03-02-2025
11 min.
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P2164 Throttle/Pedal Position Sensor "B" Maximum Stop Performance

The P2164 Throttle/Pedal Position Sensor "B" Maximum Stop Performance diagnostic trouble code indicates that the Engine Control Module (ECM/PCM) has detected a problem with the maximum-stop position or expected performance of Throttle/Pedal Position Sensor "B".

In simple terms, the vehicle's computer is monitoring the accelerator pedal or throttle-position sensing system and has detected that Sensor B is not reaching or reporting its expected maximum position correctly.

This is part of the vehicle's electronic throttle control system on vehicles that use accelerator-pedal and throttle-position sensors.

Depending on the vehicle, the problem may be located at:

Accelerator pedal position sensor
Electronic throttle body
Throttle position sensor
Sensor wiring
Electrical connectors
Throttle actuator system
ECM/PCM

The exact component associated with Sensor "B" varies by manufacturer.

P2164 can cause reduced engine performance or limp-home/fail-safe mode because the ECM must be able to determine the driver's requested throttle position accurately.

What Does P2164 Mean?

P2164 means the ECM has detected that the signal from Throttle/Pedal Position Sensor "B" does not behave as expected at the sensor's maximum stop or maximum commanded position.

Modern electronic throttle systems commonly use multiple position signals for safety and redundancy.

The ECM compares the signals from the sensors to determine whether the accelerator pedal and throttle system are responding correctly.

A simplified system can include:

Accelerator pedal assembly
Pedal Position Sensor A
Pedal Position Sensor B
Electronic throttle body
Throttle Position Sensors
Throttle actuator motor
ECM/PCM
Wiring harness
Connectors

The ECM expects Sensor B to produce a specific signal as the accelerator pedal or throttle moves toward its maximum position.

If the signal does not reach the expected range, the ECM may store P2164.

What Is Throttle/Pedal Position Sensor "B"?

Modern vehicles often use two or more position sensors rather than relying on a single accelerator-pedal signal.

These sensors provide redundant information to the ECM.

For example:

Sensor A produces one voltage signal.
Sensor B produces another voltage signal.
The ECM compares both signals.
The relationship between them must remain within a specified range.

This redundancy helps prevent unintended acceleration caused by a single sensor failure.

The letter "B" does not necessarily mean a specific physical sensor location that is identical on every vehicle.

The manufacturer determines:

Sensor identification
Voltage range
Signal relationship
Maximum-stop value
Diagnostic strategy

Therefore, the vehicle-specific wiring diagram and service information are important when diagnosing P2164.

What Does "Maximum Stop Performance" Mean?

The phrase "maximum stop performance" refers to the sensor's expected behavior at or near its maximum mechanical or commanded position.

The ECM expects the sensor signal to reach a particular value when the throttle or accelerator pedal reaches its maximum position.

If the sensor stops short electrically, produces an incorrect voltage, or does not follow the expected signal pattern, the ECM can determine that the maximum-stop performance is incorrect.

This does not necessarily mean that the accelerator pedal is physically stuck.

The problem can be caused by:

Sensor calibration
Sensor wear
Wiring resistance
Connector problems
Throttle-body problems
Mechanical interference
Incorrect sensor output
Electronic throttle-control problems

Symptoms of P2164

The symptoms can vary depending on the vehicle and the severity of the fault.

Check Engine Light

The most common symptom is an illuminated Check Engine Light.

Reduced Engine Power

The ECM may limit throttle operation to protect the driver and engine.

The vehicle may feel:

Slow
Weak under acceleration
Unresponsive
Restricted at higher speeds

Limp Mode

Some vehicles may enter a fail-safe or limp-home mode.

The ECM can limit:

Throttle opening
Engine speed
Acceleration
Vehicle performance

Poor Throttle Response

The accelerator pedal may feel less responsive than normal.

Hesitation During Acceleration

The engine may hesitate when the driver attempts to accelerate.

