AutoCodes – GMC – U0103 GMC

U0103 GMC Code - Lost Communication With Shift Lever Module

Quick Answer

Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Shift Lever Module, Shift Lever Module harness is open or shorted, Shift Lever 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: U0103 GMC indicates Lost Communication With Shift Lever Module.
Common causes: Common causes include Faulty Shift Lever Module, Shift Lever Module harness is open or shorted, Shift Lever 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 708

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 Mar 30, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0103 GMC Description

Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Shift Lever Module has not been received.

OBDII Code U0103 GMC - Lost Communication With Shift Lever Module - AutoCodes.com — U0103 GMC Code - Lost Communication With Shift Lever Module

What does this mean?

What are the Possible Causes of the DTC U0103 GMC?

Faulty Shift Lever Module
Shift Lever Module harness is open or shorted
Shift Lever Module circuit poor electrical connection

How to Fix the DTC U0103 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 U0103 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 U0103 GMC Code

1. What are the common symptoms of OBDII code U0103 in a GMC indicating lost communication with the shift lever module?

- Common symptoms include issues with shifting gears, warning lights on the dashboard, and potential immobilization of the vehicle.

2. What are some possible causes of OBDII code U0103 in a GMC?

- Common causes include a faulty shift lever module, damaged wiring or connectors, software issues, or a malfunctioning powertrain control module (PCM).

3. How can I diagnose the cause of OBDII code U0103 in my GMC?

- Diagnosing the issue typically involves using a professional OBDII scanner to retrieve the specific trouble codes, checking the wiring and connectors for any damage, and testing the shift lever module for functionality.

4. Can I repair OBDII code U0103 in my GMC myself, or do I need to take it to a professional mechanic?

- The repair process for this code can vary in complexity, so it's recommended to consult with a professional mechanic for an accurate diagnosis and appropriate repair plan.

5. Is it safe to continue driving my GMC with OBDII code U0103 present?

- It is not recommended to drive your vehicle with this code active, as it can lead to potential safety issues and further damage to the vehicle's components.

6. How much does it typically cost to repair OBDII code U0103 in a GMC?

- The cost of repairs can vary depending on the specific cause of the issue, but it's advisable to budget for diagnostic fees, parts replacement costs, and labor charges.

7. Can resetting the OBDII code U0103 in my GMC make it go away permanently?

- Resetting the code may temporarily clear it, but if the underlying issue causing the communication loss is not addressed, the code is likely to reappear.

8. Are there any preventive maintenance tips to avoid encountering OBDII code U0103 in a GMC?

- Regularly inspecting and maintaining the vehicle's electrical components, including the shift lever module and associated wiring, can help prevent issues leading to this code.

9. Will OBDII code U0103 in a GMC affect the vehicle's performance or fuel efficiency?

- Yes, this code can potentially impact the vehicle's performance and fuel efficiency, especially if it leads to shifting problems or other drivability issues.

10. How long does it typically take to repair OBDII code U0103 in a GMC?

- The repair time can vary based on the specific cause of the issue and the availability of parts, so it's best to consult with a mechanic for an accurate estimate.