How does dual switch brake pedal work ?

Folks, I was finally able to do the testing. I disconnected the TOSS and went for a drive…. Terrible performance Than I reconnected the TOSS and disconnected the TISS, went for a drive…..

Stopped and performed the transmission code testing…. And NOTHING!!!! No codes stored…. Again 1,2. 1,2. 1.2. 1.2 ………

I hate to get to this conclusion, but I think the problem is with the TCU, correct?

Your input is much appreciated.

Mastherr said:

Folks, I was finally able to do the testing. I disconnected the TOSS and went for a drive…. Terrible performance Than I reconnected the TOSS and disconnected the TISS, went for a drive…..

Stopped and performed the transmission code testing…. And NOTHING!!!! No codes stored…. Again 1,2. 1,2. 1.2. 1.2 ………

I hate to get to this conclusion, but I think the problem is with the TCU, correct?

Your input is much appreciated.

Click to expand...

I do not think the TCM stores codes, so the TOSS may have cleared when it was reconnected, the supplement should describe what clears the codes (besides disconnecting the batteries)
It does seem to point to a TCM issue.
IIRC some codes would clear when the vehicle was shut off and re-started if the condition was no longer present.

Do you guys know any specific test to the TCU to make sure it’s the culprit? ….. don’t want to spend that kinda a money unnecessarily. Tks

I do not know of any specific test you could do to prove the TCM was bad but lets recap.
1, You can put the TCM into diag. mode so the TCM is getting both sources of power it needs to work. (continuous 12V and switched 12V)
2, You can disconnect a sensor that should set a code and turn on the trans warning lamp but it does nether.
If you unplug the TOSS and drive the truck to at least 3000 RPM you should get a code 24 TOSS circuit low.
I am sorry, I used to have a loaner TCM I would send out but I had to use it on a build so it is no longer available.