Bulletin No.: PIP6036B
Published date: 05/8/2025

Preliminary Information
PIP6036B Diagnostic Aids For CVT transmissions With A Surge Or
Fishbite Sensation
Models
Brand:

Model: Model Years:

Buick
Encore GX 2022 - 2025
Chevrolet Equinox
2025
Chevrolet Malibu
2022 - 2025
Chevrolet Trailblazer 2022 - 2025
GMC
Terrain
2025

VIN:
Engine: Transmissions:
from to
All
All All
MRG
All
All All
MRQ
All
All All
MRG
All
All All
MRG
All
All All
MRQ

Involved Region or
Country

North America

Condition

Shudder/Fishbite feel under load.

Cause

Incorrect values learned in shift adapts.

Correction:
Some Customers may comment on a Shudder, Surge or Fishbite feeling.
This concern may have worsened over time.
This concern can feel like a single cylinder misfire, and is most often felt under load and
partial throttle between 1500 - 3000 RPM.
If this concern is found and there is no evidence of a misfire or Torque Converter Clutch
(TCC) concern it is likely caused by incorrectly learned transmission pressure adapts.
Note: A TCC Shudder is highly unlikely on this transmission due to how we control this
torque converter.
To Correct this concern, using GDS2 reset the transmission pressure adapts and perform
the following drive cycle to learn the transmission

CVT Learn Drive Cycle
Cold Garage Shifts
Start the vehicle cold and perform the following Garage Shift Procedure with
approximately 1-second pause in each state:
Park to Drive, Drive to Park
Park to Reverse, Reverse to Park
Park to Drive, Drive to Reverse, Reverse to Drive, Drive to Park

Warm-Up / Garage Shifts
Drive the vehicle normally for 5-10 minutes, then stop and perform the Garage Shift
Procedure. Repeat normal driving for another 5-10 minutes and perform the Garage Shift
Procedure again until the vehicle reaches regular operating temperature.
Note: Clutch slip learns will not complete if the transmission fluid temperature is too low .
Steady-State Driving
Once warmed up, drive the vehicle at the following steady-state speeds for approximately
5-10 minutes each. If learn bumps are felt, you can proceed to the next speed once the
bumps stop (do not use cruise control; just hold a constant pedal around the target
speed):
~30 miles per hour: Note how many bumps were felt and/or how long it took for the bumps
to stop.
~40 miles per hour: Note how many bumps were felt and/or how long it took for the bumps
to stop.
~55 miles per hour: Note how many bumps were felt and/or how long it took for the bumps
to stop.
Garage Shifts / ECM/TCM Sleep
After completing all three speeds, park the vehicle and perform the Garage Shift
Procedure, then shut the vehicle down and allow the ECM/TCM to go to sleep.
Turn the key off, open and close the driver’s door, and wait for the dome and dash lights to
go out (approximately 3-5 minutes). This sleep procedure allows the clutch slip learns from
this drive cycle to be stored in permanent memory.
Repeat
After the vehicle has gone to sleep, open the driver’s door, start the vehicle, and repeat
steps 2 and 3 two more times. This will result in a total of three learn cycles at the three
speeds, with ECM/TCM sleep in between.
Note: Step 2 may not be necessary to repeat if the vehicle is still at normal operating
temperature.
Final Check
Test drive the vehicle, performing garage shifts and steady-state driving to confirm the
issue(s) have been resolved.
Document and communicate findings from the final check.

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

* 8486528

Transmission Characterization

0.8 hrs

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

Version History

Version

3

Modified

01/08/2025 - Created on.
04/02/2025 - Updated to add Labor Operation
05/08/2025 - Updated to include Drive Cycle, Labor Time
and add new models

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