21NA109

Service Bulletin
Bulletin No.:
21-NA-109
Date:
May, 2021
INFORMATION
Subject:
Diagnostic Information on Engine Vibration
This bulletin replaces PIP5503B. Please discard PIP5503B.
Brand:
Cadillac
Chevrolet
GMC
Model:
Model Year:
VIN:
from
to
CTS-V
2016
2019
Escalade
Models
2015
2020
Escalade
Models
2021
2021
Camaro
2016
2021
Corvette
2016
2019
Express
2018
2021
Silverado
2014
2018
Silverado LD
2019
2019
Silverado
1500 (New
Model)
2019
2019
Silverado
1500
2020
2021
Suburban
2015
2020
Suburban
2021
2021
Tahoe
2015
2020
Tahoe
2021
2021
Savana
2018
2021
Sierra
2014
2018
Sierra
Limited
2019
2019
Sierra 1500
(New Model)
2019
2019
Sierra 1500
2020
2021
Yukon
Models
2015
2020
Yukon
Models
2021
2021
Involved Region or Country
Copyright 2021 General Motors LLC. All Rights Reserved.
from
—
Engine:
Transmission:
4.3L (LV1,
LV3), 5.3L
(L82, L83,
L84) or 6.2L
(L86, L87,
LT1 or LT1 w/
o Z52
(Corvette
only), LT4)
—
to
—
North America, Europe, Russia, Middle East, Israel, Chile, Colombia, Ecuador,
Venezuela, Japan, GM Korea Company, Cadillac Korea (South Korea), China, Thailand,
Singapore, Philippines, Other Africa, Australia/New Zealand
Page 2
May, 2021
Bulletin No.: 21-NA-109
Condition
Some customers may have a concern with an engine vibration. This vibration may occur
when vehicle is stationary or accelerating from a stop.
It may be found that the engine oil was recently changed.
Cause
This may be caused by the engine being overfilled with oil.
Information
If the above concern is encountered, it is recommended to check the engine oil level.
Refer to the vehicle owner manual for details on correctly checking engine oil level.
A vibration caused by a crankcase overfilled with engine oil will typically display Engine 1
(E1) as the dominant vibration when monitored with the PICO Scope.
• If the engine oil level is confirmed to be overfull, verify if the crankcase was overfilled
with engine oil or is contaminated by an outside substance such as fuel or coolant.
• If the engine was overfilled with only engine oil, adjust the oil level and re-evaluate the
concern (possibly the result of the engine oil having been overfilled during an oil
change or maintenance service).
• If the engine oil level was overfull as a result of contamination, determine the source of
the contamination and repair as needed.
Version
1
Modified
Released May 03, 2021
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.
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