Engine-CodesGeneric – U1839

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

Quick Answer

The U1839 diagnostic trouble code (DTC) indicates that the auxiliary transmission fluid pump control module has lost communication with the engine control module in a vehicle. Common causes include Faulty auxiliary transmission fluid pump control module, Loose or corroded wiring connections between modules, Software or firmware issues in the control modules. 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 auxiliary transmission fluid pump control module, Loose or corroded wiring connections between modules, Software or firmware issues in the control modules.
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.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code U1839 Description

The U1839 diagnostic trouble code (DTC) indicates that the auxiliary transmission fluid pump control module has lost communication with the engine control module in a vehicle. In modern vehicles, various modules and control units communicate with each other over a network known as the Controller Area Network (CAN). This communication network is essential for the proper functioning of the vehicle's systems and components.

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

Common Causes of U1839

  1. Faulty auxiliary transmission fluid pump control module
  2. Loose or corroded wiring connections between modules
  3. Software or firmware issues in the control modules
  4. Electrical system problems, such as a damaged CAN bus
  5. Water intrusion or physical damage to the control modules

Symptoms of U1839

  1. Erratic shifting or hesitation during gear changes
  2. Transmission slipping or jerking
  3. Reduced fuel efficiency
  4. Engine stalling or rough idling
  5. Illumination of the check engine light

How to Fix U1839

  1. Perform a comprehensive diagnostic scan to identify the exact cause of the communication failure.
  2. Inspect and test the wiring connections between the auxiliary transmission fluid pump control module and the engine control module.
  3. Check for any software updates or reprogramming required for the control modules.
  4. Replace any faulty control modules or components, such as the auxiliary transmission fluid pump control module.
  5. Clear the DTC and perform a test drive to ensure proper communication and functionality between the modules.

Cost to Fix U1839

The cost of repairing a U1839 DTC can vary depending on the specific cause of the communication failure and the labor rates in your area. On average, the repair costs for this issue can range from $200 to $500, including parts and labor. However, it is recommended to consult with a professional mechanic or dealership to get an accurate estimate based on the vehicle make and model, as well as any additional diagnostic or repair steps required. Keep in mind that labor rates can vary significantly, so it's advisable to inquire about the specific rates at local auto repair shops before proceeding with the repair.

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Code U1839 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.

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