# Service bulletin 20NA191

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: 10181716
- Published by NHTSA: 2020\-10\-26
- Manufacturer's number: 20NA191
- Manufacturer's date: 2020\-09\-17
- NHTSA component: ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING

## NHTSA's summary

This technical bulletin provides repair information to correct a customer concern of Auto Start/Stop Disabled with Malfunction Indicator Lamp \(MIL\) Illuminated and DTC U0599 set.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181716-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181716-9999.pdf)

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

## Components

Electrical system, Engine

## Trouble codes named

U0599

## Vehicles listed

- 2020 CADILLAC CT4
- 2020 CADILLAC CT5

## Other bulletins for the same vehicles and component

- [00\-06\-01\-026R](/bulletins/11026017.md), 2025-12-03, Service bulletin: ENGINE. This service bulletin provides information on replacing the intake manifold when the engine is replaced after severe internal engine damage.
- [23\-NA\-153](/bulletins/11024485.md), 2025-10-25, Service bulletin: ENGINE. The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is opened rapidly and advises the customer that it is normal for the delay.
- [15\-NA\-010](/bulletins/11020254.md), 2025-07-07, Service bulletin: ENGINE. This service bulletin provides information to dealership personnel for new vehicles with less than 1,000 miles that may not pass California smog inspection or smog inspection in other states.
- [25\-NA\-037](/bulletins/11019748.md), 2025-06-26, Service bulletin: ENGINE. This bulletin advises the tech that the Exhaust Roller Follower may be the issue with the engine Ticking noise, misfire or rough run and what to replace if found the cause.
- [21\-NA\-240](/bulletins/11019543.md), 2025-06-16, Service bulletin: ENGINE. This service bulletin provides diagnostic repair information to correct an oil leak in the engine.
- [25\-NA\-100](/bulletins/11019503.md), 2025-06-12, Service bulletin: ENGINE. This warranty administration bulletin provides policy information on vehicles outside of a California Emissions State who move to and register their vehicle in a California Emission State may be entitled to the 7 year, 70,000\-mile Emission Select State Component Limited Warranty.
- [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.
- [25\-NA\-076](/bulletins/11017302.md), 2025-04-29, Service bulletin: ENGINE. This informational bulletin advises the technician that the gasket for the timing chain tensioner is not required.
- [25\-NA\-052](/bulletins/11017263.md), 2025-04-28, Service bulletin: ENGINE. This bulletin advises the technician to flush the cooling system multiple times if oil has been found in the cooling system and replace the parts that may be contaminated due to oil in system.

JSON: [/v1/bulletins/10181716](/v1/bulletins/10181716)

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