What Does C0286 Mean?
This code indicates the ABS control module has detected that the ABS warning lamp circuit is shorted to battery positive voltage (B+). Instead of the module controlling the lamp through a ground or switched power circuit, the lamp circuit is receiving constant battery voltage from an unintended source. This prevents the ABS module from properly controlling the warning lamp and indicates a wiring or lamp circuit fault.
Common Causes
45%
Damaged or chafed wiring harness causing short to power in the ABS lamp circuit between instrument cluster and ABS module
30%
Failed instrument cluster circuit board with internal short to power on ABS lamp driver circuit
15%
Incorrect wiring repair or aftermarket accessory installation causing cross-circuit short to B+
10%
Faulty ABS control module with internal short detection error or damaged lamp driver output
Diagnostic Steps
1
Step 1: Perform visual inspection of instrument cluster wiring harness and ABS module harness for obvious damage, chafing against metal edges, pinch points, or signs of previous repairs near the firewall and under dash areas
2
Step 2: Disconnect instrument cluster connector and measure voltage on the ABS lamp circuit wire with ignition ON using a digital multimeter - should read 0 volts if shorted externally, or battery voltage if short exists in harness
3
Step 3: With cluster disconnected and ignition ON, check for continuity between the ABS lamp circuit wire and any known B+ power sources in the dash harness using multimeter in ohms mode - less than 5 ohms indicates direct short
4
Step 4: If no external short found, reconnect cluster and backprobe the ABS lamp circuit at the ABS control module connector with ignition ON - battery voltage present here confirms cluster internal fault
5
Step 5: Repair identified shorted wiring or replace faulty component, clear codes, cycle ignition multiple times and verify ABS lamp operates normally during bulb check and extinguishes after startup
6
Step 6: Road test vehicle and verify ABS lamp does not illuminate, monitor for code return using scan tool live data during normal ABS system operation
Estimated Repair Cost
$100 - $650
Parts + labor, varies by vehicle and location
This code indicates the ABS control module has detected that the ABS warning lamp circuit is shorted to battery positive voltage (B+). Instead of the module controlling the lamp through a ground or switched power circuit, the lamp circuit is receiving constant battery voltage from an unintended sour...
The most common cause of C0286 (ABS Indicator Lamp Circuit Shorted to B+) is: Damaged or chafed wiring harness causing short to power in the ABS lamp circuit between instrument cluster and ABS module
Typical repair costs for C0286 range from $100 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is generally safe to drive as the ABS system may still function, but the warning lamp circuit fault prevents proper notification of actual ABS system failures. Repair promptly to ensure you will be alerted to any future ABS malfunctions that could affect emergency braking performance.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C0286 to identify the root cause.
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Quick Info
Category
Chassis
System
Anti-lock Braking System (ABS) Warning Lamp Circuit
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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