# Service bulletin 20NA178

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: 10181705
- Published by NHTSA: 2020\-10\-26
- Manufacturer's number: 20NA178
- Manufacturer's date: 2020\-09\-09
- NHTSA component: STEERING; ELECTRICAL SYSTEM

## NHTSA's summary

This technical bulletin provides repair information to correct a customer concern of Service Driver Assist and/or Take Steering Messages on Start\-up, Advanced Driver Assist Systems \(ADAS\) Features Not Available.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181705-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181705-9999.pdf)

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

## Components

Electrical system, Steering

## Vehicles listed

- 2020 to 2021 CADILLAC CT4
- 2020 to 2021 CADILLAC CT5
- 2021 CHEVROLET SUBURBAN
- 2021 CHEVROLET TAHOE
- 2021 GMC YUKON
- 2021 GMC YUKON XL

## Recalls for the same vehicles and component

- [2021380](/recalls/tc/2021380.md), 2021-06-17: Steering
- [21V455000](/recalls/nhtsa/21V455000.md), 2021-06-17: STEERING:STEERING CONTROL MODULE
- [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.
- [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.
- [21\-NA\-166](/bulletins/11019325.md), 2025-06-06, Service bulletin: EXTERIOR LIGHTING; STEERING. This informational bulletin provides information on the turn signal stalk not cancelling and/or mis cancelling.
- [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.
- [25\-NA\-065](/bulletins/11017173.md), 2025-04-24, Service bulletin: STEERING; SERVICE BRAKES; FUEL/PROPULSION SYSTEM. This informational bulletin instructs the tech when fuel/fluid is needed to be tested and where it can be sent for analysis.
- [15\-06\-03\-001F](/bulletins/11017031.md), 2025-04-15, Service bulletin: ELECTRICAL SYSTEM. This service bulletin provides information to diagnose batteries that have set for a long period of time and/or cold weather climates and testing those batteries.

JSON: [/v1/bulletins/10181705](/v1/bulletins/10181705)

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