What Does C1287 Mean?
The brake booster pedal force switch circuit has failed. This switch detects when the driver is applying significant braking force (hard braking), allowing the stability control system to activate enhanced features like Brake Assist or Emergency Brake Amplification. With this circuit failed, the system cannot detect panic braking situations and these assist features are disabled.
Common Causes
35%
Faulty brake booster pedal force switch (internal open or stuck contact)
25%
Wiring open or short in the pedal force switch circuit
20%
Corroded or disconnected connector at the brake booster or switch
15%
Brake booster mechanical failure preventing proper switch actuation
5%
EBCM input circuit fault for the pedal force switch signal
Diagnostic Steps
1
Monitor the brake pedal force switch PID in live data — press the brake pedal firmly (panic-stop force) and verify the switch state toggles from OFF to ON. If it never changes, the switch or circuit is faulty.
2
Locate the pedal force switch on the brake booster (usually on the front of the booster or integrated into the pushrod) and test it directly with a multimeter — it should show continuity when firmly pressed and open when released.
3
Inspect the switch connector and wiring from the switch through the firewall to the EBCM for damage, corrosion, or broken wires. The firewall pass-through area is a common failure point due to vibration and moisture.
4
Verify the brake booster is functioning correctly — with the engine off, pump the brake pedal several times to deplete vacuum, then hold the pedal and start the engine. The pedal should drop slightly, confirming booster assist. A failed booster may not actuate the force switch properly.
5
If the switch and wiring are good, check for voltage at the EBCM connector on the force switch input pin while pressing the brake hard — if voltage is present but the code remains, the EBCM input may be faulty.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
The brake booster pedal force switch circuit has failed. This switch detects when the driver is applying significant braking force (hard braking), allowing the stability control system to activate enhanced features like Brake Assist or Emergency Brake Amplification. With this circuit failed, the sys...
The most common cause of C1287 (Booster Pedal Force switch circuit Failure) is: Faulty brake booster pedal force switch (internal open or stuck contact)
Typical repair costs for C1287 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Standard braking still functions normally, but the Brake Assist or Emergency Brake Amplification feature is disabled. In a panic stop, the system will not provide additional braking force beyond what the driver applies. This mainly affects emergency situations. The vehicle is safe for normal driving, but maximum braking performance in emergencies may be reduced. Repair at your earliest convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1287 to identify the root cause.
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Quick Info
Category
Chassis
System
Brake Assist / Stability Control
Difficulty
Type
Manufacturer
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