P2105 Code: Throttle Actuator Control System – Forced Engine Shutdown

The electronic throttle control (ETC) or throttle actuator control (TAC) system replaces the mechanical linkage between the accelerator pedal and throttle body with an electric actuator motor to control the throttle valve opening. This system has an accelerator pedal position (APP) sensor.

The sensor informs the powertrain control module (PCM) of how much power the driver is requesting from the engine. If the PCM is unable to receive a signal from the ETC system, a P2105 code will be logged by on-board diagnostics.

What Does the P2105 Code Mean?

Diagnostic trouble code (DTC) P2105 stands for “Throttle Actuator Control System – Forced Engine Shutdown.”

The ETC system is composed of an APP sensor, an electronic throttle actuator (servomotor), a throttle position (TP) sensor, and a PCM.

When the driver steps on the gas pedal, the APP sensor sends a signal to the TP sensor, which provides throttle angle feedback to the PCM. The PCM then determines the optimum throttle opening for efficient vehicle operation.

If the PCM detects that the ECT system is operating in forced idle shutdown mode, it will log a P2105 code. This typically indicates the vehicle is in a “limp mode” or “fail-safe mode.” This disables the vehicle’s cruise control system and limits engine speed.

Note: The definition of code P2105 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P2105 Code?

• Faulty sensor (manifold absolute pressure sensor, APP sensor, TP sensor, etc.)
• Faulty throttle actuator
• Wiring issues
• PCM failure

What are the Common Symptoms of the P2105 Code?

• Engine won’t start
• Vehicle stuck in “limp mode”
• Illuminated check engine light
• Illuminated anti-lock braking system (ABS) warning light

How to Diagnose the P2105 Code

DTC P2105 is a generic powertrain code that can be logged in vehicles with an OBD-II system. While this might be the case, keep in mind that the steps for diagnosis and repair can vary, depending on the vehicle’s specifications.

If you’re not familiar with the process of using diagnostic tools and unsure of what to look out for, it might be best to leave the job to the pros. But if you’re a seasoned DIYer who knows how to work your way around diagnosing trouble codes, then you can go ahead and do it on your own.

How to Fix the P2105 Code

Attempting to fix a trouble code like the P2105 can be frustrating if you don’t have the right tools and information. Under these circumstances, it might be better to bring your vehicle to the nearest auto repair shop instead.

But if you think you can fix the issue on your own, make sure to have the right guides before starting. Manuals like those from Chilton or an ALLDATA subscription contain vehicle-specific repair information, so you might want to check those out before you begin.