AutoCodes – Cadillac – U1549 Cadillac

U1549 Cadillac Code - Body Control Module Lost Communication With Rear Wiper Motor 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 Rear Wiper Motor, Rear Wiper Motor harness is open or shorted, Rear Wiper Motor 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: U1549 Cadillac indicates Body Control Module Lost Communication With Rear Wiper Motor On LIN Bus.
Common causes: Common causes include Faulty Rear Wiper Motor, Rear Wiper Motor harness is open or shorted, Rear Wiper Motor 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 700

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 U1549 Cadillac 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 Rear Wiper Motor has not been received.

OBDII Code U1549 Cadillac - Body Control Module Lost Communication With Rear Wiper Motor On LIN Bus - AutoCodes.com — U1549 Cadillac Code - Body Control Module Lost Communication With Rear Wiper Motor On LIN Bus

What does this mean?

What are the Possible Causes of the DTC U1549 Cadillac?

Faulty Rear Wiper Motor
Rear Wiper Motor harness is open or shorted
Rear Wiper Motor circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC U1549 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 U1549 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 U1549 Cadillac Code

1. What are the common symptoms of OBDII code U1549 in a Cadillac related to the Body Control Module losing communication with the rear wiper motor?

The common symptoms include the rear wiper not functioning, the rear wiper operating erratically, and dashboard warning lights related to the wiper system.

2. What are the possible causes of the Body Control Module losing communication with the rear wiper motor on the LIN bus in a Cadillac?

Possible causes can include a faulty rear wiper motor, damaged wiring or connectors in the LIN bus circuit, a malfunctioning Body Control Module, or software issues.

3. How can I diagnose the issue causing OBDII code U1549 in a Cadillac?

Diagnosis involves conducting a thorough inspection of the rear wiper motor, checking the wiring and connectors for any damage, testing the LIN bus communication, and using a scan tool to retrieve specific fault codes.

4. Can I still drive my Cadillac with OBDII code U1549 present?

While it may be possible to drive the vehicle, it is not recommended as the rear wiper plays a crucial role in visibility during adverse weather conditions. It is best to address the issue promptly.

5. Are there any DIY repair tips for resolving OBDII code U1549 in a Cadillac?

DIY repair tips include checking and securing the wiring connections, inspecting the rear wiper motor for any visible damage, and resetting the Body Control Module by disconnecting the battery for a few minutes.

6. Do I need specialized tools to fix the issue related to the Body Control Module losing communication with the rear wiper motor on the LIN bus in a Cadillac?

While basic tools may be sufficient for inspecting wiring and connectors, diagnosing and repairing LIN bus communication issues may require specialized diagnostic tools and equipment.

7. How much does it typically cost to repair OBDII code U1549 in a Cadillac at a dealership or repair shop?

The cost of repair can vary depending on the specific cause of the issue. It is advisable to consult with a dealership or repair shop for a detailed diagnosis and cost estimate.

8. Is OBDII code U1549 in a Cadillac a common issue, or is it specific to certain models or years?

This code can occur in various Cadillac models with rear wiper systems and LIN bus communication. However, the frequency of occurrence may vary based on the specific vehicle and its age.

9. Can ignoring OBDII code U1549 lead to other problems in my Cadillac?

Continued operation with this issue unresolved may lead to further electrical malfunctions, potential damage to the rear wiper system components, and compromising the safety of the vehicle in certain driving conditions.

10. After repairing OBDII code U1549 in a Cadillac, should I reset the fault codes and clear the Check Engine light?

Once the issue is fixed, it is recommended to reset the fault codes using a scan tool and clear the Check Engine light to ensure the system registers the repair and monitors the vehicle's performance accurately.