U011E: Lost Communication With Throttle Actuator B Control Module

What it means

ECU lost CAN communication with throttle actuator B control module. 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.

At a glance

• Usually lights the warning light of the system that lost communication
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

Throttle actuator B control module operates or reports the second designated throttle actuator channel or unit, where fitted, and communicates with other controllers over the vehicle network. This code sets when the engine control module stops receiving expected CAN messages from that specific module; it does not by itself prove the actuator or a network resistor is faulty.

Common causes

Most likely first.

1. Module unpowered
2. Gateway module routing CAN messages incorrectly
3. CAN terminating resistor (120 Ω) drifted out of spec

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Scan all modules and record U011E, related throttle codes, and which modules can still communicate with throttle actuator B control module.
2. Review freeze-frame data and live network or throttle status to see whether the communication loss is current, intermittent, or associated with reduced-power operation.
3. Inspect the throttle actuator B module connector and harness for loose pins, corrosion, chafing, or damage, identifying B from the vehicle wiring information.
4. Check the module's power and ground under the manufacturer's specified test conditions.
5. Test the CAN wiring and termination only at the specified test points and using the manufacturer's procedure; do not assume a particular resistance value applies to every vehicle.
6. If power, ground, and network wiring pass, investigate gateway routing and the B control module with vehicle-specific diagnostics.

Common fixes

• Reconnect or repair damaged wiring or terminals at the throttle actuator B control module.
• Repair a failed power feed or ground to the B module.
• Repair a CAN open, short, or termination fault identified by the vehicle's diagnostic procedure.
• Repair a confirmed gateway fault or replace and configure throttle actuator B control module if it is proven faulty.

Can I keep driving?

If the engine warning is on, throttle response is abnormal, or the vehicle enters reduced-power mode, avoid high-speed traffic and hard acceleration and stop if you cannot control speed reliably. A communication loss can disable throttle-related functions and may leave the vehicle unable to continue.