P2102: Throttle Actuator A Control Motor Circuit Low

What does P2102 mean?

P2102 means the output stage for throttle motor A sees a voltage or current that points to a short toward ground or an overloaded driver. GM lists P2100-P2103 together in its 2018 calibration as faults that limit engine power and default the throttle authority; a Bosch-based GM ECM of 2012 assigns its output-stage checks (short circuit, overtemperature or overcurrent, open load) to this group with about 0.1 s detection. Apart from such tables, no maker publicly documents P2102 on its own; many current ECUs report the same fault under P2100 with a failure-type byte. CARB requires circuit faults of output components to be detected. The throttle drops to limp position and power is cut. The high-side counterpart is P2103.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Limp mode with throttle at fixed opening
• Engine warning lamp on
• Pedal input largely ignored

Common causes

• High Motor wire chafed through and shorted to ground
• Medium Shorted winding or jammed motor drawing excess current
• Medium Water in the throttle connector bridging terminals
• Low Faulty throttle driver in the engine control unit

Likelihood is a general estimate across vehicles; your make and model may differ.