AutoCodes – Generic – U1173

U1173 Code - Lost Communications With Power Roof 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 Power Roof Module (PRM), Power Roof Module harness is open or shorted, Power Roof 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: U1173 indicates Lost Communications With Power Roof Module.
Common causes: Common causes include Faulty Power Roof Module (PRM), Power Roof Module harness is open or shorted, Power Roof 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 4,570

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 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1173 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) U1173 is set.

OBDII Code U1173 - Lost Communications With Power Roof Module - AutoCodes.com — U1173 Code - Lost Communications With Power Roof Module

What does this mean?

What are the Possible Causes of the DTC U1173?

Faulty Power Roof Module (PRM)
Power Roof Module harness is open or shorted
Power Roof Module circuit poor electrical connection

How to Fix the DTC U1173?

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 U1173 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 U1173 code?

Need more information on how to fix the U1173 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1173 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1173 Buick — Lost Communications With Power Roof Module
U1173 Cadillac — Lost Communications With Power Roof Module
U1173 Chevrolet — Lost Communications With Power Roof Module
U1173 GMC — Lost Communications With Power Roof Module
U1173 Pontiac — Lost Communications With Power Roof Module

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 U1173 Code

1. What does the OBDII code U1173 mean?

U1173 indicates a loss of communication between the vehicle's Power Roof Module and other control modules on the communication network.

2. What are common symptoms of code U1173?

Symptoms may include a malfunctioning power roof, inability to open or close the roof, and possible warning lights on the dashboard.

3. What causes the U1173 code to appear?

The code can be caused by faulty wiring or connectors, a failed Power Roof Module, or issues within the vehicle's communication network.

4. Can a weak battery trigger the U1173 code?

Yes, a weak or failing battery can disrupt communication between modules and lead to this code.

5. How can I diagnose the U1173 code?

Start by inspecting all wiring and connectors related to the Power Roof Module, check for module power and ground, and use a scan tool to monitor communication signals.

6. Is it safe to drive with the U1173 code?

While the code itself may not affect drivability, it can limit the functionality of the power roof, which may be a safety concern if the roof is stuck open.

7. How is the U1173 code repaired?

Repairs may involve fixing or replacing damaged wiring or connectors, reprogramming the module, or replacing the Power Roof Module if it’s defective.

8. Can software issues cause the U1173 code?

Yes, outdated or corrupted software in the Power Roof Module or other related modules can lead to communication errors.

9. How much does it cost to fix the U1173 code?

Repair costs can vary widely, from $50 for minor wiring repairs to $500 or more if the Power Roof Module needs replacement.

10. Can I clear the U1173 code without fixing the root cause?

Clearing the code with a scan tool may temporarily remove it, but it will likely return if the underlying issue is not resolved.

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