Limited Maximum Speed

The vehicle may not reach normal maximum engine or road speed.

Unstable Engine Operation

Depending on the fault, the engine may experience:

Surging
Irregular throttle response
Intermittent acceleration

Reduced Fuel Economy

Incorrect throttle-position information can affect engine control and operating efficiency.

Warning Messages

Some vehicles may display:

Reduced engine power
Throttle control warning
Electronic throttle control fault
Engine power limited
Service engine warning

Common Causes of P2164

Several problems can trigger P2164.

Faulty Accelerator Pedal Position Sensor

If Sensor B is integrated into the accelerator pedal assembly, the sensor can wear or fail internally.

Possible problems include:

Incorrect maximum signal
Intermittent signal
Internal sensor wear
Signal dropout
Incorrect voltage output

In many vehicles, the accelerator pedal position sensors are integrated into the pedal assembly rather than being separately serviceable.

Faulty Electronic Throttle Body

On systems where the diagnostic fault relates to throttle-position sensing, the electronic throttle body may be responsible.

Possible problems include:

Throttle-position sensor failure
Throttle motor problems
Carbon buildup
Mechanical binding
Internal electrical failure

Dirty or Restricted Throttle Body

Carbon deposits can interfere with normal throttle movement.

Heavy deposits can cause:

Restricted throttle movement
Incorrect closed-position learning
Abnormal throttle position
Slow throttle response

Cleaning may help in some cases, but it should not be assumed to be the solution until the sensor and throttle body are properly diagnosed.

Damaged Wiring

The sensor circuit depends on stable electrical connections.

Possible wiring problems include:

Broken wires
Chafed insulation
Short circuits
Open circuits
High resistance
Heat damage

Loose or Corroded Connector

A poor connector connection can change the sensor signal.

Possible causes include:

Loose terminals
Corrosion
Water intrusion
Bent pins
Poor terminal tension

Incorrect Sensor Calibration

Some vehicles require a throttle or accelerator-pedal relearn/calibration procedure after certain repairs.

If the sensor's learned position does not correspond to the actual position, a maximum-stop performance fault can occur.

Mechanical Obstruction

Something physically interfering with the accelerator pedal or throttle mechanism can prevent the sensor from reaching its expected position.

Possible causes include:

Damaged pedal assembly
Incorrect floor mat placement
Foreign objects
Bent components
Damaged throttle mechanism

A physical inspection should be performed before replacing electronic components.

Low or Unstable System Voltage

Poor battery or charging-system voltage can affect electronic throttle-control operation.

Possible causes include:

Weak battery
Charging-system problem
Poor ground connection
Electrical voltage fluctuations

ECM/PCM Problem

An ECM/PCM fault is possible but is generally less common than a sensor, wiring, connector, or throttle-body problem.

The module should not be replaced without proper circuit testing.

Vehicles Commonly Affected by P2164

P2164 can appear on many vehicles equipped with electronic throttle and accelerator-pedal position sensing systems.

Examples can include:

Ford F-150
Ford Focus
Ford Fusion
Ford Escape
Ford Explorer
Ford Mustang
Chevrolet Silverado
Chevrolet Tahoe
Chevrolet Malibu
Chevrolet Cruze
GMC Sierra
GMC Yukon
Dodge Ram
Dodge Charger
Dodge Challenger
Jeep Wrangler
Jeep Grand Cherokee
Chrysler 300
Toyota Camry
Toyota Corolla
Toyota Highlander
Toyota RAV4
Nissan Altima
Nissan Rogue
Nissan Pathfinder
Honda Accord
Honda Civic
Honda CR-V
Volkswagen Golf
Volkswagen Passat
Audi A4
BMW 3 Series
Mercedes-Benz C-Class

This is not a complete application list.

Important: P2164 is a generic OBD-II code, but the exact Sensor "B" location, circuit design, voltage range, and diagnostic procedure can vary significantly between manufacturers and model years.

