C100A

Code

LAND ROVER C — Chassis

Brake pedal position sensor

Brand: LAND ROVER

Type: C — Chassis

Views: UK: 16 EN: 20 RU: 20

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Page language: EN

Causes

Faulty brake pedal position sensor (internal failure or wear)
Damaged, chafed or disconnected wiring harness to the sensor
Corroded or loose connector pins at the sensor or control module
Poor sensor ground or missing reference voltage
Short to battery or ground in the signal circuit
Mechanical binding, damaged pedal linkage, or misadjusted sensor mounting

Symptoms

Brake warning, ABS, or traction/stability control warning lamp illuminated
Cruise control inoperative or disabled message
Possible reduced engine or torque management response when braking (in some models)
Irregular brake light behavior or brake lights stuck on/off
Diagnostic trouble code stored (C100A) and possibly related codes
Intermittent faults that occur when moving or flexing the pedal/wiring

What to check

Connect a diagnostic scan tool; record C100A and any related codes, freeze frame, and live data
Visually inspect sensor, pedal linkage, connector, and wiring harness for damage or corrosion
Wiggle harness and connector while monitoring live BPP signal to reproduce fault
Backprobe the sensor connector to check reference voltage (usually 5 V or ignition reference), signal voltage, and ground
Measure continuity and resistance of signal and ground wires to the control module (ignition OFF)
Compare signal voltage at rest and during full pedal travel; check for smooth, proportional change

Signal parameters

Common reference: 5 V (or ignition reference) supply to sensor; confirm with vehicle data
Typical signal voltage range: ~0.5–4.5 V across pedal travel for potentiometer/Hall sensors (varies by model)
At rest (no brake): low-end voltage (typically ~0.5–1.5 V); when fully pressed: high-end (~3.5–4.5 V)
Some systems use dual redundant sensor circuits (BPP1 / BPP2) that must correlate within specification
Open circuit: signal near 0 V or battery voltage (short to B+); short to ground: ~0 V
Digital/CAN systems: BPP data may appear as a CAN message — check communication integrity if analog signal not present

Diagnostic algorithm

Read and record all DTCs and freeze frame data with a capable scan tool. Note whether multiple brake or communications codes are present.
Perform a visual inspection of the pedal area, sensor mounting, wiring and connector for damage, contamination or loose pins.
With ignition ON (engine off), backprobe the sensor connector: verify reference voltage (typically ~5 V), good ground, and measure the signal voltage at rest.
Slowly depress and release the pedal while watching the live signal value: signal should change smoothly without jumps, dropouts or dead zones. If dual sensors exist, ensure both channels correlate.
If signal is absent or out of range, check continuity of the signal and ground wires to the control module with ignition OFF. Repair any opens/shorts or poor grounds.
Wiggle the harness and connector while monitoring live data to locate intermittent faults. Repair/replace damaged wiring or connectors as required.
If wiring and supply/ground are good but signal is still faulty, substitute a known-good sensor (if available) or replace the BPP sensor.
After replacement or repair, clear codes, perform any required sensor or pedal calibration/learn procedure per manufacturer instructions, then road test to confirm the fault is resolved.
If fault persists with a verified good sensor and wiring, investigate the receiving control module (ABS/BCM/PCM) for internal fault or communication issues and consult technical service information.

Likely causes

Open or shorted signal wire between BPP sensor and control module
Bad ground or poor reference voltage at the sensor connector
Internal sensor potentiometer or hall element failure
Bent/dirty connector pins causing intermittent signal
Pedal return spring weak or pedal geometry preventing full travel detection
Recent work in the area (airbag, steering, dash) disturbed wiring or connectors

Fault status

⚠️ Status

C100A indicates the brake pedal position sensor circuit is reporting an invalid or out-of-range signal to a vehicle control module. This can be caused by a bad sensor, wiring/connector faults, poor reference/ground, or module communication issues. The condition may disable cruise control and affect brake/ABS/traction-control functions until corrected. Further diagnostic checks are required to identify the root cause.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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