AutoCodes – GMC – U1173 GMC

U1173 GMC 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 GMC 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 564

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

What does this mean?

What are the Possible Causes of the DTC U1173 GMC?

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 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 U1173 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 U1173 GMC Code

1. What are the common symptoms of OBDII code U1173 GMC (Lost Communications With Power Roof Module)?

- Common symptoms include the power roof not operating, malfunction indicator light (MIL) illumination, and communication errors with the power roof module.

2. What are the possible causes of OBDII code U1173 GMC?

- The code can be caused by issues such as a faulty power roof module, damaged wiring or connectors, a weak battery, or a communication network problem.

3. How can I diagnose the source of the U1173 GMC code?

- To diagnose the code, you may need to check the power roof module for proper operation, inspect wiring for damage, test connectors for corrosion, and use a diagnostic scan tool to analyze communication signals.

4. Can a weak battery trigger code U1173 GMC?

- Yes, a weak or failing battery can disrupt communication between modules in the vehicle, leading to the U1173 code. It is advisable to ensure the battery is in good condition during diagnosis.

5. What are some repair tips for resolving OBDII code U1173 GMC?

- Repair tips include checking and repairing any damaged wiring or connectors, replacing a faulty power roof module, ensuring a stable power supply, and resetting the code after repairs.

6. Is it safe to continue driving with code U1173 GMC present?

- While the vehicle may still be operable with this code, it is recommended to address the issue promptly to prevent further complications and ensure the proper functioning of the power roof system.

7. Can a DIY enthusiast fix OBDII code U1173 GMC at home?

- Depending on their skill level and access to tools, DIY enthusiasts may be able to address simpler causes of the U1173 code, such as checking and repairing wiring or connectors. However, complex issues may require professional assistance.

8. How much does it typically cost to repair OBDII code U1173 GMC?

- The cost of repairing this code can vary widely depending on the underlying cause, parts needed for replacement, and labor rates. It is advisable to obtain quotes from reputable automotive repair shops.

9. Are there any preventive measures to avoid OBDII code U1173 GMC in the future?

- Regular vehicle maintenance, including checking the power roof system, inspecting wiring for wear, and keeping the battery in good condition, can help prevent issues that may trigger the U1173 code.

10. Can a temporary loss of communication trigger code U1173 GMC?

- Yes, a temporary loss of communication between the vehicle's modules, such as due to a loose connection or momentary interference, can trigger the U1173 code. Resetting the code may resolve the issue if it was a one-time occurrence.