Note: This transmission is equipped with an electronically controlled capacity clutch (ECCC), which allows
operation of the clutch without fully locking to the torque
converter cover. The clutch maintains a small amount
of slippage, approximately 20 RPM, in 2nd, 3rd, 4th,
5th, and 6th gears, depending on the vehicle application. ECCC was developed to reduce the possibility
of noise, vibration or chuggle caused by TCC apply.
Full lockup is available at highway speeds on some
applications.
7. Part Throttle Step-in Downshifts:
⇒

Place the gear selector in the DRIVE position.

⇒

Accelerate the vehicle at light throttle (5-10
percent) until 3rd gear is just achieved.

⇒

Quickly increase throttle angle until
commanded gear indicates that a downshift to
2nd gear is commanded.

⇒

Verify that the transmission downshifts within
2 seconds of the throttle movement

⇒

Repeat steps 2 to 4 at higher speed to achieve
4th gear and then step in to command a 4th
gear to 3rd gear downshift.

⇒

Repeat steps 2 to 4 at higher speed to achieve
5th gear and then step in to command a 5th to
4th gear downshift.

2. Accelerate the vehicle using a steady throttle
position between 15 and 20 percent. Hold the
throttle steady.

⇒

Repeat steps 2 to 4 at higher speed to achieve
6th gear and then step in to command a 6th
gear to 5th gear downshift.

3. As the transmission upshifts, there should be a
noticeable shift feel or engine speed change within
1 to 2 seconds of the commanded gear change.
The PC solenoid pressure command should
change to “YES” for the oncoming clutch and the
PC solenoid pressure command should change to
“NO” for the off going clutch.

⇒

Note any harsh, soft, or delayed shifts or
slipping. Note any noise or vibration.

• TCC Slip Speed
• TFP Switch 1
• TFP Switch 2
• TFP Switch 3
• TFP Switch 4
• PC Sol. 2 Pressure Cmd.
• PC Sol. 3 Pressure Cmd.
• PC Sol. 4 Pressure Cmd.
• PC Sol. 5 Pressure Cmd.
• Shift Solenoid 1 and 2
1. Place the gear selector in the DRIVE position.

4. Note any harsh, soft, or delayed shifts or slipping.
Note any noise or vibration.
5. The torque converter clutch (TCC) feel may not be
noticeable. In many applications the TCC will apply
after the 1-2 shift and TCC events will not be easily
detected using engine speed. Monitor TCC PC
solenoid pressure command while driving and
check TCC slip speed when the pressure
command indicates that the TCC is commanded to
apply.
6. When the TCC applies, slip speed should be
controlled to below 100 RPM when the transmission is not shifting, and the throttle is held
steady. If the TCC slip exceeds this value for more

8. Coasting Downshifts:
⇒

Place the gear selector in the DRIVE position.

⇒

Accelerate the vehicle to 6th gear with the TCC
applied.

⇒

Release the throttle and apply the brakes.

⇒

Verify that the downshifts occur as commanded
by monitoring gear ratio, which should change
after commanded gear changes.

⇒

Note any harsh, soft, or delayed shifts, or
slipping. Note any noise or vibration.

9. Reverse:
⇒

With the vehicle stopped, move the gear
selector to REVERSE.

⇒

Slowly accelerate the vehicle to a 10-15
percent throttle position.

⇒

Verify that there is no noticeable slip, noise, or
vibration.

Bulletin No.: 21-NA-169

May, 2024

10. Road Test Results:
⇒

Diagnostic TIP: If completion of the above tests
are inconclusive to isolate if the transmission
shifting concern(s) are internal transmission or
input/command, can use the control function
feature in GDS2 to command all shifts. If when
using GDS2 to command shifts and transmission shifts into each range commanded, the
concern is generally an input/command
concern, and not an internal transmission
concern. If ranges are not completed when
using GDS2 to command, then generally the
concern is an internal transmission concern
and not an input/command concern.

⇒

If noise or vibration concern is noted, follow
Noise and Vibration Analysis in SI using
Chassis Ears and PICO scope in diagnosis.

⇒

If upshifts and downshifts are harsh, soft,
delayed, or slip, follow SI diagnosis for
condition.

Step Five - DTC
If any of the following DTCs are current or reset during
the road test, record on the repair order, and follow the
instructions below for that DTC.
• P0796 Transmission Control Solenoid Valve 3
Stuck Off
• P0797 Transmission Control Solenoid Valve 3
Stuck On
• P2723 Transmission Control Solenoid Valve 5
Stuck Off
• P2724 Transmission Control Solenoid Valve 5
Stuck On
If any of the above first group of DTCs are current or
reset on the road test, the transmission must be
removed from the vehicle and inspected for damage to
the clutch plates. If hot spots or other evidence of a
slipping clutch, then follow SI procedure for
replacement of the affected clutch plates and replace
both the solenoid body and valve body.
• P0746 Transmission Control Solenoid Valve 1
Stuck Off
• P0747 Transmission Control Solenoid Valve 1
Stuck On
• P2731 Transmission Control Solenoid Valve 6
Performance
• P2732 Transmission Control Solenoid Valve 6
Stuck Off
• P2733 Transmission Control Solenoid Valve 6
Stuck On
• P2820 Transmission Control Solenoid Valve 9
Stuck Off

