AutoCodes – Cadillac – U1066 Cadillac

U1066 Cadillac Code - Loss Of Communication With Rear Integrated Module

Quick Answer

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Common causes include Faulty Rear Integrated Module (RIM), Rear Integrated Module harness is open or shorted, Rear Integrated 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: U1066 Cadillac indicates Loss Of Communication With Rear Integrated Module.
Common causes: Common causes include Faulty Rear Integrated Module (RIM), Rear Integrated Module harness is open or shorted, Rear Integrated 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.

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Code Popularity 1,952

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 22, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1066 Cadillac Description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for the state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a Diagnostic Trouble Code (DTC) U1066 is set.

OBDII Code U1066 Cadillac - Loss Of Communication With Rear Integrated Module - AutoCodes.com — U1066 Cadillac Code - Loss Of Communication With Rear Integrated Module

What does this mean?

What are the Possible Causes of the DTC U1066 Cadillac?

Faulty Rear Integrated Module (RIM)
Rear Integrated Module harness is open or shorted
Rear Integrated Module circuit poor electrical connection

How to Fix the DTC U1066 Cadillac?

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 U1066 Cadillac 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 U1066 Cadillac Code

1. What are the common symptoms of OBDII code U1066 in a Cadillac related to loss of communication with the Rear Integrated Module?

The common symptoms include non-functioning rear lights, issues with rear wipers, problems with rear parking sensors, and malfunctioning rear climate control.

2. What are the possible causes of OBDII code U1066 in a Cadillac?

The code U1066 is typically triggered by a faulty Rear Integrated Module, damaged wiring or connectors, a blown fuse, or a communication error within the vehicle's network.

3. How can I diagnose the cause of OBDII code U1066 in my Cadillac?

You can start by checking the wiring and connectors related to the Rear Integrated Module, inspecting the fuses, using a diagnostic scan tool to communicate with the module, and conducting a visual inspection for any visible damage.

4. Is it safe to continue driving my Cadillac with the U1066 code triggered?

It is not recommended to drive your Cadillac with the U1066 code triggered, as it can lead to issues with vital rear systems like lights and wipers, compromising your safety on the road.

5. How can I reset the OBDII code U1066 in a Cadillac after repairing the issue?

Once you have fixed the underlying cause of the communication loss with the Rear Integrated Module, you can reset the code using an OBDII scanner or by disconnecting the car's battery for a few minutes.

6. Can a DIY enthusiast repair the OBDII code U1066 issue in a Cadillac?

Depending on your skill level and access to tools, you may be able to repair the U1066 code issue by checking and fixing wiring connections, replacing damaged components, or resetting the module. However, for complex issues, professional help may be required.

7. What are some tips to prevent the recurrence of OBDII code U1066 in a Cadillac?

To prevent the code from reoccurring, regularly check the condition of the wiring and connectors, ensure proper maintenance of the Rear Integrated Module, and address any electrical issues promptly.

8. Will fixing the OBDII code U1066 in my Cadillac be expensive?

The cost of repairing the U1066 code can vary depending on the root cause of the issue. Simple fixes like replacing a blown fuse may be relatively inexpensive, while replacing the Rear Integrated Module can be more costly.

9. Can extreme weather conditions cause the OBDII code U1066 in a Cadillac?

Extreme weather conditions can potentially affect the electrical components of your Cadillac, leading to communication errors with the Rear Integrated Module and triggering the U1066 code. Regular maintenance can help prevent such issues.

10. How long does it typically take to repair the OBDII code U1066 issue in a Cadillac?

The repair time for the U1066 code can vary based on the complexity of the problem. Simple fixes like reconnecting a loose wire may take a short time, while diagnosing and replacing a faulty Rear Integrated Module can be more time-consuming.