What Does U0026 Mean?
The negative (-) line of the low-speed CAN bus voltage is reading higher than specification. This typically indicates a short to voltage or an issue with the CAN+ circuit affecting CAN- voltage.
Common Causes
35%
CAN- wire shorted to battery voltage or ignition power
25%
Failed module with internal short to power on CAN- circuit
20%
Damaged connector with cross-contamination between circuits
10%
Improper repair with CAN- connected to wrong circuit
10%
Short circuit from aftermarket installation or accessory wiring
Diagnostic Steps
1
Step 1: Measure voltage on CAN- line with key on; voltage above 3.0V indicates high condition
2
Step 2: Disconnect modules individually and monitor CAN- voltage to isolate faulty module
3
Step 3: Check for voltage present on CAN- circuit with all modules disconnected (should be 0V)
4
Step 4: Inspect connectors for evidence of pin-to-pin shorts, melted terminals, or crossed wires
5
Step 5: Review recent repairs or aftermarket installations that may have compromised CAN wiring integrity
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
The negative (-) line of the low-speed CAN bus voltage is reading higher than specification. This typically indicates a short to voltage or an issue with the CAN+ circuit affecting CAN- voltage.
The most common cause of U0026 (Low Speed CAN Communication Bus (-) High) is: CAN- wire shorted to battery voltage or ignition power
Typical repair costs for U0026 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Elevated voltage on CAN- may damage modules and cause network failure. Multiple systems may malfunction, potentially affecting vehicle safety features.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0026 to identify the root cause.
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Quick Info
Category
Network
System
Network Communications
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
