P0724 Torque Converter/Brake Switch "B" Circuit High

The P0724 – Torque Converter/Brake Switch "B" Circuit High diagnostic trouble code (DTC) indicates that the transmission control module (TCM) has detected an abnormally high electrical signal in the brake switch "B" circuit associated with torque converter control.

Despite the name, P0724 does not necessarily mean that the torque converter itself is defective. In many vehicles, the TCM monitors the brake pedal switch signal to determine whether the brake pedal is being pressed. This information is important because the transmission may need to release the torque converter clutch when the driver applies the brakes.

When the TCM detects that the brake switch "B" circuit voltage is higher than expected, it can store P0724.

What Does P0724 Mean?

In simple terms:

The TCM is seeing an abnormally high signal from the brake switch "B" circuit.

The basic operating sequence is:

Brake pedal released → Brake switch sends expected signal → TCM monitors signal → Brake pedal pressed → Signal changes → TCM releases torque converter clutch when required

If the signal remains high or is higher than the expected electrical range, P0724 may be stored.

The exact wiring and switch arrangement varies considerably between vehicle manufacturers.

What Is the Brake Switch "B"?

Modern vehicles can use multiple brake-switch circuits.

One circuit may operate the brake lamps, while another circuit provides a redundant signal to the ECM/PCM or TCM.

Therefore, "B" does not necessarily mean a specific physical switch that is separate from switch "A."

Some vehicles use a dual-contact brake pedal switch, while others use multiple sensors or electronically monitored circuits.

This is why the vehicle's wiring diagram is important when diagnosing P0724.

Why Does the Transmission Monitor the Brake Pedal?

The brake pedal signal is important for torque converter clutch operation.

When cruising, the torque converter clutch can lock the engine and transmission together to reduce slip and improve efficiency.

When the driver applies the brakes, the system may need to release this clutch.

The TCM therefore monitors the brake signal to prevent inappropriate torque converter lock-up during braking.

An incorrect brake-switch signal can interfere with this strategy.

Symptoms of P0724

Possible symptoms include:

Check Engine Light

The malfunction indicator lamp may illuminate.

Torque converter clutch not engaging

The TCM may disable torque converter lock-up as a protective measure.

Torque converter clutch not releasing correctly

In some situations, incorrect brake-switch information can interfere with normal release logic.

Higher engine RPM during cruising

If lock-up is disabled, engine RPM may remain higher at highway speeds.

Reduced fuel economy

The engine may operate with increased torque-converter slip.

Harsh or unusual shifting

Incorrect brake-pedal information can affect transmission control strategies.

Transmission entering fail-safe mode

Some vehicles may restrict transmission operation.

Brake light abnormalities

Depending on the circuit design, the underlying switch or wiring problem may also affect brake-light operation.

Cruise control problems

The cruise-control system commonly relies on the brake pedal signal to cancel cruise control.

What Causes P0724?

Several problems can cause a high signal in the brake switch "B" circuit.

Faulty brake pedal switch

The switch may be internally damaged or stuck in an incorrect electrical state.

Incorrectly adjusted brake switch

If the switch is not positioned correctly relative to the brake pedal, its contacts may not operate at the correct time.

Short to voltage

A damaged wire may contact a power source and produce an abnormally high signal.

Damaged wiring

A shorted, melted, or incorrectly repaired wire can cause P0724.

Corroded connector

Corrosion can alter the electrical signal.

Loose terminals

Poor terminal tension can create an unstable or incorrect circuit condition.

Incorrectly installed brake switch

A switch that has been installed or adjusted incorrectly may remain in the wrong state.

Aftermarket electrical modifications

Remote starters, alarm systems, trailer wiring, or other modifications can occasionally interfere with brake-switch circuits.

ECM/PCM or TCM problem

A control-module fault is possible but should generally be considered only after the switch and wiring have been tested.

Can a Bad Brake Switch Cause P0724?

Yes.

The brake pedal switch is one of the first components that should be inspected.

A typical switch can contain multiple electrical contacts.

One part of the switch may control the brake lights, while another provides a signal to the vehicle's control modules.

A switch can therefore have an internal failure affecting the TCM signal even if the brake lights appear to operate normally.

Can a Misadjusted Brake Switch Cause P0724?

Yes.

This is an important possibility.

The brake switch must be positioned correctly relative to the brake pedal.

If it is installed too far in or too far out, the electrical contacts may change state at the wrong time.

For example, the TCM may see the brake signal as permanently active when the pedal is released.

A recently replaced brake switch should therefore be checked for correct installation and adjustment.

Can Wiring Cause P0724?

Yes.

A short to battery voltage is particularly relevant to a circuit-high code.

