AutoCodes – GMC – U1548 GMC

U1548 GMC Code - Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus

Quick Answer

The Local Interconnect Network (LIN) Bus consists of a single wire with a transmission rate of 10.417 Kbit/s. Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window Switch 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: U1548 GMC indicates Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus.
Common causes: Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window Switch 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 2,934

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 Jun 04, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1548 GMC Description

The Local Interconnect Network (LIN) Bus consists of a single wire with a transmission rate of 10.417 Kbit/s. The serial data is transmitted over a LIN circuit between a master control module and other LIN devices within a particular subsystem. If serial data communication is lost between any of the LIN devices on the LIN bus network, the master control module will set a no communication code against the non-communicating LIN device. The Diagnostic Trouble Code (DTC) will set when a supervised periodic message to the Body Control Module (BCM) from the Left Rear Window Switch has not been received.

OBDII Code U1548 GMC - Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus - AutoCodes.com — U1548 GMC Code - Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus

What does this mean?

What are the Possible Causes of the DTC U1548 GMC?

Faulty Left Rear Window Switch
Left Rear Window Switch harness is open or shorted
Left Rear Window Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC U1548 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 U1548 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 U1548 GMC Code

1. What are the common symptoms of OBDII code U1548 GMC?

The common symptoms include the left rear window not functioning, issues with the power door locks, and warning lights on the dashboard related to the body control module.

2. What causes the OBDII code U1548 GMC to appear?

This code indicates that the body control module has lost communication with the left rear window switch on the LIN bus, which could be caused by a faulty window switch, wiring issues, or a malfunctioning body control module.

3. How can I diagnose the U1548 GMC code?

Diagnosis typically involves checking the left rear window switch for proper operation, inspecting the wiring for any damage or loose connections, and testing the body control module for communication issues using a diagnostic scanner.

4. Can I still drive my vehicle with the U1548 GMC code present?

While the code itself may not directly affect the drivability of the vehicle, it's important to address the underlying issue causing the code to prevent further complications with the window switch or other related systems.

5. How do I repair OBDII code U1548 GMC?

Repair options may include replacing the left rear window switch, repairing any damaged wiring, or reprogramming the body control module. It's recommended to consult a professional mechanic for an accurate diagnosis and repair.

6. Is it possible to reset the U1548 GMC code without fixing the issue?

Resetting the code without addressing the root cause may temporarily clear the code, but it will likely reappear until the underlying problem is resolved.

7. Can a DIY enthusiast fix the U1548 GMC code at home?

Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to diagnose and repair the U1548 code at home. However, complex electrical issues may require professional assistance.

8. How much does it typically cost to repair OBDII code U1548 GMC?

The cost of repairing this code can vary depending on the cause of the issue, parts needed for replacement, and labor rates. It's advisable to obtain multiple quotes from different mechanics or repair shops.

9. Are there any preventive measures to avoid OBDII code U1548 GMC in the future?

Regularly inspecting and maintaining the window switches, wiring harnesses, and body control module can help prevent issues that may lead to the U1548 code. Additionally, addressing any electrical problems promptly can help avoid further complications.

10. Can the U1548 GMC code affect other systems in the vehicle?

While this code specifically relates to the communication between the body control module and the left rear window switch, it's possible for related systems like power door locks or other window switches to be affected if the issue is left unresolved.