What Does U0041 Mean?
The positive signal wire (CAN-H) of Communication Bus B is measuring higher voltage than specification. This indicates a short to voltage, bias resistor problem, or module drive circuit failure.
Common Causes
35%
CAN-H wire shorted to power source in harness
30%
Failed module with internal short to voltage on CAN-H output
25%
Damaged connector causing CAN-H to contact voltage supply pin
10%
Incorrect terminating resistor or missing bias resistors
Diagnostic Steps
1
Step 1: Measure voltage on CAN-H line with ignition on (normal is ~2.5V idle; high fault shows sustained voltage above 4V)
2
Step 2: Check for voltage between CAN-H and battery positive with all modules disconnected
3
Step 3: Disconnect modules one at a time while monitoring CAN-H voltage to identify source of high voltage
4
Step 4: Inspect connectors for crossed pins, damaged housings, or terminals making unintended contact
5
Step 5: Trace wiring harness for areas where CAN-H could contact power wires, especially at pinch points
Estimated Repair Cost
$150 - $1,200
Parts + labor, varies by vehicle and location
The positive signal wire (CAN-H) of Communication Bus B is measuring higher voltage than specification. This indicates a short to voltage, bias resistor problem, or module drive circuit failure.
The most common cause of U0041 (Vehicle Communication Bus B (+) High) is: CAN-H wire shorted to power source in harness
Typical repair costs for U0041 range from $150 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Affects non-critical systems on Bus B. Vehicle typically remains drivable but with reduced functionality of comfort or convenience features.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0041 to identify the root cause.
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Quick Info
Category
Network
System
CAN Bus Network B Communication
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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