U011B
Lost Communication With Rocker Arm Control Module A
ECU lost CAN communication with rocker arm control module A (variable valve actuation). A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
ECU lost CAN communication with rocker arm control module A (variable valve actuation). A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
Common causes
- high
Module unpowered
One of the most commonly reported causes for this code — check this first.
Typical part cost: $110-1320
- low
Gateway module routing CAN messages incorrectly
Less common, but worth ruling out after the more likely causes.
Typical part cost: $110-1320
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does U011B mean?
U011B means "Lost Communication With Rocker Arm Control Module A". It is a generic OBD-II code that points to a fault in the network / communication.
What are the most common causes of U011B?
module unpowered; gateway module routing can messages incorrectly; can terminating resistor (120 ω) drifted out of spec — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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