P0724🔧 Transmission / Brake switch inputStop and fix promptly

P0724: Brake Switch B Circuit High (Meaning, Causes, Fixes)

Reviewed 2026-10-25 · Based on 2 cited source(s)

What P0724 means

The brake pedal switch does two jobs: it turns on the brake lights and it tells the computer the pedal is pressed. OBD-Codes.com explains that on automatic transmissions the powertrain control module (PCM) uses this signal to release torque converter lockup (the clutch that locks the engine to the transmission at cruising speed) before the car slows to a stop, otherwise the engine would stall. It describes P0724 as a generic code (it lists Ford, Honda, Mazda, Mercedes and VW among examples) that sets when the PCM detects a high electrical condition in the torque converter brake switch circuit designated B, applies only to automatic transmissions, and notes that some vehicles have more than one brake switch. RepairPal defines P0724 as Brake Switch "B" Circuit High, set when the PCM detects an implausible signal from the brake switch. The sources differ in a few ways: OBD-Codes.com names the code Torque Converter/Brake Switch B Circuit High and focuses on torque converter lockup, stalling and transmission damage, while RepairPal lists only brake lights and cruise control as symptoms. RepairPal also names a body control module (BCM) failure as a cause, where OBD-Codes.com points to the PCM instead. Related codes are P0703 (the general brake switch B circuit code), P0719 (brake switch B circuit low), P0700 (transmission control system MIL request), P0740 (torque converter clutch circuit) and P0571 to P0573 (cruise control/brake switch A).

Severity: can I keep driving?

Stop and fix promptly

Get it fixed right away. OBD-Codes.com says P0724 should be treated as urgent because severe internal transmission damage can result if torque converter lockup stays inoperable for a long time, and most models disable lockup and put the transmission in limp-in mode when this code sets. RepairPal rates P0724 Urgent. Both sources say your brake lights may not work, so check them before driving: a car whose brake lights don't come on is much more likely to be rear-ended.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. Failed brake switch (both sources)
  2. Misadjusted brake switch, which OBD-Codes.com says is often misdiagnosed as a failed one (OBD-Codes.com)
  3. Shorted or open wiring or connectors in the brake switch B circuit (both sources)
  4. Blown fuse or burnt fusible link (OBD-Codes.com)
  5. Faulty PCM or a PCM programming error (OBD-Codes.com)
  6. Body control module (BCM) failure (RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Have someone watch the brake lights while you press the pedal. If they don't come on, fix that first, since it is a safety problem on its own.
  2. Check for technical service bulletins (TSBs) for your vehicle, since the problem may be a known issue with a known fix.
  3. Visually inspect the brake light switch above the pedal, its connector and the brake lamp wiring, and check that the switch is adjusted so the pedal arm actually presses it.
  4. Test the stop lamp fuses, including with the brake pedal pressed. OBD-Codes.com notes a fuse can look fine but fail once the circuit is under load.
  5. Read and write down all stored codes and freeze frame data, clear them, and test drive to see if P0724 comes right back.
  6. With a digital volt/ohmmeter and a service manual, check for battery voltage at the switch input, then at the switch output with the pedal pressed. No output voltage points to a bad or misadjusted switch, per OBD-Codes.com.
  7. OBD-Codes.com's quick lockup test: at highway speed with the engine warm, lightly press and hold the brake while keeping your speed. If RPM rises, the torque converter clutch works and the brake switch is releasing it properly.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • The brake lights still don't work after replacing the fuse or switch
  • The engine stalls when you come to a stop
  • The transmission shifts erratically or stays in limp mode
  • You don't have a meter or wiring diagram to trace the circuit

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is P0724 the brake light switch?

Often. Both sources list a failed brake switch as a cause, and OBD-Codes.com adds that a misadjusted switch is often mistaken for a bad one, so check the adjustment, fuses and wiring too.

What is the difference between P0719 and P0724?

Both point to the brake switch B circuit. P0719 means the computer saw a low voltage signal, while P0724 means it saw a high voltage signal. P0703 is the general circuit fault for the same switch.

Is it safe to drive with P0724?

Not for long. RepairPal rates it Urgent, OBD-Codes.com warns of transmission damage and stalling, and your brake lights may not work, which puts you at risk from drivers behind you.

How much does it cost to fix P0724?

Neither source gives a repair cost. It can be as simple as a fuse or switch adjustment, so get a diagnosis or written estimate before replacing parts.

Sources

  1. OBD-Codes.com: P0724 Torque Converter/Brake Switch B Circuit High (Stephen Darby, ASE Certified Technician)
  2. RepairPal: P0724 Brake Switch "B" Circuit High (rated Urgent)

Last reviewed 2026-10-25. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.