C100F — Brake Pedal Angle Sensor Supply

OBD2 code C100F flags a problem with the ABS / stability control (C100F — brake pedal angle sensor supply: causes, symptoms & fix). Short, gentle driving to a shop is usually possible. Common culprits: faulty ABS module or pump motor, damaged sensor wiring or corroded connector, damaged tone (reluctor) ring on the hub.

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Is it safe to drive?

Caution: brake pedal angle data may be unreliable C100F can affect ABS, stability control, brake assist, and other systems that read brake pedal angle. Ordinary braking may still feel normal, but avoid relying on disabled electronic systems. If the pedal feels soft or hard, brake assistance changes, or a brake warning remains on, stop safely and have the vehicle inspected.

Typical symptoms

The ABS, stability-control, or brake warning light illuminates with C100F stored in the ABS control module
C100F may return immediately after the brake pedal angle sensor connector is inspected or lightly moved
Traction control, electronic stability control, or hill-hold functions may be unavailable
Brake-assist functions that depend on pedal position can operate inconsistently or remain disabled
The brake pedal may feel normal while the vehicle still shows an ABS-related fault
On vehicles equipped with electronic parking brake or adaptive cruise control, those features may be restricted

Common causes

An open circuit or high resistance in the brake pedal angle sensor supply wire between the sensor and ABS control module
A short to ground or battery voltage caused by crushed, chafed, or heat-damaged wiring near the brake pedal
Corrosion, water intrusion, or a pushed-back terminal in the brake pedal angle sensor connector
A poor sensor ground or damaged ABS-module connector pin that prevents the supply reference from reaching the sensor
An internal failure of the brake pedal angle sensor that pulls down or interrupts its supply circuit
A low-voltage condition or failed power circuit feeding the ABS control module
An uncommon fault in the ABS control module's sensor-supply driver

How to diagnose with an OBD scanner

Confirm C100F with an ABS-capable scan tool Connect an OBD2 scanner such as ELM327 with an ABS-capable application or AIScanAuto. Read brake-system codes, confirm C100F, and review freeze-frame data for brake pedal position and vehicle speed. Clear the code only after recording the information, then determine whether it returns.
Inspect the sensor and connector Examine the brake pedal angle sensor connector and the harness between the pedal and ABS module. Look for corrosion, moisture, bent or pushed-back pins, conductor damage, and chafing where the harness bends or contacts moving brake components.
Measure the supply and ground circuits With the ignition on, use a multimeter and the vehicle wiring diagram to test the brake pedal angle sensor supply, normally a regulated 5-volt reference. Confirm that the voltage remains stable and that the sensor ground has low resistance to the designated ABS-module ground.
Check for an open or shorted supply With the sensor disconnected, check the supply pin for an unintended short to ground or battery voltage. Perform continuity and resistance tests on the supply and ground wires. A reading that changes when the harness is moved points to damaged wiring or a connector defect.
Test the sensor before the ABS module If the supply, ground, and connectors meet specifications, test the brake pedal angle sensor for internal shorts or abnormal current draw. Do not replace the ABS module until the sensor and complete wiring circuit have been verified, because module replacement is a less likely repair for C100F.
Repair and verification Repair the damaged circuit, clean and reseat the connector, or replace the faulty sensor as testing indicates. Clear C100F with the scanner, confirm the code does not return, and road test while monitoring ABS operation and brake-pedal-angle data.

Approximate repair cost

Independent-shop repairs for C100F typically range from about $250 to $700, depending on whether the fault requires wiring repair, connector service, or brake pedal angle sensor replacement. An ABS control module failure can raise the total to roughly $900-$1,400. These figures are estimates and vary by region, labor rates, and vehicle complexity.

Common questions

What does C100F specifically identify?

C100F identifies a fault in the supply circuit for the brake pedal angle sensor, commonly involving its regulated reference voltage, ground path, wiring, connector, sensor, or ABS-module driver.

Can I drive with C100F stored?

Driving may be possible if normal brake pedal feel remains, but ABS, stability control, hill hold, or other pedal-angle-dependent functions may be impaired. Repairs should be scheduled promptly.

Why does C100F return even after resetting the ABS module?

