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Error Code P2118 is defined as Throttle Actuator Control Motor Current Range/Performance, which usually happens due to wiring or throttle motor issue.
This error code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, especially those made since 1996 up to present. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another.
Vehicles with electronically controlled throttle bodies are equipped with a throttle actuator control motor, also known as drive-by-wire. In this kind of system, the gas pedal acts as a sensor and sends a signal to the throttle actuator control motor, which then opens and closes the throttle place according to the demand.
When the PCM (powertrain control module, also known as ECM or engine control module) has determined that the voltage is out of range, or there is the throttle actuator control motor is suffering from poor performance, it will set the Error Code P2118 and simultaneously activate the Check Engine light.
When this code is set, it also triggers the Failsafe mode of the vehicle, which keeps the vehicle safe from further damage as it limits the vehicle’s operation. This Failsafe mode will be removed when the fault is resolved.
As with other error codes, this code activates the Check Engine light on the dashboard and registers the code to the vehicle’s memory. Also, it can cause serious symptoms, such as vehicle not responding to gas pedal due to failsafe mode.
Other common symptoms include:
- Engine misfire
- Poor running from lack of power
In some vehicles, the Check Engine light may not show up until the symptoms start to show.
Multiple factors lead to the registry of this code, such as:
- Failed throttle actuator control motor
- Failed pedal position sensor
- Failed throttle position sensor
- Open or short in actuator circuit
- Poor electrical connection
How to Check
Mechanics diagnose this code by using a scan tool to check for the codes stored in the PCM of the vehicle. All the codes are noted, including the code history and pending codes. Each code will also have their freeze frame data associated with them; this tells the technician what the condition of the vehicle is at when the code was first stored.
All codes are then cleared, and the vehicle will be taken for a test drive. If after the test drive the code is still present, then the technician will proceed on its diagnosis.
The technician will then conduct a visual inspection and look for obvious failed components or damages in the wiring. The scan tool will be used to monitor the data stream and check both the throttle and gas position of the sensor values as they are operated. A multimeter will then be used to check for voltage at the throttle actuator control motor.
Lastly, the technician will remove the air intake and throttle body to inspect them and check whether the throttle plate is capable of moving.
How to Fix
This error code is easy to repair, but of course, demands thorough diagnosis. Typical repairs include:
- Repair or replacement of the damaged wiring harness
- Replacement of the throttle actuator control motor
- Replacement of pedal position sensor
- Replacement of the defective throttle position sensor
- Repairing or replacement of poor electrical connection
Many people misdiagnose or make mistakes with this error code by simply overlooking the importance of thorough visual inspection. In many cases, repair is simply about finding the frayed wires and repairing them. It is crucial to follow all steps in their proper order and completed entirely before making repairs.
Because this code puts the vehicle in failsafe mode, it prevents the throttle from operating properly, which can lead to serious problems. The vehicle may not move or drive when the symptoms start to show up. Thus this code must be taken with extreme care, and the vehicle must not be driven until this problem is solved.
An advanced-level scan tool is important to get an accurate diagnosis for this code. If you don’t have this tool, then it’s best to get the services of a certified technician to fix this code.