🚨 Diagnostic Profile
- Vehicle/Equipment Make: GENERIC
- Technical Description: Brake Pedal Position Sensor B Not Learned
This is a Chassis code monitored by the Electronic Brake Control Module (EBCM). C05C1 indicates that the second (redundant) brake pedal position sensor circuit — Sensor B — has not completed its learn/calibration routine within the EBCM or electro-hydraulic brake control module. Many modern brake-by-wire and electric brake booster systems use dual, redundant pedal position sensors (Sensor A and Sensor B) to accurately and safely determine driver brake input. The control module requires both sensors to be learned together so it can cross-check their outputs for plausibility. If Sensor B’s signal was never captured during a calibration event (such as after a battery disconnect, module replacement, or pedal assembly replacement), or if its signal is erratic/out of expected range during the learn procedure, the module will set this code. This is strictly a chassis/brake system fault — it relates to the brake pedal position sensor circuit, EBCM calibration logic, ABS/stability control plausibility checks, and electro-hydraulic brake actuation, not to any engine or powertrain control.
🚨 Repair Difficulty Tier
- Difficulty Rating: Professional Only
This repair requires a bidirectional scan tool capable of performing brake pedal sensor learn/calibration procedures specific to the EBCM, along with a digital multimeter for circuit verification. Because this code involves a safety-critical braking system and a manufacturer-specific calibration sequence, it should be performed by a technician with proper training and equipment to avoid compromising brake system integrity.
🛠️ Resolution Steps
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Step 1: Preliminary Inspection
Begin by visually inspecting the brake pedal assembly and its wiring harness connector for corrosion, bent pins, chafed insulation, or loose connections. Check that the pedal position sensor assembly is securely mounted and that no aftermarket pedal modifications or recent repairs (such as pedal bracket replacement) have disturbed the sensor’s physical alignment. -
Step 2: Diagnostic Verification
Connect a scan tool to pull stored chassis codes and freeze frame data, then monitor live data streams for both Sensor A and Sensor B pedal position voltages simultaneously. With the key on, engine off, slowly depress and release the brake pedal while watching for smooth, proportional, and matching voltage changes between both sensors. Use a digital multimeter at the connector to verify reference voltage, ground integrity, and signal return voltage match the manufacturer’s specifications if the scan tool data looks erratic or frozen. -
Step 3: Resolution & Reset Process
If wiring and connector checks pass, perform the manufacturer-specified brake pedal sensor relearn/calibration procedure through the scan tool, which typically requires cycling the ignition and pedal through a guided sequence while the module captures Sensor B’s position data. If the sensor itself is found to be out of range or non-responsive, replace the brake pedal position sensor assembly (often sold as a unit with Sensor A) and then repeat the calibration procedure. Clear codes afterward and perform a full key cycle plus road test to confirm no code resets.
📦 Parts, Labor, and Budget Estimates
- Required Components/Software: Brake pedal position sensor assembly (dual sensor unit), OEM-level or advanced bidirectional scan tool with brake system calibration function, digital multimeter
- Average Component Price: $85 – $220 USD
- Estimated Labor Hours: 0.8 – 1.5 hours (includes diagnostic time and calibration procedure)
- Total Estimated Budget: $180 – $400 USD