P2299 Brake Pedal Position/Accelerator Pedal Position Incompatible

P2299 is an OBD-II diagnostic trouble code that indicates the engine control module (ECM/PCM) has detected an incompatible combination of brake pedal and accelerator pedal positions.

In simple terms, the vehicle's computer has detected a situation where it appears that the brake pedal and accelerator pedal are being applied at the same time, or the signals from the two pedal systems do not agree with each other.

This code is primarily associated with the vehicle's brake and accelerator pedal position signals, rather than being a direct engine or transmission fault.

What Does P2299 Mean?

P2299 – Brake Pedal Position / Accelerator Pedal Position Incompatible

Modern vehicles use electronic signals to determine whether the driver is:

• Pressing the accelerator

• Releasing the accelerator

• Applying the brake

• Releasing the brake

The ECM compares these inputs because simultaneous brake and accelerator application can be an intentional driving action in some situations, but it can also indicate a sensor, switch, wiring, or control problem.

If the ECM detects an implausible combination for a sufficient period, it may store P2299.

Why Does the Vehicle Monitor Both Pedals?

The brake and accelerator pedals provide two very different driver inputs.

The accelerator pedal requests engine torque.

The brake pedal indicates that the driver wants the vehicle to slow down or stop.

Modern electronic throttle systems therefore use brake-pedal information as an additional safety input.

If the ECM sees:

Accelerator pedal = significantly applied

while simultaneously seeing:

Brake pedal = applied

it may reduce engine torque or disable throttle response.

This is commonly referred to as a brake override or brake-throttle override strategy.

P2299 Does Not Always Mean Both Pedals Were Physically Pressed

This is an important distinction.

The ECM does not directly know what your foot is doing.

It knows what the pedal sensors and switches are reporting.

Therefore, P2299 can occur even when the driver is not intentionally pressing both pedals.

For example, a faulty brake-light switch may report that the brake is applied when the brake pedal is actually released.

Likewise, an accelerator pedal position sensor problem can cause the ECM to interpret the accelerator position incorrectly.

The computer then sees an incompatible combination even though the physical pedal positions are normal.

Common Causes of P2299

Potential causes include:

• Brake pedal switch malfunction

• Brake pedal position sensor problem

• Accelerator pedal position sensor problem

• Incorrect pedal sensor signal

• Wiring damage

• Connector corrosion

• Loose electrical connection

• Incorrectly adjusted brake switch

• Brake switch sticking

• Accelerator pedal sensor disagreement

• Damaged pedal assembly

• Floor mat or object interfering with the accelerator pedal

• Low system voltage

• ECM software or calibration issue

The exact cause depends on the vehicle.

Brake Pedal Switch Problems

The brake pedal switch is one of the first components worth checking.

Depending on the vehicle, the brake system may use:

• A simple brake-light switch

• A multi-contact brake switch

• A brake pedal position sensor

• A combination of switches and sensors

The ECM may receive brake-pedal information directly or through another control module.

If the switch is incorrectly adjusted or internally damaged, it can remain active after the brake pedal has been released.

This can create an apparent situation in which the driver is braking and accelerating simultaneously.

Check the Brake Lights

A very simple inspection can sometimes provide an important clue.

With the ignition on, check whether the brake lights behave normally.

Look for:

• Brake lights staying on after the pedal is released

• Brake lights failing to illuminate

• Brake lights activating with very little pedal movement

• Brake lights flickering

• Delayed brake-light operation

If the brake lights remain illuminated when the pedal is released, the brake switch or its adjustment deserves attention.

However, normal brake-light operation does not completely eliminate a brake-position sensor problem, because some vehicles use separate circuits or multiple switch contacts.

Accelerator Pedal Position Sensor

Modern vehicles commonly use an electronic accelerator pedal rather than a mechanical cable connected directly to the throttle body.

The accelerator pedal assembly can contain multiple position-sensor circuits.

The ECM compares these signals for plausibility and safety.

If one signal disagrees with the other, additional accelerator-pedal codes may appear.

Possible problems include:

• Worn pedal sensor

• Internal sensor failure

• Wiring fault

• Connector problem

• Incorrect reference voltage

• Poor sensor ground

• Signal dropout

P2299 can therefore occur as part of a larger accelerator-pedal problem.

Accelerator Pedal vs Throttle Position

The accelerator pedal and throttle body are not the same component.

The accelerator pedal position sensor tells the ECM what the driver is requesting.

The throttle position sensor reports the actual position of the electronic throttle.

The ECM uses both sets of information to control engine torque.

A P2299 diagnosis should therefore begin with the pedal inputs, rather than assuming that the throttle body is defective.

