U011B — Lost Communication With Rocker Arm Control Module A

What Does U011B Mean?

U011B is a diagnostic trouble code indicating: Lost Communication With Rocker Arm Control Module A. This code relates to the network communication system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of U011B

⚠️ Check Engine Light (MIL) illuminated
⚠️ No communication with Rocker Arm Control Module A
⚠️ Multiple warning lights may illuminate simultaneously
⚠️ Related system completely inoperative
⚠️ Multiple warning lights on dashboard

Common Causes

🔍 CAN bus wiring fault (open or shorted) to Rocker Arm Control Module A
🔍 Power or ground supply issue to Rocker Arm Control Module A
🔍 Rocker Arm Control Module A internal failure
🔍 Water intrusion damaging module or connectors
🔍 CAN bus termination resistor fault

Frequently Asked Questions

What does U011B mean?

U011B indicates: Lost Communication With Rocker Arm Control Module A. The vehicle's computer has detected that the Rocker Arm Control Module A is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code U011B?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with U011B for extended periods may cause additional problems.

How much does it cost to fix U011B?

Repair costs for U011B typically range from $80 to $1200, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Inspect CAN bus wiring to Rocker Arm Control Module A for damage
🔧 Check power and ground supply to Rocker Arm Control Module A
🔧 Replace failed Rocker Arm Control Module A

1
Find your vehicle above
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

U011B: Lost Communication With Rocker Arm Control Module A