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A shop’s reputation is affected by things like accuracy of diagnosis, quality of the repair, and friendly service. Equally as important is the quality of the parts installed. When a new part fails, the customer is inconvenienced again, and begins to lose faith with the shop that performed the work. This ultimately begs the question – why take a chance with inferior parts?
Electronic Throttle Control (ETC) has been around for decades and can be found on most vehicles. It is important to understand the principles of the system before delving into specifics.
The Accelerator Pedal Position Sensor (APP)
The Accelerator Pedal Position Sensor (APP) is the driver’s input to the PCM or ETC standalone module. In older vehicles, a throttle cable physically operated the throttle blade, based on the amount of pressure applied to the gas pedal. Today, throttle cables have been replaced by APP sensors mounted on the accelerator pedal. Since input from the APP sensors is critical to vehicle safety, there are checks and balances in place to prevent unintended acceleration or no acceleration. The sensors change at varying rates to ensure that signal lines aren’t crossed and the system is operating correctly. Additionally, to ensure that the driver experiences a familiar feel when pressing on the accelerator pedal without a throttle cable, these pedals usually incorporate a calibrated spring assembly.
The Powertrain Control Module
The Powertrain Control Module is still the brains of the operation. Most ETC applications rely on the PCM for control. The PCM analyzes the inputs from the APP and commands the throttle body to act appropriately. The PCM then analyzes the feedback from the multiple Throttle Position Sensors to monitor and adjust the position of the throttle blade according to the driver’s request and the vehicle’s demand.
Electronic Throttle Bodies
Most electronic throttle bodies use two wires that control the throttle body motor function. To drive the throttle blade open, power is supplied on one wire, while the other wire is supplied ground. In order to close the throttle blade, the polarities will be reversed.
The ETB also incorporates multiple Throttle Position Sensors. These are similar to APP sensors in that multiple sensors are used for safety and each one operates independently.
The throttle body is where the actual work is performed upon command from the PCM. Again, there isn’t a direct correlation between the APP and the throttle opening. Just because the pedal is pressed to the floor, the throttle body won’t necessarily be wide open. The PCM commands how much the blade opens based on a number of inputs and driving conditions. As seen above, the APP was pressed to 100%, but the throttle angle gradually changed to protect the powertrain.
When diagnosing an ETC fault, it is important to follow Diagnostic Trouble Codes and Technical Service Bulletins and seek out software updates. Many times, the DTC will be divided into three areas: APP, logic (PCM or wiring) or throttle body (TPS). Remember, other areas of the vehicle’s control system may cause throttle-related symptoms that aren’t necessarily faults of the ETC system. For example, wheel-speed sensor faults could affect throttle opening and should be diagnosed first.
Earlier, we mentioned the importance of selecting a quality Electronic Throttle Body – why not give your customers the best? Standard® offers the most comprehensive ETB line in the aftermarket, with more than 200 premium ETBs covering more than 190 million vehicles. Every Standard® ETB is 100 percent new, never remanufactured, and includes gaskets where required for a complete repair. Additionally, Standard® ETBs undergo extensive calibration and testing including on-vehicle and end-of-line testing to ensure that every ETB performs up to the brand’s critical standards.
All Standard-manufactured ETBs are built in North America in an IATF 16949-certified facility. As an expert manufacturer, Standard® engineers identify weaknesses in original equipment ETBs and design upgrades to the failure-prone components. For instance, Standard® engineers noted many failures of original equipment ETB gears, so they capitalized on their extensive gear design experience to develop a stronger, longer-lasting ETB gear. During the manufacturing process, Standard® assembles and calibrates the components and validates output voltages to ensure that the replacement ETB performs as the OEM intended in all driving conditions.
In addition to the highest-quality replacement ETBs, Standard® offers a full line of key components necessary to repair the electronic throttle control system, including Throttle Position Sensors, Accelerator Pedal Sensors, Variable Intake Manifold Actuators, and ETB Connectors — everything needed for a complete repair. When OE fails, technicians trust Standard® to deliver all of the parts they need with quality they can trust.
For more information on installation processes and relearns, check out the Standard Brand YouTube channel Electronic Throttle Bodies playlist, or simply search “throttle” on the channel.