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Service bulletin T-TT-0556-19

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 id10164872
Published by NHTSA2019-09-16
Manufacturer's numberT-TT-0556-19
Manufacturer's date2019-08-02
NHTSA componentELECTRICAL SYSTEM:12V/24V/48V BATTERY

NHTSA's summary

TT: When testing the battery during PDS with either the DSS-5000 or DCA-8000 battery diagnostic tools, the battery tester may provide inaccurate results if it is connected to the remote battery posts under the hood.

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, 12-volt battery

Vehicles listed
TOYOTA SUPRA2020

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

Other bulletins for the same vehicles and component
T-TT-0687-222022-04-18. Service bulletin. TT: When customers have a concern about a discharged battery, no start, or general battery concern, the DCA-8000 is the only appropriate tool to use for diagnosis
T-TT-0553-19 Rev2020-08-24. Service bulletin. TT: The new DCA-8000 Diagnostic Charger may cause your facility?s Ground Fault Circuit Interrupter (GFCI) breaker to trip. A GFCI breaker can be tripped for various reasons, one of the reasons may be related to the DCA-8000. We are investigating this issue to determine the root cause. Other reasons the GFCI breaker may trip ?Circuit demand is too high for GFCI rating ?Worn out GFCI internal contacts ?Improper installation or wiring of GFCI breaker
T-SB-0050-192019-06-24. Service bulletin. TSB: Long-term or off-site storage requires special care to keep vehicles factory fresh and ready for delivery. The following guidelines should be performed to minimize vehicle component/part degradation due to extended vehicle storage conditions. Long-term storage can affect a vehicle?s systems and components. Any problems that are found should be corrected immediately.