AutoCodes – Generic – U011C

U011C Code - Lost Communication With Rocker Arm Control Module 'B'

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Rocker Arm Control Module 'B', Rocker Arm Control Module 'B' harness is open or shorted, Rocker Arm 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: U011C indicates Lost Communication With Rocker Arm Control Module 'B'.
Common causes: Common causes include Faulty Rocker Arm Control Module 'B', Rocker Arm Control Module 'B' harness is open or shorted, Rocker Arm 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 2,314

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 Mar 30, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code U011C Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Rocker Arm Control Module 'B' has not been received.

OBDII Code U011C - Lost Communication With Rocker Arm Control Module 'B' - AutoCodes.com — U011C Code - Lost Communication With Rocker Arm Control Module 'B'

What does this mean?

What are the Possible Causes of the DTC U011C?

Faulty Rocker Arm Control Module 'B'
Rocker Arm Control Module 'B' harness is open or shorted
Rocker Arm Control Module 'B' circuit poor electrical connection

How to Fix the DTC U011C?

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 U011C 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.