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Service bulletin 20NA174

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10180694
Published by NHTSA2020-10-05
Manufacturer's number20NA174
Manufacturer's date2020-08-28
NHTSA componentEXTERIOR LIGHTING; ELECTRICAL SYSTEM

NHTSA's summary

This technical bulletin provides repair information to correct a customer concern of Malfunction Indicator Lamp (MIL) Illuminated With DTC P037C.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system, Lighting

Trouble codes named

P037C

Vehicles listed
CADILLAC CT42020

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
20240602024-02-01. Lights And Instruments
20227002022-12-08. Lights And Instruments
22V9030002022-12-08. EXTERIOR LIGHTING:LIGHTING CONTROL MODULE:SOFTWARE

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
24-NA-2292025-06-03. Service bulletin. 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-0872025-05-02. Service bulletin. 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.
13-08-116-001K2025-04-25. Service bulletin. 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-0982025-04-24. Service bulletin. 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.
15-06-03-001F2025-04-15. Service bulletin. 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.
22-NA-0942025-03-12. Service bulletin. This service bulletin provides repair information to correct a customer concern of a loss of cabin heat.
23-NA-0642025-02-12. Service bulletin. This service bulletin provides information on the Transport Mode Feature, also known as Logistics mode, which is used to increase the 12V Battery stand time of the vehicle during transit and or long period of stand time at the dealerships.
21-NA-0432025-02-12. Service bulletin. This bulletin advises the dealers to maintain the vehicle stock on hand by doing a full inspection on the vehicles before being sold (prepping) to the customer.
21-NA-1352025-02-12. Service bulletin. This service bulletin provides information to inform dealership personnel about Law Enforcement and Government vehicles that request to disable or enable content.
01-08-42-001Q2025-02-11. Service bulletin. This service bulletin provides information on Exterior Lamp Condensation and Water Leak Information and Replacement Guidelines.