Does your stalled auto unlock when coasting?
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From: Lake Tapps, WA
Frost was the guy that tipped me off to how the pcm looks at the brake pedal switch. I'm glad I got that fixed it was waking me up at night, I knew it was pcm related but couldn't figure out what it was seeing or not seeing to unlock the convertor.
I just want to add this is only for the 4L60E, my understanding is the 4L80E is designed to disengage the lock up clutch when coasting.
I just want to add this is only for the 4L60E, my understanding is the 4L80E is designed to disengage the lock up clutch when coasting.
My Silverado with a 4L80E unlocks at 0% TPS and it is annoying.
What I'm trying to figure out is how you got so many replies and you never said what kind of vehicle this was and no one even asked.
Thread Starter
10 Second Club
iTrader: (27)
Joined: Sep 2008
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From: Lake Tapps, WA
I want to add a comment so if some has a problem in the future and does a search, I quick test to see if the brake circuit is working. With the convertor locked put your foot on the brake normal operation it will release the lock up clutch. If the clutch stays locked it's in the brake switch circiut.
Don't get this confused with the brake light switch, it's a seperate switch on the pedal arm, the tcc brake switch is plastic and is adjusted by ratcheting it up or down in the holder no tools required. The power for the circuit comes from the eng sensor fuse (fuse box is in eng compartment) when I pulled the fuse the car still ran and didn't throw any codes.
On the pcm for a 99 F body its pin no.33 ppl wire might be the same for other years, verify that with key on you see 12v, if you step on the brake pedal it will drop to 0v, this is proper operation of the switch and circuit.
Power to the switch is a pink wire from the eng sensor fuse, when you look at the switch it will be the pink wire that sits directly across from the ppl wire, the reason I added that is there are 2 pink wires in the 6 wire plug. It should see power anytime the key is on.
Don't get this confused with the brake light switch, it's a seperate switch on the pedal arm, the tcc brake switch is plastic and is adjusted by ratcheting it up or down in the holder no tools required. The power for the circuit comes from the eng sensor fuse (fuse box is in eng compartment) when I pulled the fuse the car still ran and didn't throw any codes.
On the pcm for a 99 F body its pin no.33 ppl wire might be the same for other years, verify that with key on you see 12v, if you step on the brake pedal it will drop to 0v, this is proper operation of the switch and circuit.
Power to the switch is a pink wire from the eng sensor fuse, when you look at the switch it will be the pink wire that sits directly across from the ppl wire, the reason I added that is there are 2 pink wires in the 6 wire plug. It should see power anytime the key is on.
wanted to bump this up because i just installed a converter and its doing the same thing. Never unlocked with the stock stall when i let off the throttle (until i touched the brake)so im wondering if it would still be the brake switch...? or is the stock stall so tight that the pwm makes it feel like its still fully locked? either way how do i disable pwm with hp tuners?
thanks
thanks
i suspect with a higher stall its way more noticable locking/unlocking than a stock stall, but i also guess with a higher stall in a stock style computer it now has a diff throttle opening to look at, so prob a retune would change things
ok so i must have the same problem as the OP. I went out driving tonight and the converter will only lock above ~10% tps and over 40 mph unlocks at 35, even though i told it to lock at 25mph in 3rd... I logged everything and the pcm is commanding the converter to unlock when i let off the throttle. Converter doesnt unlock when i touch the brake (still on the throttle). After i figured out this was the problem BOOM brake light and abs inop light pop on. Check the codes and sure enough it has brake switch pending. lol... weird how this just happened after a torque converter install. I wonder if pressing the brake all the way to the floor would cause this? Because when i went to the track on the stock stall i was pushing the pedal to the floor to keep from pushing through the brakes... and i never had this problem before. I distinctly remember the stock converter unlocking and then locking on the highway when i just touched the brakes. I also tuned out the pwm and the clutch locks up much harder now.
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mine unlocks when I lift above a certain percentage throttle, but I'm also getting a TCC code and think its damaged because if I hold the throttle to keep it locked and hit the brake too it doesn't unlock
Thanks for the engine sens tip. Turns out that fuse was blown because the o2 wire shorted out against the header and blew that fuse. My stall is working just as it should now!! makes me so much happier. God thats annoying, the stall unlocking and then relocking every time you let off of the gas. Now it stays locked as commanded by the pcm in my tune. I knew i should have never installed those stupid stock o2 wire's. I mean im running open loop speed density they're just there as exhaust plugs... haha.
Mine is doing this but won't lock back up. you can feel it trying to but out won't lock hard and stay that way unless I hit the brakes. It feels like it is in neutral almost. if I floor it while its doing this it just flashes the hell out of the converter.
