What Does U0014 Mean?
The CAN High wire on the medium-speed network is reading abnormally high voltage, suggesting a short to power or voltage source. The positive differential signal cannot return to proper recessive state voltage.
Common Causes
35%
CAN High wire shorted to 12V power source due to damaged harness or pinched wire contacting power circuit
30%
Faulty module with internal short connecting CAN High to power supply internally
20%
Damaged or incorrectly installed connector causing cross-connection between power and CAN High pins
10%
Aftermarket accessory improperly wired into vehicle network, applying voltage to CAN High circuit
5%
Failed biasing circuit in gateway or module applying excessive voltage to CAN High line
Diagnostic Steps
1
Step 1: Measure voltage on CAN High wire at multiple accessible points with key on (normal is ~2.5-3.5V, reading near 12V confirms short to power)
2
Step 2: Disconnect modules from medium-speed network one at a time while monitoring voltage to isolate source of high voltage condition
3
Step 3: Inspect all wiring harnesses for damage, particularly near fuse boxes, power distribution centers, and areas where harness may contact hot or powered components
4
Step 4: Check for recent repairs, modifications, or aftermarket installations that may have compromised wire insulation or created unintended connections
5
Step 5: With suspected module disconnected, inspect connector for bent pins, corrosion, or evidence of overheating that could indicate internal module fault
Estimated Repair Cost
$150 - $1,600
Parts + labor, varies by vehicle and location
The CAN High wire on the medium-speed network is reading abnormally high voltage, suggesting a short to power or voltage source. The positive differential signal cannot return to proper recessive state voltage.
The most common cause of U0014 (Medium Speed CAN Communication Bus (+) High) is: CAN High wire shorted to 12V power source due to damaged harness or pinched wire contacting power circuit
Typical repair costs for U0014 range from $150 to $1,600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Medium-speed network failure affects comfort and convenience systems primarily. Vehicle remains drivable but may have multiple inoperative features and warning lights illuminated. Prolonged short to power could damage modules.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0014 to identify the root cause.
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Quick Info
Category
Network
System
Network Communications
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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