Technical Description of OBD-II Trouble Code
The circuit for controlling the Throttle Actuator A is open.
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 operated by an electrical signal from the Powertrain Control Module (PCM).
The PCM receives inputs from various sensors to determine when and how long it needs to operate the TA-A. These inputs include voltage signals from coolant temperature, intake air temperature, engine rpm, and air conditioning system pressure sensors. Once the PCM has received these inputs, it can modify the signal to the TA-A.
P2100 is typically set due to electrical issues in the TA-A circuit. These issues should not be overlooked 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 is usually an electrical 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 P2100 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 fix 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 any scraping, rubbing, bare wires, burn spots, or melted plastic. Pull the connector apart and carefully inspect the terminals (the metal parts) inside the connector. Check if they appear burned or have a green tint indicating corrosion. If cleaning of the terminals is needed, use electrical contact cleaner and a plastic bristle brush. Let it 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 P2100 code returns. If it does not, then the connections were most 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. With a Digital Volt Ohm Meter (DVOM), connect one lead of the meter to one terminal of the actuator and connect the remaining meter lead to the other actuator terminal. It should not be open or shorted. Verify the resistance specifications for your particular vehicle. If the actuator motor is either open or shorted (infinite resistance or no resistance/0 ohms), replace the Throttle Actuator.
If that test passes, use a DVOM to check if you have 12V in the Throttle Actuator power supply circuit (Red lead to the actuator power supply circuit, black lead to a good ground). With a scan tool that can activate the Throttle Actuator, turn on the Throttle Actuator. If there is no 12 volts to the actuator, repair the wiring from the PCM or relay to the actuator, or possibly replace a faulty PCM.
If that’s OK, check if you have 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. Using the scan tool to actuate the Throttle Actuator, see if the test light comes on each time the scan tool actuates the actuator. If the test light does not light up, this would indicate a problem with the circuit. If it does light up, wiggle the wiring harness going to the actuator to see if the test light flickers, indicating an intermittent connection.
If all prior tests have passed and you continue to get a P2100, this would most likely indicate a failed Throttle Actuator, although a failed PCM cannot be ruled out until the Throttle Actuator has been replaced. If unsure, seek assistance from a trained automotive diagnostician. PCMs must be programmed or calibrated to the vehicle in order to be installed correctly.
