AutoCodes – GMC – U1839 GMC

U1839 GMC Code - Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control Module

Quick Answer

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine Control 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: U1839 GMC indicates Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control Module.
Common causes: Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine Control 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 626

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 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code U1839 GMC Description

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Once the scan tool is connected to the serial data circuit through the Data Link Connector (DLC), the scan tool can be used to monitor each device for diagnostic purposes and to check for Diagnostic Trouble Code (DTC). When the vehicle is ON, each device communicating on the serial data circuit sends a state of health message to ensure that the device is operating properly. When a device stops communicating on the serial data circuit, for example, if the device loses power or ground, the state of health message it normally sends on the serial data circuit disappears. Other devices on the serial data circuit, which expect to receive that state of the health message, detect its absence; those devices in turn set a DTC associated with the loss of the state of health of the non-communicating device. A loss of serial data communications DTC does not represent a failure of the devices that contain the stored DTC. The DTC will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U1839 GMC - Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control Module - AutoCodes.com — U1839 GMC Code - Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control Module

What does this mean?

What are the Possible Causes of the DTC U1839 GMC?

Faulty Engine Control Module (ECM)
Engine Control Module harness is open or shorted
Engine Control Module circuit poor electrical connection

How to Fix the DTC U1839 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 U1839 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 U1839 GMC code?

Need more information on how to fix the U1839 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1839 GMC code diagnosed by a professional: Find a repair shop in your area

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 U1839 GMC Code

1. What are common symptoms of OBDII code U1839 GMC?

- Common symptoms include transmission shifting issues, illuminated warning lights on the dashboard, and possible vehicle stalling or loss of power.

2. What can cause the U1839 GMC code to appear?

- The code can be triggered by a communication problem between the auxiliary transmission fluid pump control module and the engine control module, often due to wiring issues, faulty modules, or poor connections.

3. How can I diagnose the U1839 code?

- Diagnosis typically involves using a diagnostic scanner to retrieve the code, checking for any related codes, inspecting the wiring and connectors between modules, and testing the modules themselves for faults.

4. Can I still drive my vehicle with the U1839 code present?

- It is not recommended to drive your vehicle with the U1839 code active, as it can lead to potential transmission issues and further damage if left unresolved.

5. What are the repair options for U1839 GMC code?

- Repair options may include repairing or replacing damaged wiring, ensuring proper connections between modules, and replacing faulty control modules as needed.

6. How much does it cost to fix the U1839 code?

- The cost of fixing the U1839 code can vary depending on the extent of the issue, the specific repairs needed, and whether any parts require replacement. It is advisable to consult with a professional mechanic for an accurate estimate.

7. Can I reset the U1839 code without fixing the underlying issue?

- While you can clear the code using a diagnostic scanner, it is important to address the root cause of the problem to prevent it from reoccurring and potentially causing further damage to your vehicle.

8. Are there any preventive maintenance tips to avoid the U1839 code?

- Regular vehicle maintenance, including checking and maintaining proper wiring connections, can help prevent issues that may lead to the U1839 code.

9. Is the U1839 code specific to GMC vehicles only?

- The U1839 code is specific to GMC vehicles, indicating a communication issue between the auxiliary transmission fluid pump control module and the engine control module in GMC vehicles.

10. Can a DIY enthusiast resolve the U1839 code on their own?

- While some DIY enthusiasts may have the skills to diagnose and repair issues related to the U1839 code, it is recommended to seek professional help, especially when dealing with complex electrical systems in modern vehicles.