Well, I've been datalogging now for a while using Datamaster. I always log the engine specs.

Today I was messing with some of the "switches" - you know, the boxes in the upper-right-hand corner... ..."left o2 ready" "right o2 ready" "closed loop" "fan 1 relay" "fan 2 relay" etc...

So I toggled one of them to look at "Trans MALF" by accident. Didn't even realize I had done so until it popped up as "ON." WTF?? I thought the PCM didn't really read the T56 tranny. Apparently not...

So I switched over to log the transmission data. As soon as I start rolling, I get a DTC code. I hover over the box and realize it's a DTC #91 - "1-4, 2-5 Shift Light Fault." So I think back, and realize that there's a way to toggle off the "shift light fault" within TunerCat. I do this and reload the program into my PCM. The DTC code goes away.

Which gets me to thinking... Did that DTC affect the way my car runs at low RPM's???? I was having major stumbling issues at low RPM's when my engine went into closed loop. I never saw any DTC's (on the engine side of things) so I figured it wasn't that type of issue. I had never checked the tranny!!!


DO TRANSMISSION CODES AFFECT THE WAY YOUR ENGINE OPERATES??