AutoCodes – Generic – U1439

U1439 Code - Implausible/Missing Programmed Axle Ratio

Quick Answer

The Diagnostic Trouble Code (DTC) sets when the Body Control Module (BCM) reports via Controller Area Network (CAN) message that the axle ratio signal is not available. Common causes include Faulty Body Control Module (BCM), Body Control Module harness is open or shorted, Body 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: U1439 indicates Implausible/Missing Programmed Axle Ratio.
Common causes: Common causes include Faulty Body Control Module (BCM), Body Control Module harness is open or shorted, Body 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 1,231

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 May 23, 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 U1439 Description

The Diagnostic Trouble Code (DTC) sets when the Body Control Module (BCM) reports via Controller Area Network (CAN) message that the axle ratio signal is not available.

OBDII Code U1439 - Implausible/Missing Programmed Axle Ratio - AutoCodes.com — U1439 Code - Implausible/Missing Programmed Axle Ratio

What does this mean?

What are the Possible Causes of the DTC U1439?

Faulty Body Control Module (BCM)
Body Control Module harness is open or shorted
Body Control Module circuit poor electrical connection

How to Fix the DTC U1439?

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 U1439 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 U1439 code?

Need more information on how to fix the U1439 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1439 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1439 Chrysler — Implausible/Missing Programmed Axle Ratio
U1439 Dodge — Implausible/Missing Programmed Axle Ratio
U1439 Jeep — Implausible/Missing Programmed Axle Ratio
U1439 RAM — Implausible/Missing Programmed Axle Ratio

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 U1439 Code

1. What does OBDII code U1439 mean?

This code indicates an implausible or missing programmed axle ratio in the vehicle's computer system.

2. What are the common symptoms of OBDII code U1439?

Common symptoms include erratic shifting, decreased fuel efficiency, and potential issues with the vehicle's traction control system.

3. What are the possible causes of OBDII code U1439?

Causes may include a faulty wheel speed sensor, a malfunctioning ABS module, incorrect tire size, or a software glitch in the vehicle's computer system.

4. How is OBDII code U1439 diagnosed?

Diagnosis typically involves using an OBDII scanner to retrieve the code, checking for any related codes or issues, and conducting a visual inspection of the wheel speed sensors and ABS components.

5. How can OBDII code U1439 be repaired?

Repair may involve reprogramming the axle ratio in the vehicle's computer system, replacing a faulty wheel speed sensor, recalibrating the ABS module, or correcting the tire size settings.

6. Is it safe to continue driving with OBDII code U1439 present?

It is generally not recommended to drive with this code active, as it can affect the vehicle's performance and safety systems. It is best to address the issue promptly.

7. Can OBDII code U1439 be reset without fixing the underlying issue?

While the code can be cleared temporarily, it is likely to reappear if the root cause is not addressed. It is important to diagnose and repair the issue to prevent further problems.

8. Does OBDII code U1439 affect emissions or engine performance?

While this code may not directly impact emissions or engine performance, it can lead to other issues like improper shifting and reduced fuel efficiency if left unresolved.

9. Can a DIY enthusiast fix OBDII code U1439 at home?

Depending on the underlying cause, some repairs related to this code may be possible for DIY enthusiasts with the necessary tools and knowledge. However, complex issues may require professional assistance.

10. Is OBDII code U1439 a common issue in certain vehicle makes or models?

This code may be more prevalent in vehicles with traction control systems or ABS modules prone to failure, but it can potentially occur in any vehicle with the specified symptoms.