Inspect the wiring for:

• Short to voltage

• Damaged insulation

• Melted wiring

• Chafing

• Incorrect repairs

• Corroded terminals

• Loose connectors

• Water intrusion

Pay particular attention to wiring around the brake pedal, where movement and pedal mechanisms can stress the harness.

Can a Blown Fuse Cause P0724?

A blown fuse does not normally explain a circuit-high condition by itself.

However, fuse and power-supply problems can affect related brake-switch circuits and should be checked when other brake-light or electrical symptoms are present.

The correct fuse arrangement varies by vehicle.

Can P0724 Affect Cruise Control?

Yes.

The cruise-control system commonly uses the brake-pedal signal as a safety input.

When the brake pedal is pressed, cruise control should normally cancel.

If the vehicle incorrectly reports that the brake pedal is permanently pressed, cruise control may refuse to engage.

Conversely, an incorrect brake signal can cause unusual cruise-control behavior.

Therefore, if P0724 and cruise-control problems appear together, the brake-switch circuit deserves particular attention.

Can P0724 Affect Brake Lights?

It can.

The effect depends on how the vehicle's brake-switch circuits are designed.

Some vehicles use separate contacts for:

• Brake lights

• ECM/PCM

• TCM

• Cruise control

• Other systems

As a result, the brake lights may work normally even though the TCM-related switch circuit has a fault.

Alternatively, a switch or wiring problem can affect both brake lights and the control-module signal.

Does P0724 Mean the Torque Converter Is Bad?

No.

This is one of the most important points.

P0724 specifically identifies an electrical problem involving the brake switch "B" circuit.

It does not directly indicate:

• Worn torque converter

• Damaged torque converter clutch

• Internal transmission failure

• Low transmission fluid

• Damaged transmission gears

The brake-switch circuit should be investigated before considering internal transmission repairs.

Can P0724 Cause Torque Converter Problems?

Yes, indirectly.

The TCM uses the brake signal when deciding whether the torque converter clutch should remain engaged.

If the brake signal is incorrect, the TCM may alter torque converter clutch operation.

This can lead to:

• Torque converter clutch not engaging

• Higher cruising RPM

• Increased converter slip

• Reduced fuel economy

• Abnormal transmission behavior

The torque converter may therefore be functioning mechanically while its control strategy is being affected by an incorrect brake signal.

How Is P0724 Diagnosed?

A systematic electrical diagnosis is usually appropriate.

1. Scan all DTCs

Check for additional codes involving:

• Brake switches

• Cruise control

• Torque converter clutch

• Transmission control

• ABS/ESC

• ECM/PCM communication

Additional codes can help identify whether the problem is limited to the brake-switch circuit.

2. Check brake-light operation

Verify whether the brake lights operate correctly.

Do not assume they are fine simply because P0724 is present.

3. Inspect the brake switch

Check the switch for:

• Damage

• Incorrect installation

• Incorrect adjustment

• Loose mounting

• Physical obstruction

4. Monitor live data

Use a scan tool to observe brake-switch status.

With the pedal released, the brake status should show the expected state.

When the pedal is pressed, the status should change appropriately.

If the scan tool reports the brake as permanently applied, this is an important clue.

5. Test the switch electrically

Check the relevant switch contacts according to the manufacturer's wiring diagram.

6. Inspect wiring

Look for short-to-voltage conditions, damaged insulation, corrosion, and loose terminals.

7. Check power and ground

Verify that the switch and relevant control modules have the correct electrical supply.

8. Check the signal at the TCM or ECM

Determine whether the abnormal high signal is present at the module or is being introduced somewhere in the wiring.

9. Check communication

If the brake signal is transmitted electronically between modules, investigate CAN communication and module data.

Why Is Live Data Useful for P0724?

Live data can quickly show how the vehicle interprets the brake switch.

For example:

Brake pedal released → Scan tool shows BRAKE ON

This would strongly suggest that the system is receiving an incorrect brake-switch state.

Another useful check is comparing multiple brake-related parameters.

If one brake signal shows ON while another shows OFF with the pedal released, the discrepancy can help identify the faulty circuit.

What If the Brake Lights Work Normally?

This does not rule out P0724.

Modern vehicles can have multiple brake-switch contacts or separate signals.

The brake-light circuit may function correctly while the TCM-related signal remains incorrect.

Therefore, the brake-switch signal should be checked with a scan tool and electrical testing rather than relying only on whether the brake lights illuminate.

What If P0724 Appears After Replacing the Brake Switch?

Check the installation carefully.

Possible issues include:

• Incorrect switch type

• Incorrect adjustment

• Switch installed in the wrong position

• Connector not fully seated

• Damaged wiring during installation

• Incorrect replacement part

Some brake switches require a specific installation procedure to establish the correct pedal position.

