First of all this has been a huge pita. Here's the deal, the check engine light is on and does not show any codes present as of now. BUT before it had a p0102 showing up. So I looked over everything and first I found a broken ground wire. Fixed that and the light shut off. I drove down the road and the eng-1 fuse blew and the light came back on with the same code and has not gone off since. So it over again and found that one of the rear o2s had rubbed up against the heat shield an destroyed it pretty much. So I replaced the o2 and cut out the heat shield so I would not rub any more. The eng-1 fuse has not blown but the light is still on and there are no codes showing up. Another thing is that the 1 to 2 shift bangs hard once it is warmed up every once and a while. I replaced the valve body and it is still doing the same thing. Any information to fix this problem would be greatly appreciated.

 

p102 is a maf sensor code so focus on the maf until you have reason to focus elsewhere.

 

I agreed not to criticise the 4L60-E's design flaws anymore on this forum but I can give you some advice about the earlier model ones.

1996 model PCMs had an internal grounding bridge problem that if present could cause erratic line pressure in the transmission. there was a kit created to address the problem, GM part number 12167310. I'm not sure of that part number is even still valid, it's old. The repair kit just has you move a few wares around between the different PCM connectors and includes the jumper needed to do it cleanly.

This internal PCM ground issue could be the source of your SES light.

 

Well in reply to the first post, I took a whole breather assembly with maf sensor and still the same code. It had to be a wiring issue some where. Which it appears to have fixed the code, but the ses light is still on.

The thing is, the only reason that I even looked into the problem was the transmission starting shifting real hard from the 1 to 2 shift and hard from 2 to 3 shift. Then I found the body to frame ground broken and the o2 sensor messed up. This has cleared the code but the ses light is on. I will try and find that part you mentioned.

 

hmmm so it fixed the hard shifting ok thats good, that means the maf issue is probably taken care of...because usually, well on some vehicles, when the maf fails the computer commands max line pressure, which is why you were having harsh shifts when the code popped.

have you tried just clearing the code?

Does it still come back as a p0102 or is there a different code thats actually triggering the ses light to come on?

 

Well the hard shifting has not gone away. I ordered the kit mentioned earlier and installed it. The ses light stayed off for a while and has come back on, and its the same code, p0102.

The transmission has a very hard 1 to 2 shift, once it is warmed up. Is there some way that a wire from the MAF sensor is grounding out and causing the light and the transmission to shift hard? I'm pretty much stumped here.