This bulletin applies to several Chevy models including 2019-2021 Blazer, 2017-2021 Cruze, 2018-2021 Equinox, 2017-2021 Malibu, 2019 – 2021 Silverado 1500 and 2018-2021 Traverse vehicles, all equipped with Stop/Start.
Some customers may comment that the Start/Stop function is inoperative and the MIL is on. Technicians may find DTC P3055 (DC/DC converter output voltage 1 performance) set in the ECM. The concern may be caused by the DC/DC module being mis-configured and Channel 1 does not boost properly.
Refer to document ID # 4773341: circuit/system verification testing. Verify that a test lamp does not turn on between terminal 10 and ground. If the test lap turns on, repair the short to voltage on circuit 2172.
If the test lamp does not turn on, remove all appropriate fuses supplied by circuit 2172. Test for infinite resistance between terminal 10 and the T19 power supply transformer and ground. A less than infinite reading can be caused by component circuits being shorted to another component within the harness or a slight chafe to ground, preventing a fuse to open.
If less than infinite, repair the short to ground on the circuit. If you do find infinite resistance, replace the T19 power supply transformer P/N 13510484.
