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2020 - 2021 Corvette: Service Bulletin: #20-NA-123: Malfunction Indicator Lamp (MIL) Illuminated, DTCs U1961, U1983 Set - (Mar 8, 2021)

#20-NA-123: Malfunction Indicator Lamp (MIL) Illuminated, DTCs U1961, U1983 Set - (Mar 8, 2021)

Subject Malfunction Indicator Lamp (MIL) Illuminated, DTCs U1961, U1983 Set

Brand:

Model:

Model Year:

Breakpoint:

Engine:

Transmission:

from

to

from

to

Buick

Envision

2021

2021

Cadillac

CT4

2020

CT5

Escalade Models

2021

Chevrolet

Corvette

2020

Suburban

2021

Tahoe

GMC

Yukon Models

 

Involved Region or Country

North America, Middle East, GM Korea Company, Israel, Palestine

Condition

Some customers may comment that the Malfunction Indicator Lamp (MIL) is illuminated.

Technicians may find the following DTCs set:

  • U1961 - Control Module Security Hardware Internal Malfunction
  • U1983 - Serial Data Gateway Module Security Hardware Internal Malfunction

Cause

This condition may be caused by not clearing the DTCs and also allowing a sleep cycle after programming or serial data authentication configuration.

Correction

Clear the DTCs and allow the vehicle to go into sleep mode.

 

Version

3

Modified

Released June 02, 2020

November 13, 2020 – Added the Cadillac Escalade Models, Chevrolet Suburban, Tahoe and GMC Yukon Models and Warranty Information.

March 08, 2021 – Added the 2021 Buick Envision and 2021 MY to CT4, CT5 and Corvette.

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