Some 2020-2024 CT4 and CT5 models may have a no start condition and/or a loss of power steering. Communication DTCs U0101, U0131, U0401, U0402, U1611, U1818, U1962, U220F, U3003 sym16, U3003 sym1c may be set.
These conditions may be caused by a poor ground path through the front compartment front panel-to-vehicle body connection. (Fig. 7)
Fig. 7
If there is excessive voltage loss to a module or device on the ground path, perform a loaded voltage drop test between any of the ground connections G103, G107 (Fig. 8), G108 and G110 (Fig. 9) at the front compartment front panel to the negative post of the battery.
Fig. 8
Fig. 9
If the voltage drop is significant, remove and clean the front compartment front panel attaching points and fasteners. (Fig. 10, A. Right side; B Left side)
Fig. 10
For additional information, refer to #PIC6536.
– Thanks to Jeff Knight
I just had a 2022 Silverado from a body shop with too much paint around the ground terminals on the same front panel which caused loss of communication with the Brake System Control Module. 35 ohms resistance on the ground circuit.