Bulletin No.: PIP6060
Published date: 05/12/2025

Preliminary Information
PIP6060 Diagnostic Aids for 8-Speed transmissions with Shudder or Surge while
driving on highway
Models
Brand:

Model: Model Years:

Chevrolet Silverado 2023
Chevrolet Colorado 2023
GMC
Sierra
2023
GMC
Canyon 2023

-

2025
2025
2025
2025

VIN:
Engine: Transmissions:
from to
All
All L3B
8L80 8L90
All
All L3B
8L45 8L90
All
All L3B
8L80 8L90
All
All L3B
8L45 8L90

Involved Region or
Country

North America

Condition

Customer may complain of a surge or shudder concern under light throttle
during highway driving

Cause

This may be caused by a potential engine concern

Correction:
Some Customers may complain of a shudder or surge concern under light throttle during highway driving
Please refer to Torque Converter Diagnostics in SI to verify this is not a transmission related concern
If the a concern is not isolated with converter diagnostics inspect the HO2S Sensor 1 (Pre-Catalyst) Lambda
and STFT (Short Term Fuel Trim) for rapid fluctuations
See the GDS2 examples below
Suspect HO2S Sensor 1 values

Known Good HO2S Sensor 1 values

If a concern is suspected with the Oxygen sensor, or DTC P064D is setting please inspect for the following
conditions

Condition 1
Using GDS2 monitor Engine Evap Data
Look at the Purge Valve when the concern is present
If the condition is present when the Purge Valve is active inspect the EVAP Cannister for evidence of fuel
intrusion, by removing the cannister and checking for evidence of liquid fuel, or compare the weight of the
suspect cannister with a like vehicle or a new component
A saturated cannister will weigh significantly more than one that has not been compromised
There have been instances of the customer overfilling the fuel tank and filling the EVAP cannister with fuel
When this happens it allows fuel to be ingested by the engine causing this concern if this is found replace
the EVAP Cannister and re-evaluate the concern

Condition 2
There have been instances of the Engine Wiring Harness being shorted on the Fuel Injector circuits
When this happens it can cause an intermittent surge or shudder feel
This can happen WITHOUT setting injector control circuit DTC'S
The short may only happen momentarily and not set an injector concern
If the concern has not been isolated with the above conditions please refer to Bulletin 21-NA-149 for wire
harness chaffing on the Full Size trucks
On the Colorado/Canyon, inspect the harness near the turbocharger bracket, along the back of the cylinder
head, and any pinch points
Note: Often the conduit and the Woven Polyester Electrical Tape (PET) will not show evidence of damage
around pinch points, however upon opening the harness in a suspected area wire chaffing may be present
Condition 3
If none of the above are seen, verify the crankcase pressure using a water Manometer or the gauge on the
GE-41413 can be used
It should read -6 to -8 inH2O at a warm curb idle, on snap throttle it should not be positive or more
negative than -12 inH2O
If excessive crankcase vacuum or pressure is seen, or there is evidence of oil consumption inspect for a
damaged fine oil separator for damaged internal valves or the valves not fully seating.
The Fine Oil Separator is located on the back of the cylinder head NOT the camshaft carrier please refer to
the pictures below

If a damaged fine oil separator is found verify there is not a mechanical concern with the engine
If no mechanical concern exists then replace the fine oil seperator and re-evaluate

If none of the above concerns are found or P064D is set please replace the HO2S Sensor 1 (Pre-Catalyst)
sensor and re-evaluate the concern

Warranty Information
For vehicles repaired under the Powertrain coverage, use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle History (IVH) for coverage information.
Labor Operation

Description

Labor Time

8481098

Roadtest and Diagnostic Testing

0.8 Hr.

*This is a unique Labor Operation for Bulletin use only.

Version History

Version

1

Modified

05/12/2025 - Created on.

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