Lost Communication With Motor Generator Control Module B
The U0211 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Motor Generator Control Module B. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $800 - $3,500 (parts and labor)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- Hybrid system warning light on
- Engine cannot start via MG2
- Loss of electric assist
- Reduced power and acceleration
- Transmission-related warnings
Probable Causes (Ranked by Likelihood)
- Failed motor generator B control module Very High
- Wiring fault in high-voltage harness High
- CAN bus communication issue Moderate
- Overheated motor generator B Low
Step-by-Step Diagnostic Procedure
-
Scan motor generator B module for codes
-
Check high-voltage wiring to MG2
-
Test CAN bus signals at MG-B connector
-
Inspect coolant system for MG2 overheating
Frequently Asked Questions
Can I drive with U0211?
No. Motor generator B starts the engine in hybrids. Without it the vehicle may not start.
What causes U0211?
Most commonly a failed MG-B control module or high-voltage wiring issue.
Is U0211 the same as U0210?
No. They refer to different motor generators serving different functions.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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