P2110 – Throttle actuator control (TAC) system – forced limited rpm mode / Heated oxygen sensor (H02S) 1, bank 1 – implausible signal

By Randy Worner (Contact Me)
Last Updated 2016-07-05
ASE/ACA World Class Technician

Table of Contents

1. What Does Code P2110 Mean?
2. What are the common causes of code P2110?
3. What are the symptoms of code P2110?
4. How do you troubleshoot code P2110?
5. Codes Related to P2110
6. Get Help with P2110

What Does Code P2110 Mean?

The engine computer (PCM) controls the Throttle Actuator Control (TAC) system, also known as the Electronic Throttle Control system (ETC). This includes the motors that move the throttle plate. The PCM looks at the throttle position sensor to determine the driver’s intent and then calculates the appropriate throttle response. The PCM accomplishes this by pulsing a voltage signal to the TAC motors. This moves the throttle plate to the desired position.

The main component of this system is the throttle body, which is located between the intake manifold and the air filter. Usually it will have one or more TAC / ETC motors to move the throttle plate inside, and one or more throttle position sensors to let the PCM know where the throttle plate is located at all times. When the command to the motors to move the plate does not correspond to the voltage signal sent back by the throttle position sensors (TPS), or if the amperage draw to the TAC motors is excessive, code P2110 can be set.

What are the common causes of code P2110?

• Faulty Throttle Actuator Control (TAC) module/Throttle Body (Very Common – can be caused by someone cleaning these throttle bodies who is unfamiliar with the correct cleaning procedure for the particular vehicle – moves throttle plates incorrectly, damaging TAC motors)
• Wiring to the Throttle Actuator Control (TAC) module is open or shorted
• Poor electrical connections at the Throttle Actuator Control (TAC) module
• Failed PCM – unlikely

What are the symptoms of code P2110?

• Malfunction Indicator Light “ON”
• Electronic Throttle Control Indicator “On”
• No throttle response – engine will only idle

How do you troubleshoot code P2110?

First, take a look and see if there are any technical service bulletins (TSB) for your particular vehicle. There may be a known fix put out by the manufacturer that can save you from wasting time and money.

Next, note if there are any other diagnostic fault codes. Insure that the battery is fully charged and not weak. Weak batteries can cause the current at the electronic throttle motors to go up. Higher than normal under hood temperatures have been known to contribute to this as well. Marginal/weak batteries have been known to set an intermittent P2110 fault code. Diagnose current faults first, in the order in which they are stored. Misdiagnosis occurs when this code is diagnosed when it is a stored code, especially while other codes are active.

Next, locate the Electronic Throttle Control (ETC) system on your particular vehicle. Usually, it is located between the intake manifold and the air filter. Once located, remove the tube that runs from the ETC system to the air filter. Once removed, visually inspect the throttle plates to see if they are clean and free of debris. With the ignition switch off, you should be able to slowly rotate the throttle plate by pushing in on it. It should slowly rotate to the wide open position. If there is a considerable amount of sludge behind the plate, clean it while you are there, taking care not to damage the throttle body by pushing in very quickly or by doing so while the ignition switch is in the “Run” position (unless instructed to do so by the vehicle manufacturer). Clean behind the plate area by spraying a rag with carburetor cleaner and wiping it out. DO NOT SPRAY ANYTHING INTO THE INTAKE! This only causes all the sludge to travel into the cylinders, possible coating the spark plugs, possibly causing a cylinder misfire and worse. Once completed, reattach the hose from the ETC system to the air filter housing. Perform an ETC system relearn procedure. Clear the diagnostic trouble codes from memory, and see if the P2110 code returns. If it does not, then the sludge buildup was most likely your problem.

If the code does return, check connections at both the PCM and the throttle body. Disconnect the negative battery cable before unplugging the connectors at the PCM or the throttle body. Once located, visually inspect the connectors and wiring. Look for scraping, rubbing, bare wires, burn spots or melted plastic. Pull the connectors apart and carefully inspect the terminals (the metal parts) inside the connectors. See if they look burned or have a green tint indicating corrosion. You can get some electrical contact cleaner and a plastic bristle brush at any parts store if cleaning of the terminals is needed. If this is not possible, find some rubbing alcohol and an old tooth brush to clean them with. Afterwards let them air dry, get some dielectric silicone compound (same stuff they use for light bulb sockets) and put some where the terminals come into contact. Clear the diagnostic trouble codes from memory, and see if the P2110 code returns. If it does not, then connection issues were most likely your problem.

If the P2110 code returns, you may want to check the resistance of the ETC motors. With the ignition switch in the off position, disconnect the electrical connector at the TAC / ETC system. Locate the 2 pins that go to each motor on the throttle body. Using a digital volt ohmmeter (DVOM) set to ohms, find the resistance of each motor. Each motor should be approximately between 2 and 25 ohms (check manufacturers specs for your vehicle). If the resistance is either too high or too low, the TAC/ETC system (throttle body) will need to be replaced.

If all tests have passed so far, you may want to check the voltage signals to each ETC motor, or resistance of the wiring between the ETC motors and the PCM. If any of these tests fail, it would indicate wiring repairs are needed between the PCM and the TAC system / Electronic Throttle Control / throttle body.

If all tests have passed to this point, and you continue to get a P2110 code, this would most likely indicate a failed Throttle Body Assembly, although a failed PCM could not be ruled out until the TAC / ETC system had been replaced. Anytime the throttle body is removed or replaced, the PCM will need to go through a TAC / ETC system relearn procedure in order to relearn throttle plate position. Also, if a PCM must be replaced, it must be programmed in order it work on that particular vehicle. At this point it is probably wise to consult with a trained automotive diagnostician.

Codes Related to P2110

• P2101 – Throttle actuator control (TAC) system – range/performance problem – Usually P2101 goes along with the P2110, as some of the same issues that set P2110 set the P2101.
• P2101 is typically related to mechanical issues while the P2110 is almost strictly electrical / motor issues.

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