What Does U0048 Mean?
The positive wire of communication bus C has an open circuit or break. This prevents proper differential signaling and disrupts network communication.
Common Causes
40%
Broken or severed CAN C(+) wire in harness
30%
Disconnected or backed-out connector terminal on CAN C(+) circuit
15%
Corroded connector causing complete loss of continuity
10%
Failed control module with open internal bus connection
5%
Harness damage at flex points or routing locations
Diagnostic Steps
1
Step 1: Check continuity of CAN C(+) wire from end to end using wiring diagram
2
Step 2: Inspect all connectors on bus C circuit; ensure terminals are fully seated and locked
3
Step 3: Wiggle test harness while monitoring bus voltage to identify intermittent breaks
4
Step 4: Check for damaged wiring at common failure points: door hinges, under seats, behind panels
5
Step 5: Repair open circuit by replacing damaged wire section or repairing connector
Estimated Repair Cost
$150 - $1,000
Parts + labor, varies by vehicle and location
The positive wire of communication bus C has an open circuit or break. This prevents proper differential signaling and disrupts network communication.
The most common cause of U0048 (Vehicle Communication Bus C (+) Open) is: Broken or severed CAN C(+) wire in harness
Typical repair costs for U0048 range from $150 to $1,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of bus C communication can disable multiple vehicle systems. Severity depends on which systems communicate on this bus, but may affect critical safety or operational functions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0048 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.
