What Does B1485 Mean?
This code indicates that the Body Control Module (BCM) has detected an abnormal voltage condition in the brake pedal input circuit, specifically a short to battery voltage (12V+). The brake pedal position sensor or switch circuit is reading constant battery voltage when it should show a varying or ground-referenced signal. This fault prevents the BCM from accurately monitoring brake pedal application, which affects multiple safety and operational systems including cruise control, brake lights, shift interlock, and stability control systems.
Safety Warning
Vehicle should not be driven until repaired as brake lights may not function properly, cruise control may not disengage when braking, and transmission shift interlock may malfunction preventing gear changes. This creates significant rear-end collision risk and operational safety hazards.
Common Causes
40%
Damaged or chafed wiring harness causing short to power in brake pedal switch circuit
30%
Failed brake pedal position switch or sensor with internal short to voltage
20%
Corroded or damaged connector pins at brake pedal switch allowing cross-circuit contamination
10%
BCM internal circuit failure or water intrusion causing false voltage detection
Diagnostic Steps
1
Step 1: Perform visual inspection of brake pedal switch and associated wiring harness under dash. Look for chafed insulation, pinched wires near pedal assembly pivot points, or signs of water intrusion. Check connector for corrosion, pushed-out pins, or melted plastic.
2
Step 2: Disconnect brake pedal position switch connector and measure voltage on BCM side of harness connector using digital multimeter. Key on, engine off. Should read 0-0.5V with switch disconnected. If reading 12V+ with switch disconnected, wiring harness has short to power.
3
Step 3: With switch still disconnected, inspect wiring from brake pedal area through firewall to BCM location. Wiggle harness while monitoring voltage to locate intermittent short. Pay special attention to areas where harness passes through grommets or near sharp metal edges.
4
Step 4: If harness tests normal, reconnect brake pedal switch and backprobe connector pins while observing voltage with pedal released and applied. Signal should transition between 0V and 5V reference (varies by manufacturer). Constant 12V indicates failed switch.
5
Step 5: Repair or replace identified faulty component (harness or switch). Clear codes and verify brake pedal input signal operates correctly through full pedal travel using live data on scan tool.
6
Step 6: Test all related systems including brake lights, cruise control engagement/disengagement, shift interlock operation, and verify no codes return after test drive with multiple brake applications.
Estimated Repair Cost
$120 - $450
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected an abnormal voltage condition in the brake pedal input circuit, specifically a short to battery voltage (12V+). The brake pedal position sensor or switch circuit is reading constant battery voltage when it should show a varying or g...
The most common cause of B1485 (Brake Pedal Input Circuit Battery Short) is: Damaged or chafed wiring harness causing short to power in brake pedal switch circuit
Typical repair costs for B1485 range from $120 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle should not be driven until repaired as brake lights may not function properly, cruise control may not disengage when braking, and transmission shift interlock may malfunction preventing gear changes. This creates significant rear-end collision risk and operational safety hazards.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1485 to identify the root cause.
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Quick Info
Category
Body
System
Brake System Input / Body Control
Difficulty
Type
Manufacturer
Recommended Tools
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