AutoCodes – GMC – U1555 GMC

U1555 GMC Code - Body Control Module Lost Communication With Left Rear Seat Heating/Venting/Cooling 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 Seat Heating/Venting/Cooling Switch, Left Rear Seat Heating/Venting/Cooling Switch harness is open or shorted, Left Rear Seat Heating/Venting/Cooling 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: U1555 GMC indicates Body Control Module Lost Communication With Left Rear Seat Heating/Venting/Cooling Switch On LIN Bus.
Common causes: Common causes include Faulty Left Rear Seat Heating/Venting/Cooling Switch, Left Rear Seat Heating/Venting/Cooling Switch harness is open or shorted, Left Rear Seat Heating/Venting/Cooling 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 801

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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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 U1555 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 Seat Heating/Venting/Cooling Switch has not been received.

OBDII Code U1555 GMC - Body Control Module Lost Communication With Left Rear Seat Heating/Venting/Cooling Switch On LIN Bus - AutoCodes.com — U1555 GMC Code - Body Control Module Lost Communication With Left Rear Seat Heating/Venting/Cooling Switch On LIN Bus

What does this mean?

What are the Possible Causes of the DTC U1555 GMC?

Faulty Left Rear Seat Heating/Venting/Cooling Switch
Left Rear Seat Heating/Venting/Cooling Switch harness is open or shorted
Left Rear Seat Heating/Venting/Cooling Switch circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC U1555 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 U1555 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.

Need more information about the U1555 GMC code?

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Need Help with the Code?

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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 U1555 GMC Code

1. What are common symptoms of OBDII code U1555 in a GMC vehicle?

- Common symptoms include malfunctioning left rear seat heating, venting, or cooling system, loss of communication with the body control module, and potential warning lights on the dashboard.

2. What causes the OBDII code U1555 GMC - Body Control Module Lost Communication With Left Rear Seat Heating/Venting/Cooling Switch On LIN Bus?

- This code is typically triggered by a communication error between the body control module and the left rear seat heating/cooling switch on the LIN bus network.

3. How can I diagnose the issue related to code U1555 GMC?

- Diagnosis usually involves checking the wiring connections between the body control module and the left rear seat heating/cooling switch, as well as testing the components for proper functionality.

4. Is it safe to continue driving with the U1555 fault code?

- While the vehicle may still be operable, it is recommended to address the issue promptly to ensure the proper functioning of the left rear seat heating/cooling system and prevent any potential electrical problems.

5. How can the U1555 GMC code be repaired?

- Repairing the U1555 code often involves inspecting and repairing any damaged wiring, ensuring proper connections, and potentially replacing the left rear seat heating/cooling switch if necessary.

6. Can a DIY enthusiast fix the U1555 code issue?

- Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to address the U1555 code by following diagnostic procedures and making necessary repairs to the wiring or components.

7. Is it necessary to reset the OBDII code U1555 after repairs are made?

- Yes, it is recommended to reset the code after repairs to clear the fault memory in the system and ensure the issue has been successfully resolved.

8. Are there any common related codes that may accompany U1555 in a GMC vehicle?

- Other related codes that may accompany U1555 include communication faults with other modules or switches in the LIN bus network, such as U1554 or U1556.

9. How can I prevent the recurrence of the U1555 code in the future?

- Regularly inspecting and maintaining the wiring and components related to the left rear seat heating/cooling system can help prevent the recurrence of the U1555 code in the future.

10. Should I seek professional help for repairing the U1555 GMC code?

- If you are unsure about diagnosing or repairing the U1555 code, it is advisable to seek professional help from a qualified mechanic or dealership to ensure the issue is properly addressed.