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DTC codes / P21xx · Fuel and air metering / P2103

P2103Throttle Actuator Control Motor Circuit High

P2103 means the engine computer has detected an abnormally high voltage condition on the throttle actuator control motor circuit, which is the wiring and motor that physically move the throttle plate. The computer commands a specific throttle position, but the motor circuit is drawing too much current or the signal wire is shorted to voltage, so the computer sets this code and typically forces the engine into a reduced-power limp mode.

SystemPowertrain
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • The check engine light illuminates and the electronic throttle control warning light may also come on.
  • The engine may enter limp mode, limiting speed to a low threshold and making the accelerator pedal feel unresponsive.
  • The engine may idle at an abnormally high or erratic speed because the throttle plate is not following commands.
  • The accelerator pedal may feel dead or have a delayed, jerky response when pressed.
  • The engine may stall immediately after startup or refuse to start because the throttle plate cannot be positioned for idle.
  • Often no symptoms besides the warning light if the fault is intermittent and the throttle motor still moves freely.

Common causes, most likely first

  1. A short to voltage on the throttle actuator motor control wires, often from chafed insulation against a metal bracket or heat shield.
  2. A failed throttle body assembly where the internal motor windings are shorted or the internal position sensor is faulty.
  3. Corroded or loose pins in the throttle body electrical connector, allowing voltage to bleed across terminals.
  4. A damaged engine computer driver circuit for the throttle motor, though this is less common than wiring or throttle body faults.
  5. Water intrusion into the throttle body connector or harness from a missing splash shield or clogged cowl drain.
  6. Aftermarket accessories or alarm wiring tapped into the throttle pedal or throttle body harness, creating an unintended voltage path.

How to diagnose and fix it

  1. Inspect the throttle body connector and harness for chafing, corrosion, or water intrusion, and repair any damaged insulation or pins before replacing parts.
  2. Use a scan tool to command the throttle plate through its full range while watching throttle position sensor voltages for smooth, consistent readings.
  3. Measure resistance across the throttle actuator motor terminals and compare to the manufacturer's specification to check for a shorted winding.
  4. Back-probe the motor control wires with the key on and engine off to check for voltage present when the computer is not commanding the motor, which confirms a short to voltage.
  5. Disconnect the throttle body and check for a short to voltage on each motor control wire to ground and to battery positive using a multimeter.
  6. If wiring and connector tests pass, replace the throttle body assembly and perform the required throttle relearn or idle relearn procedure with a scan tool.
  7. Clear the code and road test the vehicle through several ignition cycles to confirm the repair, since intermittent faults may not reset immediately.

What a high voltage throttle code really means

  • A high voltage reading on the throttle motor circuit does not automatically mean the throttle body is bad, because a shorted wire or a poor ground elsewhere in the harness can produce the same code.
  • Technicians often replace the throttle body only to find the code returns because the real fault is a chafed wire behind the engine where the harness rubs on a bracket.
  • A weak or failing battery can cause the computer to misread throttle motor voltage during cranking, setting P2103 intermittently without any real circuit fault.
  • Aftermarket throttle controllers or pedal boosters that splice into the throttle harness are a frequent cause of this code on modified vehicles, and removing them often resolves the fault.
  • The throttle actuator motor and the throttle position sensor share the same housing on many vehicles, so a failing position sensor can cause the computer to command the motor in a way that triggers a high voltage code even when the motor itself is fine.

Can I keep driving with P2103?

Do not continue driving with this code because the vehicle is likely in limp mode with severely limited power, which is dangerous in traffic. If the engine starts and idles normally, drive only directly to a repair shop at low speed and avoid highways, but if the engine stalls or the throttle is unresponsive, have the vehicle towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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