This bulletin applies to 2015-2019 Cadillac Escalade and 2016-2019 CTS-V vehicles equipped with a 5.3L or 6.2L engine. Some customers may comment about a misfire/tick noise and the MIL on. The technician may find DTC P0300 set or in history.
This may be caused by one of the following:
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Active fuel management (AFM) lifter that is mechanically collapsed and/or stuck all of the time.
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Internal locking pin damage in the lifter due to oil aeration.
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Lifter that has collapsed and is stuck in the lifter bore.
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Bent pushrod
Inspect for camshaft damage while the lifters are removed. If damage is found, replace the camshaft.
Inspect the valve operation. If the valve(s) are not moving, replace the lifter oil manifold and the affected bank of AFM lifters. If a lifter has spun in its bore, the lifter guides should also be replaced.
If a lifter was stuck in its bore, after lifter removal, be sure to inspect the lifter bore for damage. If a lifter bore is damaged, GM recommends that the block must be replaced.
Another option is to use a vise grip with a small pry bar. If the lifter cannot be removed, the engine block must be replaced.
