Circuit Description
WARNING: This page is about a different car, the 1999 Pontiac Grand Am and 1999 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.
DTC B1493 determines if a fault exists that causes the generator PWM reading to be continuously HIGH. DTC B1493 will set in the IPC when the PCM is sending ENGINE-RPM-IS-ZERO class 2 serial data and PCM is sending class 2 serial data message indicating generator PWM is not less than 64 percent for 30 seconds. DTC B1493 will set and the IPC will turn on the charge indicator light. The IPC history codes will be cleared after 100 ignition cycles with no current DTCs present throughout duration.