Specific Makes

  • U2628 Buick — Reductant Control Module Lost Communication With Reductant Concentration Sensor
  • U2628 Cadillac — Reductant Control Module Lost Communication With Reductant Concentration Sensor
  • U2628 Chevrolet — Reductant Control Module Lost Communication With Reductant Concentration Sensor
  • U2628 GMC — Reductant Control Module Lost Communication With Reductant Concentration Sensor
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 U2628 Code

1. What are the common symptoms of OBDII code U2628?

The common symptoms of code U2628 include the check engine light illuminating on the dashboard, reduced engine performance, and potential issues with the vehicle's emissions system.

2. What causes the OBDII code U2628 to appear?

This code typically appears when there is a communication failure between the reductant control module and the reductant concentration sensor. This can be caused by wiring issues, a faulty sensor, or a malfunctioning control module.

3. How can I diagnose the cause of OBDII code U2628?

To diagnose the cause of code U2628, you can start by checking the wiring connections between the reductant control module and the concentration sensor. You can also test the sensor and control module for proper functionality using a diagnostic tool.

4. Can I drive my vehicle with OBDII code U2628?

It is not recommended to drive your vehicle with a pending or active U2628 code, as it can lead to further damage to the emissions system and potentially affect the vehicle's performance. It is best to address the issue promptly.

5. How can I repair OBDII code U2628?

Repairing code U2628 may involve replacing the reductant concentration sensor, repairing any damaged wiring, or replacing the reductant control module. It is recommended to consult a professional mechanic for an accurate diagnosis and repair.

6. Will resetting the trouble codes make OBDII code U2628 disappear?

Resetting the trouble codes may temporarily clear the U2628 code, but if the underlying issue causing the communication failure between the control module and sensor is not addressed, the code is likely to reappear.

7. Is OBDII code U2628 a serious issue?

Code U2628 is considered a moderate issue that should be addressed in a timely manner. Ignoring this code can lead to potential problems with the vehicle's emissions system and may cause the vehicle to fail an emissions test.

8. Can a DIY enthusiast fix OBDII code U2628?

While some DIY enthusiasts may have the skills to diagnose and repair issues related to code U2628, it is recommended to seek professional help, especially when dealing with intricate components like the reductant control module and concentration sensor.

9. How much does it cost to repair OBDII code U2628?

The cost of repairing code U2628 can vary depending on the specific cause of the issue, the parts needed for replacement, and the labor rates of the repair shop. It is advisable to obtain quotes from different mechanics.

10. How can I prevent OBDII code U2628 from appearing again?

To prevent code U2628 from reappearing, it is essential to address any underlying issues promptly, perform regular maintenance on the vehicle's emissions system, and ensure proper wiring connections between the control module and sensor. Regular vehicle inspections can also help catch potential problems early.

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