This bulletin applies to 2015-2019 Cadillac Escalade vehicles where a no-crank/start with immediate stall condition exists. Also, the engine may stay running with the ignition off until the door is opened.
This may be accompanied by the MIL on, a “Service 4WD” message, relay clicking, inoperative rearview camera and one or more DTCs (B1370, B1325, P0650, P263A, P263B, P0513, P129D, P2535 and/or P0262B).
Vehicles equipped with 4WD may have a “Service 4WD message and DTCs C0364 and/or U0403” set.
These conditions could 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 I/P fuse block X51L. Both provide power to several different fuses. The 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. Note that the relays may be turning on and providing power to their respective fuses, but there may be no ignition 1 power to the modules due to terminal issues at the fuse block(s).
Inspect all underhood fuse block X50A connectors 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 (depending on model year, circuit 439 can vary in terminal location... check the service manual).
Also inspect for any backed-out terminals or poor connections at the left I/P fuse block X51L. The most common terminals with these issues have been terminal 42 at connector X1 for circuit 5199 and terminal 44 at connector X2 for circuit 1850. Circuit 5199 wiring should be inspected under the driver’s sill plate for damage/corrosion.
