DTC P1660: Output Driver Module Circuit No. 3: Description
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
Output Driver Modules (ODM) are chips inside Powertrain Control Module (PCM). ODMs provide grounded outputs that control devices. Each output has an internal feedback circuit that connects to PCM microprocessor. ODM 3 determines if voltage or current may cause damage to PCM. PCM monitors voltage through ignition 1 input. Any incorrect current that is on a circuit to ODM will cause ODM to report this DTC.