AutoCodes – RAM – U1140 RAM

U1140 RAM Code - Lost Communication With Active Exhaust Valve 2

Quick Answer

The purpose of the Active Exhaust Valves is to reduce exhaust noise in order to comply with pass-by noise regulations. Common causes include Faulty Active Exhaust Valve Actuator, Active Exhaust Valve Actuator harness is open or shorted, Active Exhaust Valve Actuator 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: U1140 RAM indicates Lost Communication With Active Exhaust Valve 2.
Common causes: Common causes include Faulty Active Exhaust Valve Actuator, Active Exhaust Valve Actuator harness is open or shorted, Active Exhaust Valve Actuator 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 729

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 Jul 02, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1140 RAM Description

The purpose of the Active Exhaust Valves is to reduce exhaust noise in order to comply with pass-by noise regulations. The Active Exhaust Valves system consists of two main components. The first is the mechanical butterfly valves, which are welded into the exhaust pipe on each bank. Attached to each valve is a smart actuator. These are connected to the mechanical valves via a transmission spring to help reduce heat transfer from the butterfly valves to the actuators.
The Active Exhaust Valve actuators communicate with the Powertrain Control Module (PCM) over a LIN Bus circuit. Each Active Exhaust Valve actuator, one for the left (actuator 1) and one for the right (actuator 2), has a unique part number/internal ID. The PCM can identify each actuator's location by this unique ID. Based on engine torque, rpm, and vehicle speed, the PCM sends position commands to the Active Exhaust Valve actuators. These actuators then move the butterfly valves to the commanded positions. An internal Hall Effect sensor counts the pulses to determine the valve position. The valve actuators are calibrated at every Key-ON event; the PCM sends full open and full closed commands and checks the actual position against the commanded position. If calibration is unsuccessful for any reason, the actuators self-diagnose and report fault flags to the PCM over the LIN Bus.
If the valve position does not match the predetermined calibration, a performance code is set, and the valves will default to the full open position. If an actuator is not attached to the mechanical valve, or if the transmission spring is broken or missing, the actuator will continue to rotate indefinitely and set a fault. Additionally, if the mechanical valve is stuck and cannot move, a fault will be set.

OBDII Code U1140 RAM - Lost Communication With Active Exhaust Valve 2 - AutoCodes.com — U1140 RAM Code - Lost Communication With Active Exhaust Valve 2

What does this mean?

What are the Possible Causes of the DTC U1140 RAM?

Faulty Active Exhaust Valve Actuator
Active Exhaust Valve Actuator harness is open or shorted
Active Exhaust Valve Actuator circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC U1140 RAM?

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 U1140 RAM 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 U1140 RAM Code

1. What are the common symptoms of OBDII code U1140 RAM Lost Communication With Active Exhaust Valve 2?

- Common symptoms include illuminated check engine light, poor engine performance, and issues with the exhaust system.

2. What are the possible causes of code U1140 RAM Lost Communication With Active Exhaust Valve 2?

- Possible causes may include a faulty active exhaust valve, damaged wiring or connectors, issues with the exhaust valve control module, or a communication error within the vehicle's network.

3. How can I diagnose OBDII code U1140 RAM Lost Communication With Active Exhaust Valve 2?

- Diagnosis typically involves using a diagnostic scanner to retrieve the specific fault code, checking the wiring and connectors related to the active exhaust valve, and testing the exhaust valve control module for proper functionality.

4. Can I continue driving my vehicle with OBDII code U1140 RAM present?

- It is not recommended to drive with a persistent U1140 RAM code, as it can lead to further damage to the exhaust system and affect the overall performance of the vehicle.

5. How can I repair OBDII code U1140 RAM Lost Communication With Active Exhaust Valve 2?

- Repair options may include replacing the faulty active exhaust valve, repairing or replacing damaged wiring or connectors, resetting the exhaust valve control module, or addressing any communication network issues within the vehicle.

6. Will resetting the fault codes make OBDII code U1140 RAM disappear permanently?

- Resetting the fault codes may temporarily clear the code, but if the underlying issue causing the U1140 RAM code is not addressed, it is likely to reappear once the problem resurfaces.

7. Is it possible to fix OBDII code U1140 RAM Lost Communication With Active Exhaust Valve 2 without professional help?

- While some basic troubleshooting steps can be performed by DIY enthusiasts, diagnosing and repairing complex issues related to this code may require professional assistance to ensure proper and effective resolution.

8. Can a disconnected or malfunctioning active exhaust valve cause code U1140 RAM to appear?

- Yes, a disconnected or malfunctioning active exhaust valve can trigger the U1140 RAM code due to the loss of communication or signal with the vehicle's control systems.

9. Are there any specific vehicle models known to be prone to experiencing OBDII code U1140 RAM Lost Communication With Active Exhaust Valve 2?

- While the U1140 RAM code can occur in various vehicle models equipped with active exhaust systems, some specific makes and models may have a higher incidence of this issue due to design or manufacturing factors.

10. How can regular maintenance help prevent OBDII code U1140 RAM from occurring?

- Regular maintenance, such as checking and cleaning the active exhaust valve components, inspecting wiring harnesses for damage, and ensuring proper system operation, can help prevent issues that may trigger the U1140 RAM code.