AutoCodes – Generic – U1548

U1548 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 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 3,630

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

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?

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 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 U1548 code?

Need more information on how to fix the U1548 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1548 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1548 Buick — Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus
U1548 Cadillac — Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus
U1548 Chevrolet — Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus
U1548 GMC — Body Control Module Lost Communication With Left Rear Window Switch On LIN Bus

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 Code

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

The common symptoms of OBDII code U1548 include malfunctioning left rear window switch, unresponsive power windows, and issues with other related electrical components.

2. What causes the Body Control Module to lose communication with the left rear window switch on the LIN bus?

The most common causes of this issue are a faulty left rear window switch, wiring issues, a malfunctioning Body Control Module, or a communication bus fault.

3. How can I diagnose the U1548 code related to the Body Control Module and left rear window switch?

Diagnosing this code typically involves using a diagnostic scanner to read the fault codes, checking the wiring and connections for any damage, and testing the left rear window switch for proper operation.

4. Can a DIY enthusiast repair the U1548 code issue?

While some basic troubleshooting like checking fuses and connections can be done by DIY enthusiasts, diagnosing and repairing complex electrical issues related to the Body Control Module and window switch may require professional help.

5. What are some repair tips for fixing the communication loss between the Body Control Module and left rear window switch?

Repair tips include checking and repairing any damaged wiring, ensuring proper connections, replacing the faulty left rear window switch, and reprogramming or replacing the Body Control Module if necessary.

6. Are there any safety concerns associated with the U1548 code?

If the left rear window switch is malfunctioning due to the communication loss with the Body Control Module, there may be safety concerns related to the inability to operate the window in emergencies or inclement weather.

7. How urgent is it to address the U1548 code issue?

While the vehicle may still be operable with this issue, it is important to address it promptly to prevent further electrical problems and ensure the proper functioning of the left rear window switch and related components.

8. Can a disconnected or dead battery cause the U1548 code to appear?

Yes, a disconnected or dead battery can sometimes cause communication errors between the Body Control Module and the left rear window switch, triggering the U1548 fault code.

9. Is it possible for the U1548 code to be a false alarm?

In some cases, the U1548 code may be triggered by a temporary glitch or communication error. Clearing the code and retesting the system can help determine if it was a false alarm.

10. How much can it cost to repair the U1548 code issue at a professional auto repair shop?

The cost of repairing the U1548 code issue can vary depending on the underlying cause, parts needed, labor rates, and the specific shop. It is recommended to get a diagnostic and repair estimate from a trusted auto repair shop.