Engine Shudder Concerns

There may be several shudder concerns while driving on some 2020-2021 Silverado, Tahoe, Suburban, Sierra, Yukon and Escalade models that may be mistaken as a transmission-related concern. If the concern is on a vehicle equipped with the 4.3L V6 engine (RPO LV3), 5.3L V8 engine (RPO L82, L84, or 6.2L V8 engine (RPO L87), it may be related to the camshaft actuator system.

During diagnosis, monitor the GDS 2 Camshaft Position Variance data parameter while duplicating the shudder condition. Although the target variance is 0 (zero) degrees, it is not uncommon to observe a variance of up to 3-4 degrees on a properly functioning system. (Fig. 23, A) Any variance exceeding 3-4 degrees could potentially cause a noticeable shudder condition. (Fig. 23, B)


Fig. 23


If it’s determined that the concern is isolated to the camshaft actuator system, replace the camshaft actuator magnet and re-evaluate. If the shudder is still present after camshaft actuator magnet replacement and camshaft actuator variance is over 4 degrees, refer to the appropriate Service Information or contact the Technical Assistance Center for further assistance with diagnosis.

Refer to the latest version of #PIP5794 for more details and parts information.


– Thanks to Tim Lightfoot

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