Throttle Actuator Control Motor Circuit High
Diagnostic trouble code P2103 indicates that the powertrain control module (PCM) has detected an abnormally high electrical value in the throttle actuator control (TAC) motor circuit. This typically means there is a short to voltage in the circuit that controls the electronic throttle body motor.
This code is considered high severity because a failure in the throttle actuator control system will usually force the vehicle into a 'limp mode' with severely reduced power, making it unsafe for normal driving.
Common symptoms
- Illuminated Check Engine Light
- Vehicle enters limp mode (reduced engine power)
- Lack of throttle response or no acceleration
- Engine stalling or rough idle
- Cruise control disabled
Likely causes
- Short to voltage in the throttle actuator control motor wiring harness
- Faulty throttle actuator control motor (internal short)
- Corroded, damaged, or loose electrical connector at the throttle body
- Binding or stuck throttle body valve
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Visually inspect the wiring harness and connectors leading to the electronic throttle body.
Look for: Look for chafed wires, melted insulation, or signs of a short to power, as well as corrosion or loose pins in the connector.
Check the throttle body valve for physical binding or carbon buildup.
Look for: With the engine off, gently push the throttle plate to ensure it moves freely without sticking or excessive resistance.
Measure the resistance of the throttle actuator control motor using a digital multimeter.
Look for: Compare the resistance reading to the manufacturer's specifications. A reading of zero or near zero ohms indicates an internal short in the motor.
Test the TAC motor circuit for a short to voltage.
Look for: With the throttle body disconnected and the key on (engine off), probe the control wires. If battery voltage is present on a wire that should not have it, there is a short to power in the harness.
Use a scan tool to monitor the TAC motor command and actual position data.
Look for: Observe if the commanded throttle position matches the actual position, and check for abnormally high current or voltage readings on the TAC motor data PIDs.
This page explains the generic P2103 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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