What If P0724 Appears Together With P0723?

P0723 is Output Speed Sensor Circuit Intermittent, while P0724 concerns the brake-switch circuit.

If both codes appear together, they should not automatically be assumed to have the same cause.

Scan all modules and inspect the relevant wiring separately.

Shared wiring, power, ground, or communication problems should also be considered if multiple unrelated circuits fail at the same time.

What If P0724 Appears With Torque Converter Codes?

If P0724 appears together with torque converter clutch codes, do not immediately replace the torque converter.

First verify:

• Brake-switch status

• Brake-switch adjustment

• Wiring

• TCM input

• Torque converter clutch command

• Transmission fluid condition

An incorrect brake signal can affect the TCM's torque converter strategy and potentially contribute to other transmission-related DTCs.

Can P0724 Cause Limp Mode?

It can, depending on the vehicle.

If the TCM determines that an important brake-related input is unreliable, it may disable certain transmission functions.

Possible consequences include:

• Disabled torque converter lock-up

• Modified shift strategy

• Limited transmission operation

• Fail-safe mode

The exact response varies by manufacturer and transmission.

Is P0724 a Serious Problem?

Usually, P0724 is more likely to be an electrical/control problem than an internal transmission failure.

However, it should not be ignored.

The brake pedal signal is a safety-related input used by several vehicle systems.

If the vehicle has abnormal brake-light behavior, cruise-control problems, or unpredictable transmission operation, the problem should be repaired promptly.

Can You Drive With P0724?

If the vehicle's brakes and brake lights operate normally and the only symptom is a Check Engine Light, it may be possible to drive to a repair facility.

However, do not continue driving normally if:

• Brake lights do not operate correctly

• Brake lights remain on

• Cruise control behaves unpredictably

• Transmission enters severe limp mode

• Other brake-related warning lights appear

A brake-switch problem can affect more than just transmission operation.

How Is P0724 Repaired?

The appropriate repair depends on the confirmed cause.

Possible repairs include:

• Replacing the brake pedal switch

• Correctly adjusting the brake switch

• Repairing damaged wiring

• Repairing short-to-voltage conditions

• Repairing connector terminals

• Removing corrosion

• Correcting power or ground problems

• Repairing communication wiring

• Repairing or replacing a control module when properly diagnosed

In many cases, the repair is considerably simpler than an internal transmission repair.

Does P0724 Require Transmission Repair?

No, not normally.

The code points toward the brake switch "B" electrical circuit.

Before considering any transmission disassembly, the brake-switch circuit should be completely tested.

A faulty brake switch, connector, wiring problem, or incorrect switch adjustment can all produce P0724 without any mechanical transmission damage.

Common Diagnostic Mistakes

Assuming the torque converter is defective

P0724 is primarily an electrical brake-switch circuit code.

Replacing the torque converter

There is no justification for replacing the torque converter based solely on P0724.

Checking only the brake lights

The TCM may use a separate brake-switch circuit.

Ignoring switch adjustment

A newly installed switch can still be incorrectly positioned.

Replacing the brake switch without checking wiring

A short to voltage can produce the same code even with a new switch.

Ignoring cruise-control symptoms

Cruise-control behavior can provide useful evidence about the brake signal.

Ignoring ABS/ESC codes

Brake-related signals may be shared with several vehicle systems.

How Do You Clear P0724?

The underlying electrical fault should be repaired first.

After the repair:

Clear the DTC → Operate the brake pedal several times → Check live brake-switch status → Road test → Rescan

The brake-switch signal should change correctly between the released and pressed positions.

If P0724 returns, further electrical testing is necessary.

Final Thoughts on P0724

P0724 – Torque Converter/Brake Switch "B" Circuit High indicates that the TCM has detected an abnormally high electrical signal in the brake switch "B" circuit.

Despite the reference to the torque converter in the code description, P0724 does not mean that the torque converter itself has failed.

The most likely areas to investigate are the brake pedal switch, switch adjustment, wiring, connectors, short-to-voltage conditions, power supply, grounds, and communication between control modules.

The brake signal is important because the TCM uses it to control torque converter clutch operation. An incorrect signal can therefore cause higher cruising RPM, disabled torque converter lock-up, unusual shifting, reduced fuel economy, or transmission fail-safe operation.

A practical diagnostic path is:

Scan all DTCs → Check brake lights → Check brake-switch installation → Monitor brake-switch live data → Test the switch → Inspect wiring and connectors → Check for short to voltage → Verify power and grounds → Check module communication → Repair the confirmed fault → Clear the code → Road test and rescan.

The key point is simple: diagnose the brake-switch circuit before blaming the torque converter or transmission.