What Does U0046 Mean?
A general fault has been detected on communication bus C. This indicates the network is not functioning properly but does not specify the exact nature of the problem.
Common Causes
30%
Damaged or disconnected wiring on bus C circuit
25%
Faulty control module on bus C network
20%
Intermittent connection or corrosion in bus C connectors
15%
Missing or incorrect terminating resistor on bus C
10%
Low battery voltage affecting bus communication
Diagnostic Steps
1
Step 1: Check for additional U-codes that provide more specific information about bus C fault
2
Step 2: Measure voltage on both CAN C(+) and C(-) lines; should read approximately 2.5V each with bus idle
3
Step 3: Verify terminating resistor is present; measure 60 ohms between CAN C(+) and C(-) with modules connected
4
Step 4: Inspect all bus C connectors and wiring for damage, corrosion, or poor connections
5
Step 5: Monitor live data for module communication status to identify which modules are not responding
Estimated Repair Cost
$150 - $1,500
Parts + labor, varies by vehicle and location
A general fault has been detected on communication bus C. This indicates the network is not functioning properly but does not specify the exact nature of the problem.
The most common cause of U0046 (Vehicle Communication Bus C) is: Damaged or disconnected wiring on bus C circuit
Typical repair costs for U0046 range from $150 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Depending on which systems use bus C, may affect vehicle operation, safety systems, or comfort features. Some vehicles may enter limp mode or experience reduced functionality.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0046 to identify the root cause.
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Quick Info
Category
Network
System
Vehicle Communication Network
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
