Torque Converter Lock Up Not Working

[PSDGuy]

Hey All,

I have a 2000 7.3 with 4r100.

As the title says, my TCC is not working. I recently got an AE scanner - I have the following trouble codes for the switch test:

1536 - Parking brake applied fail
0220 - Throttle switch B circuit malfunction
1780 - TCS circuit of out self-test range
0571 - Brake switch A circuit malfunction
0703 - Brake switch B circuit malfunction
0565 - Cruise "On" signal malfunction
0566 - Cruise "Off" signal malfunction
0567 - Cruise "Resume" signal malfunction
0568 - Cruise "Set" signal malfunction
0569 - Cruise "Coast" signal malfunction

I also had a couple DTCs set in the PCM's memory and in the KOEO test relating to the EBP sensor failing (0470 and 0478 I believe).

I recently replaced the brake pedal switch (it is working according to the live AE monitor) and cruise control seemed to work okay the last time I used it (but I don't use it much).

Monitoring the sensors as I drive, the PCM was sending the lock signal to the trans (up to 100% PWM).

It appears to me that the TCC solenoid is not doing its job, but I'm not sure and don't really want to spend the time and $$ replacing a part that wasn't needed.

I'd like to get this fixed before Friday so I can tow my trail rig about 200 miles and not burn up lots of extra fuel unnecessarily.

Anyone have any input?


A little more info:

The TCC was not working when i bought the truck a few months ago.

The cab brake light was out, but I changed it a week ago - didn't help the problem.

The trans is supposedly "built", but I don't know the details of the build (it definitely has an aftermarket valve body - it shifts nice and firm).

I wired up a manual TCC lockup switch - trans doesn't respond.

Please let me know if more information would be helpful.

[ipz2222]

If you have the manual tc switch wired correctly, then youhave a defective converter, stuck tcc apply valve, cut tcc o ring, or bad tc solenoid, and no it can not be changed by itself, it's part of the solenoid assy.

[PSDGuy]

It is just grounding the violet/yellow wire (can't remember which pin) coming from the transmission pigtail - so I assume it is correct...

[PSDGuy]

So I took it to a tranny shop this morning, they pulled codes, took it for a drive, and said it was locking just fine. I argued that it is not locking, but they said it was doing what it is supposed to do...

Am I missing something? When I run it up above 45-55 mph shouldn't I feel it lock (RPMs drop, maybe a slight acceleration)? And when it does lock, I shouldn't be able to push the throttle slightly with the motor increasing by 200-300 rpm (without relative acceleration), right?

[ipz2222]

What you're describeing does sound like it is slipping. On the scanners,(Snap On, Mentor, Genisys etc) there is a PID for tcc slip. Snap on calls it "tccmact".
That PID will show how much , in rpm's, the trans or tc is slipping. Should be less that 15.