P2105 – Throttle Actuator Control System – Forced Engine Shutdown

What is Code P2105?

P2105 is an OBD-II diagnostic trouble code (DTC) defined as "Throttle Actuator Control System – Forced Engine Shutdown". This code indicates that the powertrain control module (PCM) has detected a serious fault in the electronic throttle control (ETC) system and has commanded the throttle valve to close, forcing the engine into shutdown mode.

Severity and Symptoms

Code P2105 is considered a severe issue that requires immediate attention. Driving the vehicle is not recommended when this code is present. The vehicle will enter a "limp mode" or "fail-safe mode" which disables cruise control and limits engine speed and power.

Common symptoms include:

• Sudden loss of engine power
• Engine stalling or shutting down while driving
• Inability to accelerate
• Check engine light illumination

Affected Parts and Systems

The main components involved with code P2105 are:

• Electronic Throttle Body (ETB) – contains the throttle valve and motor
• Accelerator Pedal Position (APP) sensors
• Throttle Position (TP) sensors
• Powertrain Control Module (PCM)

The electronic throttle control system calculates the optimal throttle position based on inputs from the accelerator pedal, engine conditions, and other sensors. It then uses the throttle motor to open or close the throttle valve as needed. If the PCM detects a serious fault, it will command the throttle closed to prevent unintended acceleration.

Common Causes

Potential causes of code P2105 include:

• Faulty accelerator pedal position sensor
• Faulty throttle position sensor
• Damaged wiring or connectors in the ETC system
• Throttle body failure
• PCM failure

Diagnosis Steps

1. Connect an OBD-II scan tool and check for any other codes present. Address those first.
2. Visually inspect the wiring harness and connectors for the APP sensor, TP sensor, and throttle body. Look for damaged wires or pins.
3. Test the APP sensor output voltages with a multimeter. Specs vary by make and model.
4. Test the TP sensor output voltages with a multimeter. Should see a gradual voltage change as the throttle opens and closes.
5. Check for power and ground at the throttle body motor. Use a multimeter or oscilloscope to verify the control signal from the PCM.
6. If all wiring and sensors test okay, the throttle body or PCM may be faulty. Further diagnosis with manufacturer-specific tools is needed.

Repair Options and Costs

After diagnosing the root cause, repair options may include:

• Replacing a faulty APP or TP sensor: $85-$250
• Repairing damaged wiring: $50-$300 depending on location and severity
• Replacing the electronic throttle body: $250-$650
• Replacing the PCM: $500-$1500 (rare cases)

Typical labor costs are around $75-$150 per hour. Total repair costs can range from under $100 for a wiring issue to over $2000 for a PCM replacement (€85-€1700).

Prevention and Related Codes

Proper maintenance of the electronic throttle control system can help prevent code P2105. This includes:

• Keeping the throttle body clean of carbon buildup
• Inspecting wiring harnesses for damage
• Addressing sensor codes promptly

Other codes that may appear alongside P2105 include:

• P0120-P0124 (APP sensor faults)
• P0220-P0229 (TP sensor faults)
• P2135 (Throttle/Pedal Position Sensor Correlation)

In summary, code P2105 is a serious issue that requires immediate diagnosis and repair by a qualified technician. Ignoring this code can result in stalling, loss of power, and potential safety hazards while driving. If you suspect an electronic throttle system problem, have it checked out right away.

Frequently Asked Questions about P2105

What does the OBD-II code P2105 mean?

P2105 is defined as “Throttle Actuator Control System – Forced Engine Shutdown.” It indicates that the powertrain control module (PCM) has detected a serious fault in the electronic throttle control (ETC) system and has commanded the throttle valve to close, forcing the engine into shutdown mode.

How serious is code P2105?

Code P2105 is considered a severe issue that requires immediate attention. Driving the vehicle is not recommended when this code is present, as it can result in sudden loss of engine power, stalling, and potential safety hazards.

What are the common symptoms of code P2105?

Common symptoms include:

• Sudden loss of engine power
• Engine stalling or shutting down while driving
• Inability to accelerate
• Check engine light illumination
• Vehicle stuck in “limp mode” or “fail-safe mode”

What causes code P2105?

Potential causes include:

• Faulty accelerator pedal position sensor
• Faulty throttle position sensor
• Damaged wiring or connectors in the ETC system
• Throttle body failure
• PCM failure

What components are involved with code P2105?

