TSB's

Module Damage Caution

This bulletin applies to an array of GM vehicles, including 2013-2019 Cadillac ATS, 2017-2019 CT6, 2008-2019 CTS, 2015-2019 Escalade, 2008-2016 SRX, 2008-2011 STS and 2019 XT4; 2016-2019 Buick Cascada, 2009-2019 Enclave, 2016-2019 Envision, 2010-2019 LaCrosse, 2011-2019 Regal and 2012-2017 Verano; 2009-2010 Saturn Outlook, 2007-2010 Saturn Sky; 2007-2010 Pontiac Solstice, and a lengthy number of Chevy and GMC vehicles in the same year ranges.

The bulletin discusses module damage from incorrect AFIT usage on vehicles equipped with direct fuel injection. After connecting the AFIT (active fuel injector tester) to the vehicle’s ECM connectors, the engine may begin to turn over, and then exhibit a no-crank condition afterwards. It may also be found on vehicles equipped with an automatic transmission that there is no communication with the transmission control module (TCM).

This issue can occur when the AFIT SIDI testing cables (cables for testing direct injected fuel injectors) are plugged directly into the AFIT MCU (main control unit) with the MCU powered up. On vehicles with automatic transmissions, this can cause internal damage to the TCM, preventing the engine from cranking and the TCM/TEHCM from communicating.

The TCM will require replacement to remedy the no-crank/no-start condition. The AFIT SIDI (spark ignition direct injection) testing cables were intended to plug into the DMU (drive & measurement unit), not the MCU (main control unit). GM dealers were sent an update kit to prevent the MCU’s power supply from being connected if SIDI testing cables were connected directly to the MCU.

The kit contains guards/adapters that are permanently attached to the end of the SIDI testing cables with adhesive.
<p>The kit contains guards/adapters that are permanently attached to the end of the SIDI testing cables with adhesive.</p>

The adapter/guard is installed in this example on the end of the SIDI cable.
<p>The adapter/guard is installed in this example on the end of the SIDI cable.</p>

With the adapter/guard properly installed, it will cover the power plug port on the MCU if the SIDI cable is mistakenly plugged into the MCU.
<p>With the adapter/guard properly installed, it will cover the power plug port on the MCU if the SIDI cable is mistakenly plugged into the MCU.</p>

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