How Is P2164 Diagnosed?

A proper diagnosis should begin with a scan of the vehicle's ECM/PCM and inspection of the throttle/pedal system.

Scan for Additional Trouble Codes

Use a professional diagnostic scanner to check for:

P2164
Other throttle-position codes
Accelerator-pedal sensor codes
Electronic throttle-control codes
Throttle actuator codes
Communication codes
Low-voltage codes

Additional codes can provide important clues.

Check Live Data

Monitor the accelerator-pedal and throttle-position parameters.

Technicians should compare:

Sensor A position
Sensor B position
Accelerator pedal percentage
Throttle position
Commanded throttle angle
Actual throttle angle
Sensor voltage

The two position signals should change smoothly and maintain the relationship specified by the manufacturer.

A sensor signal that suddenly drops, becomes fixed, or fails to reach the expected maximum can indicate a sensor or circuit problem.

Inspect the Accelerator Pedal

If the vehicle uses pedal-mounted position sensors, inspect the pedal assembly for:

Physical damage
Binding
Foreign objects
Incorrect floor mat positioning
Damaged wiring
Connector problems

Make sure the pedal can travel through its full range.

Inspect the Throttle Body

If the fault relates to the electronic throttle body, inspect it for:

Carbon deposits
Mechanical binding
Physical damage
Connector problems
Throttle motor faults

The throttle plate should move according to the manufacturer's diagnostic procedure.

Inspect Wiring and Connectors

Check the Sensor B circuit for:

Open circuits
Short circuits
High resistance
Damaged wires
Corrosion
Loose terminals
Water intrusion
Poor grounds

Electrical measurements should be compared with the manufacturer's specifications.

Check Reference Voltage and Ground

Many throttle and pedal position sensors use:

Reference voltage
Sensor ground
Signal circuit

The technician can verify that the required reference and ground circuits are present and stable.

A missing reference voltage may indicate a broader circuit problem rather than a failed sensor.

Perform a Sensor Sweep Test

The sensor should produce a smooth signal throughout the pedal or throttle travel.

A signal that:

Drops out
Jumps suddenly
Stops increasing
Remains fixed
Does not reach the specified maximum

can indicate a sensor or wiring problem.

Check for Required Relearn Procedures

Some vehicles require:

Accelerator pedal relearn
Throttle-position relearn
Electronic throttle-body adaptation
Idle relearn

after repairs or battery disconnection.

The correct procedure varies by manufacturer.

How to Fix P2164

The repair depends on the confirmed cause.

Replace the Accelerator Pedal Assembly

If the Sensor B circuit is integrated into the accelerator pedal and the sensor is defective, the complete pedal assembly may need to be replaced.

Replace or Repair the Throttle Body

If the throttle-position sensor or actuator inside the electronic throttle body is defective, the throttle body may require replacement or an approved repair.

Clean the Throttle Body

If carbon buildup is interfering with throttle movement, cleaning may resolve the mechanical problem.

The correct cleaning procedure should be followed because some electronic throttle bodies can be damaged by improper handling.

Repair Damaged Wiring

Possible repairs include:

Replacing damaged wires
Repairing approved harness sections
Correcting wiring routing
Restoring proper insulation
Repairing grounds

Repair Electrical Connectors

Damaged connectors may require:

Terminal replacement
Connector replacement
Corrosion repair
Terminal-tension correction

Perform a Throttle or Pedal Relearn

If the vehicle requires a relearn procedure, the appropriate manufacturer-specific procedure should be performed after repairs.

Repair Charging or Voltage Problems

If unstable system voltage caused the fault, the underlying problem should be corrected.

Possible areas to inspect include:

Battery
Alternator
Battery terminals
Engine grounds
Charging-system wiring

Repair or Replace the ECM/PCM

The ECM/PCM should only be considered after the sensor, wiring, connectors, throttle system, reference voltage, and grounds have been properly tested.

