AutoCodes – Generic – U0103

U0103 Code - Lost Communication With Gear Shift Control Module 'A'

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Gear Shift Control Module 'A', Gear Shift Control Module 'A' harness is open or shorted, Gear Shift Control Module 'A' 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 indicates Lost Communication With Gear Shift Control Module 'A'.
Common causes: Common causes include Faulty Gear Shift Control Module 'A', Gear Shift Control Module 'A' harness is open or shorted, Gear Shift Control Module 'A' 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 28,943

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 Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Gear Shift Control Module 'A' has not been received.

OBDII Code U0103 - Lost Communication With Gear Shift Control Module 'A' - AutoCodes.com — U0103 Code - Lost Communication With Gear Shift Control Module 'A'

What does this mean?

What are the Possible Causes of the DTC U0103?

Faulty Gear Shift Control Module 'A'
Gear Shift Control Module 'A' harness is open or shorted
Gear Shift Control Module 'A' circuit poor electrical connection

How to Fix the DTC U0103?

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 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 U0103 code?

Need more information on how to fix the U0103 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0103 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U0103 Buick — Lost Communication With Shift Lever Module
U0103 Cadillac — Lost Communication With Shift Lever Module
U0103 Chevrolet — Lost Communication With Shift Lever Module
U0103 Chrysler — Lost Communication With Electric Gear Shift Module
U0103 Dodge — Lost Communication With Electric Gear Shift Module
U0103 GMC — Lost Communication With Shift Lever Module
U0103 Jeep — Lost Communication With Electric Gear Shift Module
U0103 RAM — Lost Communication With Electric Gear Shift Module

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 Code

1. What are the common symptoms of OBDII code U0103?

- Common symptoms include issues with shifting gears, transmission malfunctions, and dashboard warning lights related to the transmission system.

2. What are the possible causes of the U0103 code?

- The U0103 code is typically caused by a faulty gear shift control module, damaged wiring or connectors in the communication network, or a malfunctioning powertrain control module (PCM).

3. How can I diagnose the U0103 code?

- To diagnose the U0103 code, a professional diagnostic scan tool is needed to communicate with the vehicle's onboard computer system and retrieve specific error codes. Visual inspection of wiring and connectors is also recommended.

4. Can I still drive my vehicle with the U0103 code present?

- It is not recommended to drive your vehicle with the U0103 code present, as it can lead to potential transmission issues and unsafe driving conditions. It is best to have the issue diagnosed and repaired as soon as possible.

5. How can I repair the U0103 code?

- Repairing the U0103 code may involve replacing the gear shift control module, repairing damaged wiring or connectors, or resetting the PCM. It is recommended to consult a professional mechanic for an accurate diagnosis and repair.

6. Are there any DIY tips for fixing the U0103 code?

- DIY tips for fixing the U0103 code are limited, as this issue often requires specialized diagnostic equipment and knowledge. However, checking for loose connections or damaged wiring could be a good starting point.

7. Is the U0103 code a common issue in certain vehicle makes and models?

- The U0103 code can occur in various vehicle makes and models, particularly those equipped with advanced transmission control systems. It is important to address the issue promptly to avoid further damage.

8. Can extreme weather conditions cause the U0103 code to trigger?

- Extreme weather conditions, such as extreme cold or heat, can potentially affect the gear shift control module or communication network, leading to the U0103 code. Proper maintenance and care can help prevent weather-related issues.

9. Will resetting the U0103 code make it go away permanently?

- Simply resetting the U0103 code may temporarily clear the error, but if the underlying issue is not addressed, the code is likely to reappear. It is crucial to diagnose and repair the root cause of the problem.

10. How much does it typically cost to repair the U0103 code?

- The cost of repairing the U0103 code can vary depending on the specific cause of the issue, labor costs, and parts needed for the repair. It is advisable to consult a professional mechanic for an accurate cost estimate.