What Symptoms Can P2299 Cause?

The symptoms vary depending on the cause.

Possible symptoms include:

• Check Engine Light

• Reduced accelerator response

• Engine power reduction

• Throttle response limited

• Engine speed restricted

• Brake override activation

• Poor acceleration

• Intermittent loss of throttle response

• Vehicle entering a protective mode

Some vehicles may store the code without producing an obvious drivability problem.

Others may immediately reduce engine torque when the ECM detects simultaneous brake and accelerator input.

Why Can the Vehicle Lose Throttle Response?

If the ECM believes the brake and accelerator are being applied simultaneously, it may intentionally reduce engine torque.

This is a safety strategy.

The computer may interpret the situation as:

“The driver is braking while requesting acceleration.”

Rather than allowing unrestricted throttle opening, the ECM can override the accelerator request.

This means that reduced throttle response can actually be a protective reaction to P2299, rather than evidence that the throttle body itself has failed.

Can a Floor Mat Cause P2299?

Yes, under certain circumstances.

An improperly positioned floor mat or another object can interfere with pedal movement.

If the accelerator pedal remains partially depressed while the brake pedal is applied, the ECM may correctly identify simultaneous pedal input.

The driver's foot position should also be considered.

A driver may unintentionally touch both pedals, particularly during:

• Parking

• Maneuvering

• Tight turns

• Stop-and-go traffic

• Foot repositioning

A single occurrence does not necessarily indicate a component failure.

P2299 During Parking Maneuvers

P2299 can sometimes occur during low-speed maneuvering.

For example, a driver may lightly press the accelerator while also applying the brake to control vehicle movement.

Some vehicles tolerate this behavior, while others have stricter brake-override thresholds.

If the code appears only during parking or very low-speed operation, examine the pedal signals and driving circumstances before replacing components.

Check Live Data

A scan tool is particularly valuable for P2299 because the ECM's interpretation of the pedal signals can be observed directly.

Look for parameters such as:

• Accelerator Pedal Position

• Accelerator Pedal Position Sensor 1

• Accelerator Pedal Position Sensor 2

• Brake Pedal Status

• Brake Pedal Position

• Brake Switch 1

• Brake Switch 2

• Throttle Position

• Engine Torque Request

The exact parameters available depend on the vehicle.

With the brake released, the brake status should indicate the appropriate released state.

When the brake pedal is pressed, the status should change consistently.

Likewise, accelerator-pedal signals should change smoothly as the pedal is moved.

Look for Signal Disagreement

Many accelerator pedal assemblies use two separate position signals.

The ECM compares them for safety.

As the pedal moves, both signals should follow their expected relationship.

If one signal suddenly drops, jumps, or becomes implausible, the ECM can identify a pedal-position problem.

A scan tool can make this much easier to identify.

Instead of simply seeing:

Accelerator pedal = 30%

you may be able to observe multiple pedal-position parameters simultaneously.

Check the Brake Signal While Moving the Accelerator

A useful diagnostic observation is to monitor the brake status and accelerator position at the same time.

With the brake pedal fully released:

• Brake status should remain released.

• Accelerator position should respond smoothly.

When the brake pedal is pressed:

• Brake status should change correctly.

• Accelerator position should correspond to the actual pedal position.

If the brake status changes without touching the brake pedal, investigate the brake switch or position sensor.

If the accelerator position changes unexpectedly while the pedal is stationary, investigate the accelerator pedal sensor and its wiring.

Wiring and Connector Inspection

Electrical faults can create P2299 even when both pedals are mechanically perfect.

Inspect:

• Brake switch wiring

• Accelerator pedal connector

• Brake pedal connector

• Sensor grounds

• Reference-voltage circuits

• Signal wires

• Harness routing

• Connector terminals

Look for:

• Corrosion

• Water intrusion

• Loose terminals

• Broken wires

• Chafed insulation

• Previous wiring repairs

• Harness tension

A wiring fault may be intermittent and appear only when the vehicle is moving or the harness is disturbed.

Check the Brake Switch Adjustment

Some brake switches are adjustable.

If the switch is positioned incorrectly, it may activate too early or remain active after the pedal is released.

This can create an apparent brake-application signal when the driver is not actually braking.

The correct adjustment procedure varies by vehicle.

Do not adjust the switch based on a generic procedure without checking the manufacturer's specifications.

Battery Voltage Can Also Matter

Electronic pedal and brake systems depend on stable electrical power.

If P2299 appears together with several unrelated electrical or communication codes, check the vehicle's electrical system.

