AutoCodes – Mercury – U02A2 Mercury

U02A2 Mercury Code - Lost Communication With Reductant Quality Module

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Reductant Quality Module, Reductant Quality Module harness is open or shorted, Reductant Quality Module 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: U02A2 Mercury indicates Lost Communication With Reductant Quality Module.
Common causes: Common causes include Faulty Reductant Quality Module, Reductant Quality Module harness is open or shorted, Reductant Quality Module 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 650

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 Apr 07, 2020

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 U02A2 Mercury Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Reductant Quality Module has not been received.

OBDII Code U02A2 Mercury - Lost Communication With Reductant Quality Module - AutoCodes.com — U02A2 Mercury Code - Lost Communication With Reductant Quality Module

What does this mean?

What are the Possible Causes of the DTC U02A2 Mercury?

Faulty Reductant Quality Module
Reductant Quality Module harness is open or shorted
Reductant Quality Module circuit poor electrical connection

How to Fix the DTC U02A2 Mercury?

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 U02A2 Mercury 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 U02A2 Mercury code?

Need more information on how to fix the U02A2 Mercury code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U02A2 Mercury 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 U02A2 Mercury Code

1. What does the OBDII code U02A2 mean on a Mercury?

The U02A2 code indicates a "Lost Communication With Reductant Quality Module," meaning the vehicle's main computer is unable to communicate with the module that monitors the quality of diesel exhaust fluid (DEF).

2. What are the common symptoms of the U02A2 code on a Mercury?

Symptoms may include an illuminated check engine light, DEF system warnings, reduced engine performance, or the vehicle entering a "limp mode."

3. What causes the U02A2 code to appear on a Mercury?

Common causes include a faulty reductant quality module, damaged wiring or connectors, a malfunctioning CAN (Controller Area Network) bus, or a software issue in the vehicle's control module.

4. Can I still drive my Mercury with the U02A2 code?

While you may be able to drive the vehicle, ignoring the code can lead to reduced engine performance or limp mode, potentially causing further damage to the emissions system.

5. How do you diagnose the U02A2 code on a Mercury?

Diagnosis typically involves scanning the vehicle for additional codes, inspecting the wiring and connectors to the reductant quality module, and testing the CAN bus communication network.

6. What repairs are commonly needed to fix the U02A2 code on a Mercury?

Repairs may include replacing the reductant quality module, repairing damaged wiring or connectors, or updating the vehicle's software to restore communication.

7. How much does it cost to fix the U02A2 code on a Mercury?

Repair costs can vary widely, ranging from $100 to $500 or more, depending on whether the issue is related to wiring, the module itself, or other components.

8. Can a software update fix the U02A2 code on a Mercury?

Yes, in some cases, a software update to the vehicle's control module may resolve communication issues and fix the U02A2 code.

9. What happens if I ignore the U02A2 code on my Mercury?

Ignoring the code can lead to worsening DEF system performance, potential emissions violations, and the vehicle entering a restricted power mode.

10. Is the U02A2 code specific to Mercury vehicles?

No, the U02A2 code can appear on other vehicles that use a reductant quality module, but the specific diagnostic and repair steps may vary by manufacturer.