This bulletin applies to 2014 Chevy Silverado 1500, 2015-2018 Silverado, 2019 Silverado LD, 2019 Silverado 2500/3500, 2015-2019 Suburban and 2015-2019 Tahoe vehicles. Some owners may experience a no-crank or a start then immediate stall.
The SES MIL may not be on when the ignition is in the run position. Any of the following DTCs may be set: B1370, B1325, P0650, P263A, P263B, P0513, P129D, P2535 and/or P0262B.
Trucks equipped with 4WD may have a Service 4WD message and DTCs C0364 and/or U0403 set. The sound of a relay clicking may be noticed. The rearview camera may be inoperative when the transmission is shifted to reverse. The engine may stay running with the ignition off until the door is opened.
These concerns may be caused by a loss of ignition 1 voltage. There are two KR73 ignition main relays, one located in the underhood fuse block X50A and the other in the left interior fuse block X51L. Loss of ignition 1 voltage may be caused by either or both KR73 ignition main relays not turning on to provide power to their respective fuses.
Terminal issues may exist at a fuse block connector where the ignition 1 circuits exit the fuse block. The KR73 ignition main relays may be turning on and providing power to their respective fuses but there may be no ignition 1 power to their respective module/component due to the terminal issue at the fuse block.
Inspect all underhood fuse block X50A connections for any backed-out terminals, poor terminal fit and/or bent/twisted terminals. The most common terminals with these issues have been terminal M5 at connector X4 for circuit 5199; and terminal M7, A2 or A3 at connector X2 for circuit 439.
Inspect the interior fuse block also for backed-out terminals, poor fit, etc. The most common issues have been terminal 42 at connector X1 for circuit 5199 and terminal 44 at connector X2 for circuit 1850.
Also, inspect circuit 5199 under the driver’s sill plate for being damaged or corroded.
