What Does B1486 Mean?
This code indicates the Body Control Module (BCM) has detected an abnormal short-to-ground condition in the brake pedal position switch input circuit. The brake pedal input signal is used for multiple safety systems including cruise control, transmission shift interlock, engine start permissive, and brake light activation. The BCM has identified that the circuit voltage is being pulled to ground when it should not be, preventing proper brake pedal position monitoring.
Common Causes
40%
Damaged or chafed wiring harness causing short to ground between brake pedal switch and BCM
30%
Faulty brake pedal position switch with internal short to ground
20%
Corroded or water-damaged connector terminals at brake pedal switch causing ground short
10%
BCM internal circuit failure or moisture intrusion causing false ground detection
Diagnostic Steps
1
Step 1: Perform visual inspection of brake pedal switch and wiring harness from pedal assembly through firewall to BCM, looking for damaged insulation, pinched wires, corrosion, or signs of water intrusion. Check connector terminals for pushed-back pins or corrosion.
2
Step 2: Disconnect brake pedal switch connector and measure resistance between the signal circuit terminal (consult wiring diagram for specific pin) and chassis ground with a digital multimeter. Reading should be greater than 10,000 ohms; low resistance indicates wiring harness short to ground.
3
Step 3: With switch still disconnected, measure resistance of the brake pedal switch itself between signal terminal and ground terminal. Compare readings to manufacturer specifications in both pressed and released positions. Infinite resistance to ground on signal circuit indicates switch is likely faulty if wiring tested good.
4
Step 4: If wiring and switch test within specifications, inspect BCM connector for corrosion or moisture, and perform voltage drop test on ground circuits. Measure reference voltage at BCM connector brake pedal input pin with switch connected and pedal released (should read battery voltage or 5V depending on system design).
5
Step 5: Repair or replace identified faulty component (wiring, connector, or switch), clear codes, and verify brake pedal input signal displays correctly on scan tool in both pressed and released positions. Test all related systems including brake lights, cruise control, and shift interlock for proper operation.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an abnormal short-to-ground condition in the brake pedal position switch input circuit. The brake pedal input signal is used for multiple safety systems including cruise control, transmission shift interlock, engine start permissive, and...
The most common cause of B1486 (Brake Pedal Input Circuit Ground Short) is: Damaged or chafed wiring harness causing short to ground between brake pedal switch and BCM
Typical repair costs for B1486 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is generally safe to drive, but cruise control may not function or disengage properly, transmission may not shift out of park, and brake lights may not operate correctly, creating a rear-end collision hazard. Repair should be completed promptly to restore all safety systems.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1486 to identify the root cause.
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Quick Info
Category
Body
System
Brake System / Body Control Module
Difficulty
Type
Manufacturer
Recommended Tools
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