The main components involved are:

• Electronic Throttle Body (ETB)
• Accelerator Pedal Position (APP) sensors
• Throttle Position (TP) sensors
• Powertrain Control Module (PCM)

How does the electronic throttle control system work?

The electronic throttle control system calculates the optimal throttle position based on inputs from the accelerator pedal, engine conditions, and other sensors. It then uses the throttle motor to open or close the throttle valve as needed. If the PCM detects a serious fault, it will command the throttle closed to prevent unintended acceleration.

Is it safe to drive with code P2105?

No, it is not safe to drive with code P2105 present. This code indicates a severe issue that can cause sudden loss of engine power and control. The vehicle should be diagnosed and repaired immediately.

Can a faulty throttle body cause code P2105?

Yes, a faulty electronic throttle body can cause code P2105 to be triggered. The throttle body contains the throttle valve and motor, which are critical components of the electronic throttle control system.

Can a wiring issue trigger code P2105?

Yes, damaged wiring or connectors in the electronic throttle control system can cause code P2105. Wiring issues can disrupt communication between sensors and the PCM.

What sensors can cause code P2105 if they fail?

Faulty accelerator pedal position (APP) sensors and throttle position (TP) sensors are common causes of code P2105. These sensors provide critical input to the PCM for calculating the optimal throttle position.

How do you diagnose code P2105?

To diagnose code P2105:

1. Connect an OBD-II scan tool and check for other codes. Address those first.
2. Visually inspect wiring and connectors for damage.
3. Test the APP and TP sensor voltages with a multimeter.
4. Check power and ground at the throttle body motor.
5. Use a scope to verify the control signal from the PCM.
6. If no wiring or sensor faults are found, the throttle body or PCM may be faulty.

What are the common repairs for code P2105?

Common repairs include:

• Replacing a faulty APP or TP sensor
• Repairing damaged wiring in the ETC system
• Replacing the electronic throttle body
• Replacing the PCM (rare cases)

How much does it cost to fix code P2105?

Repair costs vary, but typical estimates are:

• APP or TP sensor: $85-$250
• Wiring repair: $50-$300
• Throttle body: $250-$650
• PCM: $500-$1500

Labor costs range from $75 to $150 per hour.

Can code P2105 cause transmission problems?

Yes, code P2105 can affect transmission operation in some vehicles. The forced engine shutdown mode may prevent the transmission from shifting properly.

Can low battery voltage trigger code P2105?

Low battery voltage can potentially trigger code P2105 if it causes disruptions in the electronic throttle control system. However, this is not a common cause. Other codes related to battery voltage would likely be present as well.

Can a vacuum leak cause code P2105?

A vacuum leak is unlikely to be a direct cause of code P2105. However, a major vacuum leak could potentially affect sensors like the MAP sensor which provide input to the PCM for throttle control calculations.

What is throttle actuator control system forced idle?

“Forced idle” is another term to describe the “limp mode” or “fail-safe mode” that the vehicle enters when code P2105 is triggered. The PCM commands the throttle valve to a slightly open fixed position to limit engine speed and power for safety reasons.

Can a dirty throttle body cause code P2105?

While a dirty throttle body alone is unlikely to cause code P2105, heavy carbon buildup can potentially affect the movement of the throttle valve and disrupt feedback from the throttle position sensor. This could contribute to triggering the code.

What other codes may be present with P2105?

Other codes that may appear alongside P2105 include:

• P0120-P0124 (APP sensor faults)
• P0220-P0229 (TP sensor faults)
• P2135 (Throttle/Pedal Position Sensor Correlation)
• U0100-U0229 (communication faults)

How can I prevent code P2105 from reoccurring?

To prevent code P2105 from reoccurring:

• Keep the throttle body clean of carbon buildup
• Inspect wiring harnesses regularly for damage
• Address any sensor-related codes promptly
• Maintain the battery and charging system
• Use a high-quality OBD-II scan tool for diagnostics

In summary, code P2105 indicates a serious fault in the electronic throttle control system that requires immediate diagnosis and repair by a qualified technician. Ignoring this code can result in stalling, loss of power, and potential safety hazards while driving. If you suspect an electronic throttle system problem, have it checked out right away.