What Happens If P2164 Is Ignored?

Ignoring P2164 can result in continued or worsening throttle-control problems.

Potential consequences include:

Reduced engine power
Poor acceleration
Limp mode
Unpredictable throttle response
Difficulty maintaining normal vehicle performance
Increased risk of becoming stranded if the vehicle enters fail-safe mode

Because electronic throttle control is directly related to engine power management, the fault should be diagnosed rather than repeatedly cleared.

Can You Drive With P2164?

It may be possible to drive the vehicle with P2164 if the engine is still operating normally.

However, continued driving is not recommended if the vehicle has reduced power, severe hesitation, unstable throttle response, or limp mode.

If the Check Engine Light is accompanied by a Reduced Engine Power or throttle-control warning, the vehicle should be inspected as soon as possible.

A throttle-position sensor fault can potentially cause the ECM to limit engine power unexpectedly.

Is P2164 a Serious Code?

P2164 should generally be considered a moderate-to-serious diagnostic trouble code, particularly if it affects accelerator-pedal position information.

The main concern is not immediate engine damage but loss or limitation of normal throttle control.

The severity can increase if the vehicle:

Enters limp mode
Loses acceleration
Has intermittent throttle response
Displays multiple throttle-related codes
Becomes difficult to control or drive safely

How to Prevent P2164

There is no guaranteed way to prevent electronic sensor failures, but proper maintenance can reduce related problems.

Recommended practices include:

Keep the accelerator pedal area free of obstructions.
Make sure floor mats cannot interfere with pedal movement.
Keep electrical connectors dry.
Repair damaged wiring promptly.
Maintain the vehicle's battery and charging system.
Avoid unnecessary modifications to throttle-control wiring.
Clean the throttle body when required by the manufacturer.
Address Check Engine Light warnings promptly.
Perform required throttle or pedal relearn procedures after repairs.

P2164 vs. Related Throttle and Pedal Codes

Code	General Description
P2164	Throttle/Pedal Position Sensor "B" Maximum Stop Performance
P0121	Throttle/Pedal Position Sensor "A" Range/Performance
P0122	Throttle/Pedal Position Sensor "A" Circuit Low
P0123	Throttle/Pedal Position Sensor "A" Circuit High
P0220	Throttle/Pedal Position Sensor "B" Circuit Malfunction
P0221	Throttle/Pedal Position Sensor "B" Range/Performance
P0222	Throttle/Pedal Position Sensor "B" Circuit Low
P0223	Throttle/Pedal Position Sensor "B" Circuit High
P2135	Throttle/Pedal Position Sensor A/B Voltage Correlation
P2138	Throttle/Pedal Position Sensor D/E Voltage Correlation

These codes are related to throttle and accelerator-pedal position monitoring, but their exact application and diagnostic strategy can vary by vehicle.

Final Thoughts

The P2164 Throttle/Pedal Position Sensor "B" Maximum Stop Performance diagnostic trouble code indicates that the vehicle's ECM/PCM has detected that Throttle/Pedal Position Sensor B is not reaching or reporting its expected maximum position correctly.

Common causes include:

Faulty accelerator-pedal position sensor
Faulty electronic throttle body
Dirty or restricted throttle body
Damaged wiring
Loose or corroded connectors
Incorrect sensor calibration
Mechanical obstruction
Low or unstable system voltage
ECM/PCM problems

A proper diagnosis should include scanning for related codes, checking live sensor data, inspecting the accelerator pedal and throttle body, testing wiring and connectors, verifying reference voltage and grounds, and performing any required relearn procedure.

Because P2164 can lead to reduced engine power or fail-safe operation, it should not simply be cleared without identifying the underlying problem.

Important safety note: Electronic throttle-control systems are safety-critical engine-control components. If the vehicle experiences sudden loss of acceleration, severe throttle-response problems, or unpredictable engine behavior, it should be inspected before continued normal driving.