Resetting an ABS module does not repair an open, shorted, or unstable brake pedal angle sensor supply. The code commonly returns until the wiring, connector, sensor, or supply driver is corrected.

Does C100F always mean the brake pedal angle sensor is bad?

No. A broken supply wire, corroded connector, poor ground, or ABS-module driver fault can produce the same code. Voltage and resistance tests should be completed before replacing the sensor.

C100F — C100F — Brake Pedal Angle Sensor Supply: Causes, Symptoms & Fix

The engine control module logs trouble code C100F when it detects a problem within the anti-lock braking and electronic stability control network. Specifically, C100F points to an issue with the brake pedal angle sensor supply — a component that tells the system how far the pedal is depressed. When the voltage feeding this sensor falls outside the factory-acceptable range, the module flags the fault and illuminates a warning lamp.

On most vehicles, the brake pedal angle sensor works alongside the ABS module to coordinate braking force distribution. It continuously monitors pedal position and relays that data to the stability control system, which uses it to predict driver intent and intervene if the vehicle begins to skid. Because the system compares live sensor output against expected values over multiple drive cycles, a single brief glitch typically won't trigger C100F — the fault must be consistent. When the code does set, the module also saves a freeze frame snapshot recording engine RPM, load, coolant temperature, and vehicle speed at that exact moment. Reviewing that snapshot before diving into diagnostics narrows the field considerably.

Common Symptoms of C100F

The most noticeable clue is an illuminated stability control disabled message or an ABS/ESC warning lamp on the dash. Drivers often report that the brake pedal feels different — sometimes with altered pulsation during hard stops, since the anti-lock function may no longer modulate brake pressure. The speedometer can behave erratically, and cruise control may refuse to engage or drop out unexpectedly. In severe cases, the ABS pump stays dormant during emergency braking, leaving only conventional friction brakes to slow the vehicle.

What Causes C100F?

The culprits range from simple electrical issues to outright component failure. Start investigations with the most frequent offenders:

A blown fuse or insufficient voltage reaching the ABS module
Wiring damage, connector corrosion, or loose harness contacts related to the brake pedal sensor circuit
A worn or contaminated wheel speed sensor
Physical damage to the tone ring (reluctor ring) mounted at the wheel hub
A failed ABS control module or pump motor assembly

How to Diagnose C100F

A systematic approach prevents unnecessary parts replacement and wasted hours.

Hook up an OBD2 scanner and confirm C100F is present in the ABS module's fault memory. Save the associated freeze frame data — it reveals the exact driving conditions when the failure occurred.
Note any other trouble codes that appear alongside C100F. Related P-codes or C-codes often expose the root cause. Check manufacturer technical service bulletins for your specific make and model; certain C0xxx patterns have documented software patches or updated calibrations.
Inspect the wiring harness feeding the ABS module and brake pedal sensor. Look for chafed insulation, bent pins, moisture intrusion, or greenish corrosion buildup at connectors.
With the scanner reading live wheel speed data, drive slowly and watch all four sensor PIDs. A faulty sensor will drop out intermittently or display wildly implausible numbers.
Remove and visually inspect the suspect wheel speed sensor and its tone ring. Metal debris, cracks, or missing teeth on the ring will trigger C100F reliably.
Clear the code, then drive through a complete cycle that replicates the freeze frame conditions. If C100F returns, the fault is confirmed and component-level repair is next.

Repair Options and Costs

Target the cheapest probable cause first before considering major assemblies.

Sensor wiring repair or connector replacement: $80–$250
Wheel speed sensor replacement: $120–$350
ABS module diagnosis, repair, or full replacement: $400–$1,200

Independent shop labor rates typically run $75–$125 per hour; some repairs take under an hour while full module replacement can consume half a day.

Overall, addressing C100F runs between $80 and $1,200 depending on which part failed. An accurate diagnosis upfront prevents buying a $1,000 control unit when a $150 sensor or a $100 wiring fix would have resolved the issue.

Driving Safety Verdict: Caution

Standard friction brakes remain functional with C100F stored, so cautious driving is technically possible. However, anti-lock and stability control systems are disabled — stopping distances increase noticeably on wet, icy, or loose surfaces, and the vehicle won't automatically correct for skidding. Treat this code as a caution-level concern: drive conservatively, avoid spirited maneuvers, and schedule repair promptly.