# Service bulletin 20NA189

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 10181714
- Published by NHTSA: 2020\-10\-26
- Manufacturer's number: 20NA189
- Manufacturer's date: 2020\-09\-17
- NHTSA component: POWER TRAIN; ELECTRICAL SYSTEM

## NHTSA's summary

This technical bulletin provides repair information to correct a customer concern of Transmission Control Module Offline Event.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181714-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181714-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Electrical system, Transmission and driveline

## Vehicles listed

- 2021 CHEVROLET SUBURBAN
- 2021 CHEVROLET TAHOE
- 2021 GMC YUKON
- 2021 GMC YUKON XL

## Recalls for the same vehicles and component

- [2024637](/recalls/tc/2024637.md), 2024-10-24: Powertrain
- [24V797000](/recalls/nhtsa/24V797000.md), 2024-10-24: POWER TRAIN:AUTOMATIC TRANSMISSION:FLUID/LUBRICANT:VALVES/VALVE BODY; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE
- [2022027](/recalls/tc/2022027.md), 2022-01-27: Powertrain
- [22V036000](/recalls/nhtsa/22V036000.md), 2022-01-27: POWER TRAIN:DRIVELINE:DRIVESHAFT
- [21V421000](/recalls/nhtsa/21V421000.md), 2021-06-10: AIR BAGS:SRS MALFUNCTION WARNING LAMP/LIGHT; ELECTRICAL SYSTEM:SOFTWARE

## Other bulletins for the same vehicles and component

- [23\-NA\-170](/bulletins/11024486.md), 2025-10-25, Service bulletin: ELECTRICAL SYSTEM; ENGINE. This bulletin advises the tech to inspect deeper into what may be to main cause of an engine failure.
- [N242454441 \-03](/bulletins/11024189.md), 2025-10-09, Service campaign: POWER TRAIN. Certain vehicles listed above, may have a condition where the transmission control valve has worn, resulting in a gradual loss of pressure within the valve. The effects can cause harsh shifting, setting a service engine soon message, reduced engine performance or P0747 diagnostic trouble code. Dealers are to install a new control valve body. The repairs will be made at no charge to the customer.
- [22\-NA\-182](/bulletins/11023369.md), 2025-09-27, Service bulletin: POWER TRAIN. This service bulletin advises the technician to check if the transmission cooler lines are twisted to correct customer concerns of Harsh Shift, Shudder, Surge, Stall, Transmission Overheating and/or High Transmission Fluid Temperature.
- [N252494003\-01](/bulletins/11019752.md), 2025-06-26, Service campaign: POWER TRAIN. Certain vehicles listed above, may have a condition where the connecting rod and/or crankshaft engine components in these vehicles may have manufacturing defects that can lead to engine damage and engine failure. This special coverage covers if an engine failure occurs in the vehicle as a result of the condition described above for a period of 10 years or 150,000 miles \(240,000 km\), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership. For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after May 23, 2025, are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to May 23, 2025, must be submitted to the Service Contract provider. Vehicle owners or lessees who paid for repairs referenced in this Special Coverage \(“Customers”\) are eligible for reimbursement of their reasonable and customary expenses in accordance with the procedures specified below. The conditional right to reimbursement is provided by GM solely in the interest of customer satisfaction and is personal to Customers. Customers may not assign and GM does not consent to any assignment of any Customer’s right to submit reimbursement claims, or to receive reimbursement, or any other rights granted by this Special Coverage to any third party, including but not limited to service contract providers, and this Special Coverage is not intended to and does not confer any third party beneficiary, subrogation or contribution rights, or any other rights to reimbursement, against GM, whether in law, equity or otherwise, on any third parties. Dealers are to replace the engine. The repairs will be made at no charge to the customer.
- [PI0281L](/bulletins/11019516.md), 2025-06-12, Service bulletin: STEERING; POWER TRAIN; SUSPENSION. This preliminary informational \(PI\) bulletin provides information to dealership personnel that may be helpful when addressing underbody component corrosion with customers.
- [24\-NA\-229](/bulletins/11019017.md), 2025-06-03, Service bulletin: ELECTRICAL SYSTEM. This bulletin provides a procedure on how to check for a battery drain utilizing the Picoscope and how to measure the load on the system that may be causing a drain.
- [25\-NA\-087](/bulletins/11017595.md), 2025-05-02, Service bulletin: ELECTRICAL SYSTEM. This service bulletin provides information on the proper Reflective High Temperature Heat and/or Insulating Tape to use for certain repairs, such as Wiring Harness Repairs.
- [23\-NA\-185](/bulletins/11017255.md), 2025-04-28, Service bulletin: POWER TRAIN; ELECTRICAL SYSTEM; STEERING. This service bulletin helps diagnose/reduce possible CCND issues on Transfer Cases \- Service 4WD on DIC, Intermittent Failures, Noise Concerns, Driveline/Steering Vibration/Shudder, Intermittent DTCs/MIL Illuminated, Engagement/Disengagement/Ratcheting Concerns.
- [13\-08\-116\-001K](/bulletins/11017244.md), 2025-04-25, Service bulletin: ELECTRICAL SYSTEM. The intent of this service bulletin is to identify aftermarket ALDL or DLC interface devices as potential sources for causing multiple customer concerns that do not have other diagnostic methods to identify them.
- [24\-NA\-098](/bulletins/11017207.md), 2025-04-24, Service bulletin: ELECTRICAL SYSTEM; UNKNOWN OR OTHER. This service bulletin provides information for dealers/technicians on Service Programming System \(SPS\) Error Codes E4398, E4399, E4401, E4403, M4404, M4413, M6954, M6955, E4414, E4423, E4491, E4492, or E6961 and resolution information.

JSON: [/v1/bulletins/10181714](/v1/bulletins/10181714)

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