Diagnostic Aids

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

If DTC P0638 or P2101 is also set, diagnose that DTC first. A short between Brown wire and Yellow wire may have caused the ECM internal driver to overheat and set P2100. See DTC P0638: THROTTLE ACTUATOR CONTROL COMMAND PERFORMANCE or DTC P2101: THROTTLE ACTUATOR CONTROL MOTOR POSITION PERFORMANCE .

If DTC P2100 is set, the ECM will default to one of the two limp home modes (random injector disable with engine speed limited to 2600 RPM). The REDUCED POWER telltale will be illuminated and the ECM will remain in this condition for the entire ignition cycle even if the fault is corrected.

Ensure ECM is bolted securely to the ECM bracket and that ECM bracket is bolted securely to engine block. If P0638 and/or P2101 is not set and the ECM is secured correctly, replace ECM.