P2118 code definition
The P2118 code is a general OBD-II diagnostic trouble code (DTC) that is referencing the throttle actuator control motor current / performance. This code may be seen with other throttle position sensor codes.
What the P2118 code means
The throttle actuator control motor is used on cars with electronically controlled throttle bodies also called drive-by-wire. On these systems, the gas pedal is a sensor that sends a signal to the throttle actuator control motor which opens and closes the throttle plate according to demand.
When the engine control module (ECM) detects out-of-range voltage or poor performance from the throttle actuator control motor, the P2118 code is set along with a Check Engine Light on the dashboard. When the P2118 code is set, it also triggers a failsafe mode to prevent damage to the vehicle. The failsafe mode will remain until normal operation is found or until the fault is resolved.
What causes the P2118 code?
These are the most common causes of the P2118 code:
- Throttle actuator control motor failure
- Failed pedal position sensor
- Throttle position sensor faulty
- Open or short in the actuator circuit
- Poor electrical connection
What are the symptoms of the P2118 code?
The P2118 code can have some rather serious symptoms. The worst being the car not responding at all if the gas pedal is depressed due to the failsafe mode. Other possible symptoms are an engine misfire, poorly running engine, lack of power, and the Check Engine Light being illuminated. In some cases, the Check Engine Light may not be seen until after the symptoms start.
How does a mechanic diagnose the P2118 code?
Qualified technicians will begin by using a scan tool to check for any codes stored in the vehicle's ECM. All the codes will be noted including the codes stored in its history and codes that may be pending. Each code will also have freeze frame data associated with it which tells technicians what the vehicle conditions were when the code was set and which code was set first.
All codes will then be cleared and a test drive performed. Upon returning from the test drive, the technician will check that the P2118 code is present again.
Next, a visual inspection will be performed looking for any obviously failed components or damaged wiring. Then, the scan tool will be used to monitor the data stream and check the throttle and gas position sensor values as they are operated. A multimeter will then be used to check for voltage at the throttle actuator control motor.
Lastly, the air intake will be removed and the throttle body will be inspected to see if the throttle plate is capable of moving.
Common mistakes when diagnosing the P2118 code
Mistakes can easily be made when simple steps such as the visual inspection are overlooked. The repair could be as simple as finding a frayed wire and repairing it. All steps must be followed in the proper order and completed in their entirety.
How serious is the P2118 code?
The P2118 code can prevent the vehicle’s throttle from operating, which can cause some serious problems. The car may not drive or move after symptoms start, so extreme care should be taken and the vehicle should not be driven if drivability concerns are present.
What repairs can fix the P2118 code?
Generally, simple repairs such as these fix the P2118 code:
- Wiring harness repaired or replaced
- Throttle actuator control motor replaced
- Pedal position sensor replaced
- Faulty throttle position sensor replaced
- Poor electrical connection resolved
Additional comments for consideration regarding the P2118 code
An advanced-level scan tool is very important for accurately diagnosing the P2118 code. These scan tools allow technicians much greater access into the vehicle's ECM. Basic scan tools are only able to clear codes and show the current codes. The advanced scan tools allow access to the live data stream which displays useful sensor data in ways that otherwise would not be available.
Need help with a P2118 code?
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