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nobox351y · 11-11-2018, 07:14 PM

2001 5.3 with a pre case mounted neutral safety switch 4l80e 93ish swapped into a 87 r20 burb.

Took it out for the first real test drive today and all seems to function well with the exception of the this code p0742.

It seems like the converter is failing to unlock under decel. As you come to a stop the transmission pulls the engine down to about 400 rpm and then it unlocks. It threw the code and after that the converter wouldnt lock up, which is fine until I get it figured out.

Aside from checking to make sure that the tcc circuit to the brake switch has 12 volts when brakes are not applied and 0 volts when they are applied, are there any other options?

I believe I have it wired correctly but will double check that for sure.

Thanks Guys

11-11-2018, 07:14 PM	#1
nobox351y Registered User Join Date: May 2016 Location: LeRoy Posts: 69	4l80e p0742 Code issue 2001 5.3 with a pre case mounted neutral safety switch 4l80e 93ish swapped into a 87 r20 burb. Took it out for the first real test drive today and all seems to function well with the exception of the this code p0742. It seems like the converter is failing to unlock under decel. As you come to a stop the transmission pulls the engine down to about 400 rpm and then it unlocks. It threw the code and after that the converter wouldnt lock up, which is fine until I get it figured out. Aside from checking to make sure that the tcc circuit to the brake switch has 12 volts when brakes are not applied and 0 volts when they are applied, are there any other options? I believe I have it wired correctly but will double check that for sure. Thanks Guys Last edited by nobox351y; 11-11-2018 at 08:21 PM.