P2102
Throttle Actuator Control Motor Circuit Low
If your vehicle's onboard computer has flagged the diagnostic trouble code P2102, it refers to a detected anomaly regarding "Throttle Actuator Control Motor Circuit Low". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
Storing code P2102 is your car's way of telling you something is wrong with the throttle actuator control motor circuit low. The most common signs are vehicle idles but will not accelerate, check engine light. Given the high severity of this code, continuing to drive risks significant mechanical damage. Have it diagnosed immediately.
Symptoms
Vehicle idles but will not accelerate, check engine light
Common Causes
- Short to ground in the TAC motor circuit
- Failed throttle actuator motor
- Water in the throttle body connector
- Internal PCM short
How to Fix
- 1 Trace and repair shorted wire
- 2 Replace electronic throttle body
- 3 Dry connector and apply dielectric grease
- 4 Replace PCM
Technical Explanation
P2102 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. The PCM distinguishes between electrical faults (circuit codes) and performance faults (rationality codes) by comparing the sensor's reported value against what other sensors would predict under the same engine operating conditions. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
Driving with an active P2102 fault risks accelerating damage to short to ground in the tac motor circuit and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
Before replacing any component on P2102, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Throttle body replacement: $300 - $600