So i have a 2000 blazer 4x4

i'll start at the beginning. Last year in my auto class in highschool we relocated some grounds down below the battery tray that were looking really bad.

i put them in a better spot and confirmed a good ground.

when i left class the transmission kicked in to limp mode and the speedometer pegged out at 100mph.

i pulled it back in and checked the grounds again and put it back together and the speedometer fixed back to 0. and the trans was out of limp mode.

i started driving again down the road and the transmission went back in to limp mode(2-3rd gear, reverse, with manual shift) but speedometer was reading correctly.

in the past when i was towing with the blazer and at 55 mph with a trailer the rpm would slightly rise then fall.

i could slightly hold the brakes and the rpm would increase but hold steady. i believe the torque converter was locking and unlocking but i had no codes and the transmission was not in limp mode.


Fast forward to almost a year now. the blazer has been sitting in the yard and i've been driving a different vehicle.

today i went out and jump started in. ran like crap then cleared up. it still has the transmission code.

i want to get it running right again because a little car doesn't do very good in the snow here.

i checked the fuse that controls the transmission shift interlock in the engine compartment and that was good.

there is no other stored codes beside an ABS code that i have had for awhile.

i changed the tranny fluid and filter shortly before this happened also.

i'm thinking shift solenoid.

also is the torque converter lock up solenoid the same as the shift solenoids? i believe advance auto part # call for the same

what is your guy's input? it's freezing here and 4wd would be nice.

thanks guys.

 

https://blazerforum.com/forum/diagno...plained-28393/

Hope this helps

 

that helps some. i don't have a scan tool that sophisticated though to turn solenoids on and off.

it leaves alot of possibilities too. i guess i'll start by replacing that shift solenoid and lock up solenoid and check to see if i disturbed any wiring when i did the fluild and filter. maybe the wiring is damaged too.

sounds like the vcm could be messed up too and grounding properly...

 

I threw that code a while ago (at least i think it was the same one) and I just replaced both solenoids (A and B) and it went away, but I'd give all the wiring a check.

 

allright i appreciate the information.

i towed a frequent amount with this blazer too before it went down and it always seemed to hold OD pretty well until that torque converter issues but i'll see if i can replace that solenoid too.

 

well i picked up a tcc solenoid and 2-3rd shift solenoids today at advance. hopefully putting them in tomorrow.

 

i have the pan off and i replaced the solenoid.

i have to go get a gasket forgot that

i tested continuity through the old solenoid and it has continuity. reading about 6 ohms at 28 degrees.

is there anything else i can test while i have the pan off with just a multimeter?

i don't have access to all the fancy jumper harnesses they call for testing.

can i test the old solenoid by taking voltage to it? is it polarity sensitive on the pins? or can i just test it one way and then the other without damaging it?

how about the wiring harness in the pan?

thanks

 

I'd test for continuity on the harness in the pan, and check for broken connectors or clips on them while in there.

I'm not sure if they're polarity sensitive or not.

 

well good news and bad.

the shift solenoid fixed the limp mode. so i have all gears now. bad news is i don't have tcc lockup.

it trys then just falls on its face and downshifts to 3rd

i did some research and it looks like the 700r4 uses the same tcc solenoid but they don't look the same on the inside to me.

i talked to one of my teachers today that worked at a gm dealership and he said he saw alot of lazy tcc solenoids in the 4l60e.

he also told me it could be the pulse width modulation solenoid too

i guess when i get back home i'll check the brake switch too because that can effect lock up too. i go out of state for school during the week..

feels good to finally drive it down the road after sitting for so long.

rear brakes feel like they are locking up too which could be part of the problem too.

 

well....

i replaced the tcc solenoid and the pulse width modulation solenoid today..

the old tcc solenoid was cracked in 2.

i test drove it and it seems to lock but at exactly 55mph there is a

1600rpm to 1700 rpm jump back and forth at a constant rate.

at 60mph it holds rpm steady.

i still need to check the brake switch...

i know when i lightly hold the brakes the rpm jump to 1900 and hold steady.

wondering if its a fuel injection issue now