Fault code P2102 is called “Throttle Actuator “A” Control Motor Circuit Low” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P2102
This diagnostic trouble code (DTC) is a generic code. Error P2102 is considered a generic code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.
The “A” throttle actuator is normally mounted at the front of the engine. On top of the engine, inside the wheel arches or against the bulkhead. The throttle actuator is controlled by an electrical signal from the transmission control module (PCM).
The PCM receives inputs to determine when and how much time it needs to operate the actuator. These inputs are voltage signals from the coolant temperature and intake air temperature sensors. Engine RPM and air conditioning pressure data are also used. Once the PCM receives these inputs, it can change the signal to the damper.
P2102 is usually set due to electrical problems in the circuit. Electrical problems should not be overlooked during the troubleshooting phase. Especially when troubleshooting occasional problems.
The troubleshooting steps may vary depending on the manufacturer, throttle actuator type, and wire colors.
Symptoms of vehicle malfunctions
The main signal that an error P2102 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- Check engine control lamp on the control panel will light up (the code will be written to the ECM memory as a fault).
- Engine cannot be accelerated, throttle response is unresponsive.
- Floating revolutions at idle (revolutions may be lower or higher than normal).
Fault P2102 is a serious error due to its effect on the cooling system. Since it is an electrical fault. The PCM cannot completely correct it. Partial correction by the PCM unit usually means that the engine sets a fixed idle speed (usually about 1000 to 1200 rpm).
Factors that can cause this error code
The error code P2102 can mean that one or more of the following problems have occurred:
- Throttle valve actuator circuit is open or short-circuited – probable.
- Faulty throttle actuator – probable.
- Failed PCM – unlikely.
How to fix or reset OBD-2 code P2102
Some suggested steps for troubleshooting and fix the error code P2102:
- Check the codes in the ECM.
- Diagnose code according to manufacturer’s verification test to check signal.
- Using the accelerator pedal, check throttle position sensors and actuator operation.
- Check harness and connection, visually for problems, correct if necessary.
- Test actuator according to manufacturer’s specified spot test.
Diagnose and repair of problems
The first thing to do is to check the technical service bulletins (TSB) for your particular vehicle. Your P2102 problem may be a known problem with a known fix issued by the manufacturer. This can save you time and money during diagnosis.
Then locate the “A” throttle actuator on your particular vehicle. This actuator is usually mounted at the front of the engine. On top of the engine, inside the wheel arches or against the bulkhead.
Once found, visually inspect the connector and wiring. Look for scratches, scuffs, exposed wires, burn spots, or melted plastic. Disconnect the connector and carefully inspect the terminals inside the connector.
Look to see if they look burnt or have a green tint indicating corrosion. If you need to clean the terminals, use an electrical contact cleaner and a plastic-bristle brush. Allow to dry and apply electrical grease to the contact areas of the terminals.
If you have a diagnostic scanner, clear the diagnostic trouble codes from the memory and see if the P2102 code returns. If it doesn’t, the problem is most likely related to the connection.
Check the actuator
If the P2102 code returns, we will need to test the actuator and associated circuits. There are usually 2 wires on each throttle actuator. First, disconnect the harness coming from the throttle actuator.
Using a digital multimeter, connect one lead of the meter to one terminal on the actuator. Connect the remaining meter lead to the other actuator terminal. It should not be open or shorted.
Check the resistance characteristics for your particular vehicle. If the actuator is shorted, the resistance will be infinite or nonexistent. If this is the case, replace the throttle actuator.
If this test is passed, use a multimeter to make sure you have 12 volts applied to the throttle actuator supply circuit. Red wire to the actuator supply circuit, black wire to ground.
Using a diagnostic tool that can activate the throttle actuator, turn on the actuator. If there is no 12 volts on the actuator, repair the wiring from the PCM or relay to the actuator. Also in this case, the PCM may be faulty.
If all is fine, make sure you have a good ground connection at the throttle actuator. Connect the test lamp to the plus end of the 12 V battery (red lead). And touch the other end of the test lamp to the ground circuit. The throttle valve actuator circuit goes to ground.
Using the diagnostic tool to actuate the throttle actuator. Check to see if the check lamp illuminates each time the diagnostic tool operates the throttle actuator.
If the indicator light does not come on, it indicates a faulty circuit. If it lights up, jiggle the wiring harness going to the actuator. To see if the check lamp flashes, indicating an intermittent connection.
If all the previous tests are passed and you keep getting error P2102. You most likely have a faulty throttle actuator. Although a failed PCM cannot be ruled out until the throttle actuator is replaced.
If you are unsure, get help from a qualified automotive diagnostician. The PCM must be programmed or calibrated for the specific vehicle in order to be installed correctly.
On which vehicles does this problem occur most frequently
Fault code P2102 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Audi (A3)
- Lexus (RX330)
- Toyota (Camry, Corolla)
Fault code P2102 can sometimes be found with other errors. The most common are the following: P2100, P2101, P2103, P2119.