AutoCodes – Jeep – U0291 Jeep

U0291 Jeep Code - Lost Communication With Gear Shift Control Module 'B'

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to connect automotive devices without a host computer. Common causes include Faulty Gear Shift Control Module 'B', Gear Shift Control Module 'B' harness is open or shorted, Gear Shift Control Module 'B' 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: U0291 Jeep indicates Lost Communication With Gear Shift Control Module 'B'.
Common causes: Common causes include Faulty Gear Shift Control Module 'B', Gear Shift Control Module 'B' harness is open or shorted, Gear Shift Control Module 'B' 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 104

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 Aug 26, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0291 Jeep Description

A Controller Area Network (CAN) is a vehicle bus standard designed to connect automotive devices without a host computer. Operating information and commands are exchanged among the devices, which are programmed to know which messages need to be exchanged over the serial data circuits. The CAN bus uses two dedicated wires for communication, known as CAN high and CAN low. In idle mode, both lines carry 2.5V. During data transmission, the CAN high line rises to 3.75V and the CAN low drops to 1.25V, creating a 2.5V differential between the lines. Since communication depends on this voltage differential, the CAN bus is not sensitive to inductive spikes, electrical fields, or other forms of noise. A Diagnostic Trouble Code (DTC) is set when a periodic message from the Gear Shift Control Module 'B' is not received.

OBDII Code U0291 Jeep - Lost Communication With Gear Shift Control Module 'B' - AutoCodes.com — U0291 Jeep Code - Lost Communication With Gear Shift Control Module 'B'

What does this mean?

What are the Possible Causes of the DTC U0291 Jeep?

Faulty Gear Shift Control Module 'B'
Gear Shift Control Module 'B' harness is open or shorted
Gear Shift Control Module 'B' circuit poor electrical connection

How to Fix the DTC U0291 Jeep?

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 U0291 Jeep 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.

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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 U0291 Jeep Code

What does the OBDII code U0291 mean on a Jeep?

The code U0291 indicates that the vehicle's systems have lost communication with the Gear Shift Control Module 'B'.

What are common symptoms of the U0291 code on a Jeep?

Symptoms may include the inability to shift gears, transmission-related warnings on the dashboard, or a vehicle stuck in limp mode.

What causes the U0291 code on a Jeep?

The code can be caused by faulty wiring, a failed Gear Shift Control Module, network communication issues, or a malfunctioning Transmission Control Module.

Can I still drive my Jeep with the U0291 code?

Driving with the U0291 code is not recommended as it may lead to limited gear functionality or further transmission damage.

How do I diagnose the U0291 code on a Jeep?

Diagnose the code by inspecting the wiring and connectors to the Gear Shift Control Module, checking for corrosion, and scanning for related codes using an OBDII scanner.

What should I check first when troubleshooting the U0291 code on a Jeep?

Start by checking the wiring and connectors for damage or loose connections near the Gear Shift Control Module and Transmission Control Module.

Can a software issue cause the U0291 code on a Jeep?

Yes, outdated or corrupted software in the Transmission Control Module or related systems can sometimes trigger the U0291 code.

How much does it cost to repair the U0291 code on a Jeep?

Repair costs vary but may include diagnostics ($100-$200), wiring repairs ($50-$300), or Gear Shift Control Module replacement ($400-$800).

Is the Gear Shift Control Module the only component responsible for the U0291 code?

No, while the Gear Shift Control Module is the primary component, issues with wiring, connectors, or other communication modules can also cause the code.

Can clearing the U0291 code solve the problem on a Jeep?

Clearing the code may temporarily remove the error, but the underlying issue must be repaired to prevent the code from returning.