P2118 Buick Throttle Actuator Control Motor Current Range/Performance
– Electronic Throttle Control System (ETCS) harness is open or shorted
– Electronic Throttle Control System (ETCS) circuit poor electrical connection
The Electronic Throttle Control System (ETCS) has a dedicated power supply circuit. The voltage (+BM) is monitored and when the voltage is low (less than 4 V), the Engine Control Module (ECM) concludes that the ETCS has a fault and current to the throttle actuator is cut. When the voltage becomes unstable, the ETCS itself becomes unstable. For this reason, when the voltage is low, the current to the actuator is cut. If repairs are made and the system has returned to normal, turn the ignition switch OFF. The ECM then allows current to flow to the actuator and actuator can be restarted.