Technical Description of OBD-II Trouble Code
The performance of the Throttle Actuator A Control Motor Circuit is outside the acceptable range.
What does that mean?
This generic powertrain/engine diagnostic trouble code typically applies to all OBDII equipped engines with electric Throttle Actuators, but is more commonly found in certain Ford and Nissan vehicles.
The Throttle Actuator A (TA-A) is usually located at the front of the engine, on top of the engine, inside the wheel wells, or against the bulkhead. The TA-A is controlled by an electrical signal from the Powertrain Control Module (PCM).
The PCM receives inputs from coolant temperature, intake air temperature, engine rpm, and air conditioning system pressure sensors to determine when and how long it needs to operate the TA-A. Once the PCM has received these inputs, it can adjust the signal to the TA-A.
P2101 is typically triggered by electrical (TA-A circuit) issues, but it can also be caused by mechanical issues, such as a mechanically stuck throttle blade on the electrically driven Throttle Actuator. Both electrical and mechanical issues should be considered during troubleshooting, especially when dealing with an intermittent problem.
Troubleshooting steps may vary depending on the manufacturer, type of TA-A, and wire colors.
Related throttle actuator A control motor circuit codes:
Code Severity & Symptoms
This code is usually severe due to its impact on the cooling system. Since it can be either an electrical or mechanical failure, the PCM cannot fully compensate for it. Partial compensation typically results in a fixed idle speed (usually around 1000 – 1200 rpm).
Symptoms of a P2101 engine code may include:
Causes
The typical causes for this code to be set are:
Diagnostic and Repair Procedures
A good starting point is always to check for technical service bulletins (TSB) for your particular vehicle. Your issue may be a known problem with a known solution provided by the manufacturer, which can save you time and money during diagnosis.
Next, locate the Throttle Actuator A (TA-A) on your particular vehicle. This actuator is usually found mounted to the front of the engine, on top of the engine, inside the wheel wells, or against the bulkhead. Once located, visually inspect the connector and wiring. Look for scraping, rubbing, bare wires, burn spots, or melted plastic. Disconnect the connector and carefully inspect the terminals inside. Check for signs of burning or corrosion. If cleaning of the terminals is necessary, use electrical contact cleaner and a plastic bristle brush. Allow them to dry and apply electrical grease where the terminals make contact.
If you have a scan tool, clear the diagnostic trouble codes from memory and see if the P2101 code returns. If it does not, then the connections were likely the problem.
For this particular code, the most common area of concern is the connections and the relays, with an actuator failure being a close second.
If the code does return, you will need to test the actuator and the associated circuits. Typically, there are 2 wires at each Throttle Actuator. First, disconnect the harness going to the Throttle Actuator. Using a Digital Volt Ohm Meter (DVOM), connect one lead of the meter to one terminal of the actuator and the other lead to the other terminal. There should be no open or short circuit. Verify the resistance specifications for your particular vehicle. If the actuator motor is either open or shorted (infinite resistance or 0 ohms), replace the Throttle Actuator.
If that test passes, use a DVOM to check if there is 12V in the Throttle Actuator power supply circuit (Red lead to the actuator power supply circuit, black lead to a good ground). Use a scan tool that can activate the Throttle Actuator to turn it on. If there is no 12 volts to the actuator, repair the wiring from the PCM or relay to the actuator, or consider a possible issue with the PCM.
If that’s OK, check if there is a good ground at the Throttle Actuator. Connect a test light to 12V battery positive (red terminal) and touch the other end of the test light to the ground circuit going to the Throttle Actuator circuit ground. Use the scan tool to actuate the Throttle Actuator and see if the test light illuminates each time the actuator is activated. If the test light does not illuminate, there may be a problem with the circuit. If it does illuminate, wiggle the wiring harness going to the actuator to check for an intermittent connection.
If all previous tests have passed and you continue to get a P2101, it most likely indicates a failed Throttle Actuator. However, a failed PCM cannot be ruled out until the Throttle Actuator has been replaced. If you are unsure, seek assistance from a trained automotive diagnostician. PCMs must be programmed or calibrated to the vehicle in order to be installed correctly.
