FAW Accelerator Pedal: An Expert Guide to Its 3 Logic Components

Welcome to this expert technical guide on the FAW Accelerator Pedal assembly (Part No. 1108010-42A-C00), the critical driver-to-engine interface for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor. This is not a mechanical cable, but a sophisticated electronic sensor.

The FAW Accelerator Pedal, part of the “Engine Control Unit Logic Assembly,” is the primary “torque request” sensor for the “drive-by-wire” system. It translates the physical movement of the driver’s foot into a precise voltage signal, which is then sent to the Engine Control Unit (ECU) to manage fuel injection and engine power.

This guide is an essential resource for professional technicians, fleet managers, and parts specialists. We will deconstruct the entire FAW Accelerator Pedal assembly and its 3 serviceable components, including the electronic pedal, its mounting hardware, and the critical firewall seal, to ensure a complete understanding of this vital system.

Core Component: Electronic Accelerator Pedal (1108010-42A-C00)

The main component is the ‘Electronic Accelerator Pedal Assembly’ (1108010-42A-C00). This is the complete FAW Accelerator Pedal unit. It has replaced the old-fashioned mechanical throttle cable. This “drive-by-wire” system offers immense advantages in efficiency, safety, and integration with other systems like cruise control, traction control, and the engine brake.

The “logic” of this FAW Accelerator Pedal lies in its internal sensors. The assembly is not just a pedal; it is a housing that contains a “non-contact” electronic sensor, typically a set of dual **potentiometers** or **Hall-effect sensors**. As the driver presses the pedal, it rotates a magnet or a wiper arm inside this sealed sensor unit.

This sensor outputs a precise, variable voltage signal (e.g., 0.5V at idle, 4.5V at full throttle) that is sent directly to the ECU. This signal is the “torque request” from the driver. A high-quality FAW Accelerator Pedal sensor provides a smooth, linear signal, which allows the ECU to deliver power without any “dead spots” or “surging.”

The Critical Safety Logic: Dual Sensor Redundancy

A key feature of the FAW Accelerator Pedal (1108010-42A-C00) is its fail-safe design. Because it is a 100% electronic “drive-by-wire” system, a failure is a critical safety issue (e.g., a “stuck” full throttle). To prevent this, the FAW Accelerator Pedal uses **dual redundant sensors**.

Inside the sensor housing are two (or sometimes three) separate potentiometers (APP1 and APP2) that read the same pedal movement. These two sensors are often programmed to work in opposite or parallel ways. For example:

• **APP1 (Sensor 1):** May read from 0.5V (idle) up to 4.5V (full throttle).
• **APP2 (Sensor 2):** May read from 4.5V (idle) down to 0.5V (full throttle).

The ECU’s “logic” constantly compares the signals from these two sensors. At any given pedal position, the sum of their voltages should be a constant 5.0V (in this example). If one sensor fails, the signals will no longer “agree” (e.g., 0.7V + 3.0V = 3.7V). The ECU instantly recognizes this “disagree” fault, logs a Diagnostic Trouble Code (DTC), illuminates the “Check Engine” light, and immediately puts the engine into a “limp-home” mode (e.g., idle-only power).

This redundancy is the core safety logic of the FAW Accelerator Pedal. A fault in this component is often the cause of a sudden, unexplained loss of power or a “limp mode” event. The entire FAW Accelerator Pedal assembly must be replaced, as its internal sensors are sealed and not serviceable.

The Mounting System: Bolts (CQ1420840) and Seal (1108011-42A)

The FAW Accelerator Pedal assembly is a simple three-part system, with two of those parts being the critical mounting hardware. The three ‘Combination Bolt’ (CQ1420840) fasteners are used to secure the entire assembly to the truck’s firewall or cab floor.

A “combination bolt” has a pre-installed, captive spring-lock washer. This is essential for preventing the bolts from vibrating loose over time, which would result in a “flexing” or “loose” pedal, providing poor driver feedback and potentially damaging the sensor. The 3-bolt “tripod” pattern provides a very stable, rigid mount for the FAW Accelerator Pedal.

The ‘Sealing Plug Cover’ (1108011-42A) is the third and final component. This is not just a cosmetic cover; it is a critical environmental seal. This large rubber grommet or foam/plastic cover is designed to seal the large hole in the firewall where the FAW Accelerator Pedal assembly passes through.

This seal serves four critical functions for the driver:

1. **Noise:** It blocks the immense noise from the diesel engine bay.
2. **Fumes:** It prevents toxic, dangerous fumes (exhaust, oil) from entering the cab.
3. **Temperature:** It seals out the scorching heat from the engine bay in summer and the freezing cold in winter.
4. **Water:** It prevents water, snow, and road salt from splashing into the cab.

FAW Accelerator Pedal Parts List

The following table provides the complete, detailed breakdown of all 3 components identified in the ‘Accelerator Pedal’ diagram for the FAW CA4251P66K24T1A3E5 tractor. The FAW Accelerator Pedal is a key part of the engine’s electronic control system.

Technical Specifications and Assembly Context

The specifications for the FAW Accelerator Pedal are defined by its function as a high-reliability electronic sensor. This FAW Accelerator Pedal is a key input for the Engine Control Unit Logic Assembly.