Technical Description of OBD-II Trouble Code
Range/Performance Issue with Throttle Actuator Control Motor
What does this mean?
This generic powertrain diagnostic trouble code (DTC) typically applies to all OBD-II equipped vehicles that use a drive-by-wire throttle control system, including but not limited to vehicles from Toyota, Honda, Hyundai, Lexus, Volvo, Scion, Nissan, Kia, etc.
The P2118 OBD-II trouble code is one of several possible codes that indicate a malfunction with the operation of the Throttle Actuator Control System as detected by the Powertrain Control Module (PCM).
There are six codes associated with Throttle Actuator Control System malfunctions: P2107, P2108, P2111, P2112, P2118, and P2119. Code P2118 is set by the PCM when the Throttle Actuator Control Motor is out of range or not performing properly.
The PCM monitors one or more throttle position sensors to control the Throttle Actuator Control System. The position of the throttle plate, controlled by one or more Throttle Actuator Control Motors, determines the operation of the throttle body. The PCM also monitors the accelerator pedal position sensor to determine the desired throttle response based on the driver’s input. The PCM adjusts the current flow to the Throttle Actuator Control Motor to move the throttle plate to the desired position. Certain malfunctions can cause the PCM to restrict the operation of the Throttle Actuator Control System, resulting in fail-safe or limp mode where the engine is held at idle or may not start at all.
Code Severity & Symptoms
The severity of this code can range from moderate to severe, depending on the specific malfunction. Symptoms of a P2118 trouble code may include:
Common Causes Of A P2118 Code
Possible causes of this code may include:
Common Repairs
Diagnostic and Repair Procedures
Check for TSBs
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins (TSB’s) for the specific vehicle by year, model, and power plant. This can save a lot of time in the long run by providing guidance in the right direction.
The second step is to locate all of the components associated with the Throttle Actuator Control System, including the throttle body, throttle position sensor, throttle actuator control motor, PCM, and accelerator position sensor in a simplex system. Perform a thorough visual inspection of these components and check the associated wiring for obvious defects such as scraping, rubbing, bare wires, burn spots, or melted plastic. Also, check the connectors to every component for security, corrosion, and damaged pins.
The last visual and physical inspection involves checking the throttle plate. With the ignition switch off, try rotating the throttle plate by pushing on it. It should rotate to the wide open position. If there is sludge behind the plate, clean it while it is accessible.
Advanced Steps
The advanced steps are vehicle-specific and require advanced equipment for accurate performance. These procedures involve using a digital multimeter and specific technical references for the vehicle. Voltage requirements vary based on the specific year, model, and engine of the vehicle.
Circuit Checks
With the ignition switch off, disconnect the electrical connector at the throttle body. Locate the 2 pins that go to the motor or motors on the throttle body. Use a digital ohmmeter set to ohms to check the resistance of the motor or motors. The motor should read approximately between 2 and 25 ohms, depending on the specific vehicle (check manufacturers specs for your vehicle). If the resistance is too high or too low, the throttle body will need to be replaced. If all tests have passed so far, check the voltage signals to the motor.
If this process identifies the absence of a power source or ground, continuity testing may be required to check the integrity of the wiring. Continuity tests should always be performed with the power removed from the circuit, and the normal readings should be 0 ohms of resistance unless otherwise specified by the technical data. Resistance or no continuity indicates faulty wiring that must be repaired or replaced.
We always recommend seeking professional service to resolve this issue. However, if that is not possible, we offer the option to permanently delete this specific DTC while keeping all other codes active. If you are interested in this option, please upload your ECU file to our portal.
