Loose ECM-TCM Ground Connection

Some 2017 Colorado and Canyon models equipped with the 3.6L engine (RPO LGZ) may have an intermittent no crank condition. There may be a loss of communication with the Engine Control Module (ECM) and Transmission Control Module (TCM), the ignition key may be stuck in the ignition cylinder, and a dead battery.


The following DTCs also may be set: P018C, P0449, P0452, P0463, U0101, U0100, U0401, U0121, U0131, U18A2, P0522, P16E5, or P0118.


These conditions may be caused by a loose ECM-TCM ground (G104) (Fig. 14) on the driver’s-side cylinder head. Inspect G104 for a loose connection. (Fig. 15)


Fig. 14


Fig. 15


– Thanks to Aron Wilson

Vibration during 6th Gear Deceleration

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