P2100Generic code

P2100 Code: Throttle Actuator Control Motor Circuit/Open

The P2100 code means the electronic throttle motor circuit is open, so the motor gets no current when the computer commands it. It can put the engine in limp mode with limited power and a high or unstable idle. Check the connector, wiring and fuse before you replace the throttle body.

Severity
High
Can I keep driving?
Yes, but with caution
Estimated cost
$80 to $500
Difficulty
Medium
System
Idle and Speed Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

On this page

What the P2100 code means

With an electronic throttle (drive by wire), there is no cable between the pedal and the throttle. The computer reads the pedal, works out how far the throttle should open and moves it with a small electric motor. Two position sensors on the throttle and two more on the pedal confirm that everything agrees. If it sees a mismatch, it goes into a limp mode that limits power to avoid unwanted acceleration.

The computer watches the control circuit from its own driver transistor. The P2100 code is stored when the circuit is open, which means the motor gets no current when it is commanded. Before you replace the part, check the fuse, relay, connector and wiring, because those are the most common causes.

The motor is run by a transistor bridge inside the computer, which can reverse polarity to open or close the throttle.

Measure the motor resistance at its connector. If it is infinite, the motor is open inside. If it is correct, follow the control wire back to the computer looking for a break, especially in the stretches near the exhaust and at inline connectors.

P2100 code symptoms

  • Check engine light or another warning light on.
  • Limp mode with limited power.
  • High or unstable idle.

Likely causes of the P2100 code

  1. Unplugged connector or one with a broken lock.
  2. Open coil. Its resistance reads infinite.
  3. Cut wire. Check the areas where the harness rubs.
  4. Blown fuse. Often caused by an earlier short circuit.

How to diagnose the P2100 code step by step

  1. Activate the component with the scan tool and check whether it responds.
  2. Check the fuse and relay. Measure voltage on both sides of the fuse and swap the relay with an identical one.
  3. Measure the supply at the connector. You should see battery voltage with the key on or when the component is activated.
  4. Measure the component resistance and compare it with the manual. Also check its insulation to ground.
  5. Check the control wire for continuity back to the computer and for any short circuit.

How to fix the P2100 code

  • Repair the connector, the wiring or the power supply.
  • Replace the electronic throttle motor if it does not respond when it gets correct power and a correct command.
  • Clear the codes and verify the repair.

Technical reference data

  • Throttle motor: typical resistance of 1 to 5 ohms, driven by PWM with reversible polarity.
  • Position sensors: two signals, often one rising and one falling, that must add up to a constant value.
  • After cleaning or replacing the throttle body, the idle position usually has to be relearned.
  • These are general reference values, so check the manufacturer data for your vehicle.

Brand-specific notes

This system is everywhere. Chevrolet, Ford, Nissan, Toyota, Hyundai, Kia, Volkswagen and Renault use it on almost all of their current gasoline engines. Dirt in the throttle body is the most repeated cause on these vehicles.

If the throttle body looks dirty, clean it and run the relearn procedure, but do not skip the electrical tests, because a dirty throttle and an open circuit are different problems.

Frequently asked questions about P2100

Can I drive with a P2100 code?
With caution. The engine goes into limp mode and barely accelerates, so avoid passing and highway merging until it is repaired.
What does the electronic throttle motor do?
It opens and closes the throttle plate on the computer command, because there is no cable from the pedal. Position sensors on the throttle and the pedal tell the computer that the plate is where it should be.
Do I always have to replace the part?
No. Check the fuses, relays, connectors and wiring first, because they are the most common cause.
How much does it cost to fix P2100?
Expect roughly $80 to $500. A connector or wire repair is at the low end, and a new throttle body with labor is at the high end.
What does the P2100 code mean?
The P2100 code is a generic OBD2 code for an open circuit in the throttle actuator control motor. The motor does not get current when the computer activates it.

Related codes

Questions about the P2100 code

There are no questions about this code yet. Tell us about your case: vehicle, symptoms and what you have already checked.