File in Section:

Service Bulletin

Bulletin No.:
Date:

PIT5345
November, 2014

PRELIMINARY INFORMATION
Subject:

Diagnostic Tip: Important Information Needed When Calling TAC for Diagnostic Help
on Vibration Complaints

Models:

2015 Cadillac Escalade Models
2015 Chevrolet Silverado, Suburban, Tahoe
2014 Chevrolet Silverado 1500
2015 GMC Sierra, Yukon Models
2014 GMC Sierra 1500

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern
Diagnosing a vibration issue can be a difficult task, with increased difficulty for TAC to diagnose over the phone.
Before calling TAC for assistance, there is some basic diagnostic information that must be obtained in order for TAC
to provide proper direction in repairing the vehicle.

Recommendation/Instructions
Vibration diagnostic information is found in Service Information (SI) under:
General Information > Vibration Diagnosis and Correction> Diagnostic Information and Procedures
This section also gives information on run out specifications, vibration theory and terminology, Vibration analysis
using EVA or NVH Oscilloscope, Balancing, etc.
When TAC assistance is needed on a vibration complaint, please gather the information listed below before
contacting TAC. It is divided into two areas: 1. With EVA or PICO scope measurements. 2. Without EVA or PICO
scope measurements.

1. With EVA or PICO scope measurements (PREFERRED METHOD)
Using a vibration analyzer, like the EVA or PICO scope, is the preferred method for gathering necessary vibration
frequency data. The vibration analyzer is similar to a scan tool when diagnosing a MIL. The use of a scan tool is
necessary to read the DTC to continue in the right direction, just like the vibration analyzer is necessary to obtain the
frequency data to continue in the right direction.
Please perform the Road Testing sheet (listed below) and complete ONLY THE APPLICABLE PORTION of the
Vibration Analysis Worksheet found in the Latest Version of Bulletin 03-00-91-001 (Document ID: 3287275) before
contacting TAC for further direction.
Vibration Analysis - Road Testing (CH-51450-NVH PICO/Oscilloscope) Document ID: 3686560 (PREFERRED
METHOD)
Or
Vibration Analysis - Road Testing (EL-38792-A Electronic Vibration Analyzer) Document ID: 2213708

2. Without EVA or PICO scope measurements (NOT PREFERRED)
Using a vibration analyzer, like the EVA or PICO scope, is the preferred method for gathering necessary vibration
frequency data. The vibration analyzer is similar to a scan tool when diagnosing a MIL. The use of a scan tool is
necessary to read the DTC to continue in the right direction, just like the vibration analyzer is necessary to obtain the
frequency data to continue in the right direction. It would be highly recommended to obtain a vibration analyzer to
obtain frequency data, but if one is not available, the necessary vibration frequency data will have to be obtained
based on symptoms observed during testing. Review Symptoms - Vibration Diagnosis and Correction (Document
ID: 2213711) to become familiar with the possible frequency ranges.
After performing the symptom based diagnostics (Document ID: 2213711), complete the appropriate vibration
analysis sheet below, as well as the APPLICABLE PORTION of the Vibration Analysis Worksheet found in the latest
version of Bulletin 03-00-91-001 (Document ID: 3287275) before contacting TAC.
– Vibration Analysis - Tire and Wheel (Document ID: 2084481)
– Vibration Analysis - Driveline (Document ID: 2086608)

– Vibration Analysis - Engine (Document ID: 2213709)
– Vibration Analysis - Hub and/or Axle Input (Document ID: 2073813)
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is
resolved without completing every step, the remaining steps do not need to be performed.