Inspect:

• Battery voltage

• Charging voltage

• Battery terminals

• Engine grounds

• Chassis grounds

A poor ground or unstable supply voltage can create unusual sensor readings.

Could the Throttle Body Cause P2299?

It is possible for throttle-related problems to coexist with P2299, but the throttle body should not be the first component replaced solely because this code is present.

The code specifically concerns brake-pedal and accelerator-pedal compatibility.

First establish whether the ECM is receiving incorrect pedal information.

If the pedal signals are correct but the throttle system is behaving incorrectly, then throttle-related diagnostics can be performed separately.

P2299 and Cruise Control

The brake pedal signal is also important for cruise-control operation.

When the brake is applied, the ECM generally needs to cancel cruise control.

If the brake switch falsely indicates that the brake is being applied, the vehicle may experience:

• Cruise control cancellation

• Cruise control unavailable

• Intermittent cruise operation

Therefore, if P2299 appears together with unexplained cruise-control problems, the brake-pedal signal deserves close attention.

P2299 and Stop/Start Systems

On vehicles equipped with automatic start-stop systems, brake-pedal information can also be used to determine whether conditions are appropriate for engine stopping and restarting.

An incorrect brake-pedal signal can therefore affect other vehicle functions.

The exact behavior depends on the vehicle's electronic architecture.

How to Diagnose P2299

A practical diagnostic procedure can be organized into several stages.

Start with a complete scan.

Check for other codes involving:

• Accelerator pedal

• Brake switch

• Brake position

• Throttle

• Engine torque

• ABS/ESC

• Communication

• Low voltage

Other codes may identify the actual problem.

Check the physical pedals.

Make sure:

• Nothing is obstructing the accelerator

• The floor mat is correctly positioned

• The accelerator moves freely

• The brake pedal returns fully

• There is no mechanical interference

Check the brake lights.

Verify that they turn on and off at the correct time.

Monitor brake-pedal live data.

Confirm that the ECM sees the correct brake status with the pedal released and pressed.

Monitor accelerator-pedal data.

If two pedal-position signals are available, compare their behavior.

Both should follow the manufacturer's expected relationship.

Inspect the wiring.

Pay attention to connectors and harnesses around the pedal assemblies.

Check power, reference voltage, and grounds.

Use the vehicle-specific wiring diagram.

Check brake-switch adjustment.

If applicable, verify adjustment according to the manufacturer's procedure.

Clear the code and road-test the vehicle.

Reproduce the conditions under which P2299 originally occurred.

Evaluate the ECM only after the external systems have been verified.

An ECM fault is possible but should not be the first assumption.

What If P2299 Appears Only Once?

If the code is stored as a history or pending fault and never returns, it may have been caused by a genuine momentary simultaneous pedal input.

This can happen during:

• Parking

• Stop-and-go traffic

• Emergency braking

• Foot repositioning

• Tight maneuvering

However, if the code repeatedly returns under normal driving conditions, a component or electrical fault becomes more likely.

What If P2299 Keeps Returning?

If P2299 repeatedly returns even though you are not pressing both pedals, focus on the pedal signals.

A useful approach is to monitor the data while:

• Releasing the brake

• Pressing the brake

• Slowly pressing the accelerator

• Releasing the accelerator

• Driving at low speed

• Driving at normal speed

The goal is to identify which signal becomes implausible first.

Is P2299 Dangerous?

P2299 deserves attention because it involves accelerator and brake input plausibility.

The vehicle may reduce engine power unexpectedly if it believes both pedals are being applied.

If the accelerator intermittently stops responding, the vehicle may become difficult to control in traffic.

If the code is accompanied by unpredictable throttle behavior, brake-light problems, or significant loss of acceleration, the vehicle should be diagnosed promptly.

Final Diagnosis

P2299 – Brake Pedal Position / Accelerator Pedal Position Incompatible means the ECM has detected a combination of brake and accelerator pedal signals that it considers incompatible.

The driver may genuinely have pressed both pedals, but the code can also be caused by a faulty brake switch, brake position sensor, accelerator pedal position sensor, wiring, connector, or electrical supply.

The most effective diagnosis is to check the physical pedals first, verify the brake lights, and then use live data to compare the brake status with the accelerator-pedal position signals.

The key is to determine which input is incorrect.

If the brake signal remains active when the pedal is released, investigate the brake switch or its circuit. If the accelerator position signals behave abnormally, investigate the accelerator pedal assembly and wiring.

P2299 therefore should not automatically be treated as a throttle-body problem. It is primarily a pedal-input plausibility and safety-system diagnostic code, and live data is often the fastest way to find the real cause.