AutoCodes – Generic – U1839

U1839 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 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.

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Code Popularity 757

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

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?

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 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 code?

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

Need Help with the Code?

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

Information for Specific Makes

U1839 Buick — Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control Module
U1839 Cadillac — Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control Module
U1839 Chevrolet — Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control Module
U1839 GMC — Auxiliary Transmission Fluid Pump Control Module Lost Communication With Engine Control 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 U1839 Code

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

- Common symptoms include rough shifting, transmission slipping, poor fuel efficiency, and illuminated warning lights on the dashboard.

2. What can cause the OBDII code U1839 to trigger?

- The code U1839 is usually triggered when there is a communication failure between the auxiliary transmission fluid pump control module and the engine control module.

3. How serious is the OBDII code U1839?

- The code U1839 should be addressed promptly as it can lead to transmission issues and affect the overall performance of the vehicle.

4. How can I diagnose the OBDII code U1839?

- Diagnosing the code U1839 typically involves using an OBDII scanner to retrieve the code, checking for any other related codes, and inspecting the wiring and connections between the modules.

5. What are some repair tips for OBDII code U1839?

- Repair tips include checking and repairing any damaged wiring or connections, resetting the fault codes after repairs, and testing the communication between the modules.

6. Can I drive my vehicle with the OBDII code U1839?

- It is not recommended to drive the vehicle with the code U1839 as it can lead to further transmission problems and potential safety hazards.

7. How much does it cost to repair the OBDII code U1839?

- The cost of repairing the code U1839 can vary depending on the extent of the issue, but it may involve replacing faulty modules, repairing wiring, or updating software.

8. Can I reset the OBDII code U1839 without fixing the issue?

- While you can clear the code temporarily, it is important to address the underlying cause to prevent further damage to the vehicle's transmission system.

9. Are there any preventive measures to avoid OBDII code U1839?

- Regular vehicle maintenance, including checking for any wiring issues or module communication problems, can help prevent the occurrence of the code U1839.

10. How long does it take to repair OBDII code U1839?

- The repair time for the code U1839 can vary depending on the complexity of the issue, but it may take a few hours to a day to diagnose and fix the problem.