Page 5

• P2821 Transmission Control Solenoid Valve 9
Stuck On
• P18AA Transmission Range Control Valve 1
Position Switch Circuit Stuck On
• P18AB Transmission Range Control Valve 1
Position Switch Circuit Stuck Off
• P18AC Transmission Range Control Valve 2
Position Switch Circuit Stuck On
• P18AD Transmission Range Control Valve 2
Position Switch Circuit Stuck Off
• P18AE Transmission Range Control Enable Valve
Stuck Off
If any of the above second group of DTCs are current
or reset on the road test and the transmission fluid is
red, translucent, and doesn’t have a burnt odor, then
only replace both the solenoid body and valve body. If
the transmission fluid is very dark or black, not translucent, and has a burnt odor, then in addition to
replacing the solenoid body and valve body, the transmission should be removed from the vehicle and
inspected for damage to the clutch plates, if found
follow SI procedure to replace them.
• P0741 Torque Converter Clutch (TCC) System
Stuck Off
• P0776 Transmission Control Solenoid Valve 2
Stuck Off
• P0777 Transmission Control Solenoid Valve 2
Stuck On
• P2817 Transmission Control Solenoid Valve 8
Stuck Off
• P2818 Transmission Control Solenoid Valve 8
Stuck On
If any of the above third group of DTCs are current or
reset on the road test and the transmission fluid is red,
translucent, and doesn’t have a burnt odor, then only
replace the solenoid body. If the transmission fluid is
very dark or black, not translucent, and has a burnt
odor, then in addition to replacing the solenoid body,
the transmission should be removed from the vehicle
and inspected for damage to the clutch plates, if found
follow SI procedure to replace them.
• P2714 Transmission Control Solenoid Valve 4
Stuck Off
• P2715 Transmission Control Solenoid Valve 4
Stuck On
• P187D Transmission Park Valve Stuck On
• P187E Transmission Park Valve Stuck Off

Page 6

May, 2024

If any of the above fourth group of DTCs are current or
reset on the road test and the transmission fluid is red,
translucent, and doesn’t have a burnt odor, then only
replace the valve body. If the transmission fluid is very
dark or black, not translucent, and has a burnt odor,
then in addition to replacing the valve body, the transmission should be removed from the vehicle and
inspected for damage to the clutch plates. If found,
follow SI procedure to replace them.
• P18A8 Transmission Park Control Solenoid
Actuator Stuck Off
• P18E7 Transmission Park Valve Position Sensor 1
Performance
• P18E8 Transmission Park Valve Position Sensor 2
Performance
• P27EC Transmission Range Control Valve 1
Position Switch Performance
• P27F0 Transmission Range Control Valve 2
Position Switch Performance
Note: If P18A8 is set, then also replace the Park Inhibit
Solenoid Actuator along with the solenoid body and
valve body.
If any of the above fifth group of DTCs are current or
reset on the road test and the transmission fluid is red,
translucent, and doesn’t have a burnt odor, then check
vehicle battery health and state of charge per SI
instructions, also check battery, TCM, and Transmission ground for voltage loss. If battery and grounds
do not show problem and DTC is current, then replace
both the solenoid body and valve body. If the transmission fluid is very dark or black, not translucent, and
has a burnt odor, then in addition to replacing the
solenoid body and valve body, the transmission should
be removed from the vehicle and inspected for damage
to the clutch plates. If damage is found, follow SI
procedure to replace the clutch plates.

Bulletin No.: 21-NA-169

Symptoms other than listed above should be diagnosed
using SI procedures and repaired as necessary.

Parts Information
No parts are required for this repair.

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

Description

Labor Time
1.5 hrs

8486018*

Perform Fluid Level Check
and Evaluate Condition, Oil
Pressure Checks and
Service Fast Learn

8463690**

Control Valve Body
Replacement

8463700

Control Valve Solenoid
Body Replacement

Use Published Labor
Operation
Time

*This is a unique Labor Operation for bulletin use only.
This operation is only used if no other transmission components are replaced. Can only be used if the vehicle is
below 19,000 km (12,000 miles) on the odometer.
**If valve body and solenoid body are replaced at the
same time, use this Labor Operation.
Note: If transmission is removed from vehicle and internally inspected for clutch or hardware failure, use the appropriate valve body or solenoid body Labor Operation for the
DTC and include the clutch or hardware inspection and repair time as straight time to the labor operation.

If there are no current DTCs or they were/are only in
history and are not able to be reproduced, perform the
Transmission Service Fast Learn Procedure in SI and if
no DTCs reset, return the vehicle to the customer.
Version

7

Modified

Released July 20, 2021
Revised September 28, 2021 – Added the 2022 Model Year, updated information under
both Notes in step 5 under Step Four - Perform Road Test and updated information under
Step 5 - DTC.
Revised November 29, 2021 – Added Holden Equinox model, Europe, Australia/New
Zealand to Involved Region or Country section and updated the service publication reference in last arrow under Information.
Revised April 08, 2022 - Replaced PIP5697B with 21-NA-201 and PIT5778A with 21NA-122 in the Information section.
Revised August 04, 2022 - Removed Equinox and Regal from Models, removed 2020
from Model Year and Added 2021 to 2023 Model Year, and Deleted Reference to TSB
18-NA-359 from Information section.
Revised August 02, 2023 - Added 2024 Model Year to Applicable Models.
Revised May 03, 2024 - Added PIP5974 under Information section.

Bulletin No.: 21-NA-169

May, 2024

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.

Page 7

WE SUPPORT VOLUNTARY
TECHNICIAN
CERTIFICATION