What Does U0071 Mean?
The negative wire of communication bus E is reading a voltage higher than expected. This indicates a short to power or ground reference problem on the network's negative circuit.
Common Causes
35%
CAN bus E negative wire shorted to power or voltage source
30%
Damaged or corroded connector terminals on bus E circuit
20%
Failed module creating voltage feedback on bus E negative line
15%
Pinched or chafed wiring harness causing intermittent short
Diagnostic Steps
1
Step 1: Visually inspect all connectors on communication bus E for corrosion, damage, or loose connections
2
Step 2: Use a digital multimeter to measure voltage on bus E negative wire with ignition on, should read near ground (0V)
3
Step 3: Check for continuity between bus E negative wire and any power sources using wiring diagram
4
Step 4: Disconnect modules one at a time to isolate which module may be creating the high voltage condition
5
Step 5: Inspect wiring harness routing for pinch points, chafing against chassis, or heat damage
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The negative wire of communication bus E is reading a voltage higher than expected. This indicates a short to power or ground reference problem on the network's negative circuit.
The most common cause of U0071 (Vehicle Communication Bus E (-) High) is: CAN bus E negative wire shorted to power or voltage source
Typical repair costs for U0071 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May cause multiple system warnings and loss of advanced safety features. Vehicle may enter limp mode or experience drivability issues.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0071 to identify the root cause.
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Quick Info
Category
Network
System
Network Communication
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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