AutoCodes – GMC – U2146 GMC

U2146 GMC Code - Lost Communication With Shift Lever Module

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Shift Lever Module (SLM), 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: U2146 GMC indicates Lost Communication With Shift Lever Module.
Common causes: Common causes include Faulty Shift Lever Module (SLM), 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 438

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 16, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U2146 GMC Description

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices 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 device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device. A loss of serial data communications Diagnostic Trouble Code (DTC) does not represent a failure of the devices that contain the stored code. The DTC will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U2146 GMC - Lost Communication With Shift Lever Module - AutoCodes.com — U2146 GMC Code - Lost Communication With Shift Lever Module

What does this mean?

What are the Possible Causes of the DTC U2146 GMC?

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

How to Fix the DTC U2146 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 U2146 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 U2146 GMC 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 U2146 GMC Code

1. What are the common symptoms of OBDII code U2146 GMC (Lost Communication With Shift Lever Module)?

- Common symptoms include difficulty shifting gears, the gear indicator not displaying correctly, and the transmission not engaging properly.

2. What are some possible causes of OBDII code U2146 GMC?

- Possible causes include a faulty shift lever module, damaged wiring or connectors in the communication network, or a problem with the powertrain control module (PCM).

3. How can I diagnose the issue causing OBDII code U2146 GMC?

- Diagnosing the issue may involve checking the wiring and connectors related to the shift lever module, performing a scan for additional trouble codes, and testing the shift lever module itself.

4. Can I still drive my vehicle with OBDII code U2146 GMC?

- It is not recommended to drive the vehicle with this code present, as it can lead to further transmission issues and potential safety hazards.

5. How can I repair OBDII code U2146 GMC?

- Repairing this code may involve replacing the shift lever module, repairing any damaged wiring or connectors, or reprogramming the PCM to establish communication with the module.

6. Are there any DIY tips for addressing OBDII code U2146 GMC?

- DIY tips include checking for loose or damaged wiring, ensuring all connectors are securely attached, and following a step-by-step diagnostic process outlined in the vehicle's service manual.

7. How much does it typically cost to fix OBDII code U2146 GMC at a repair shop?

- The cost of fixing this code can vary depending on the specific cause of the issue, but it may range from $200 to $600 at a repair shop.

8. Can resetting the trouble codes using an OBDII scanner fix code U2146 GMC?

- Resetting the trouble codes may temporarily clear the code, but it will likely reappear if the underlying issue causing the communication loss with the shift lever module is not addressed.

9. Is OBDII code U2146 GMC a common issue in GMC vehicles?

- While not extremely common, U2146 GMC can occur in GMC vehicles, particularly in models equipped with electronic shifters and advanced communication systems.

10. How can I prevent OBDII code U2146 GMC from occurring in the future?

- Regularly checking and maintaining the transmission system, ensuring proper wiring connections, and addressing any warning signs promptly can help prevent the occurrence of this code in the future.