P0742 Shift Range Inhibit

[Krazykid]

OK short history. I have been getting this shift range inhibit message both before and now after having the SC IV kit install. Now I have NOT yet pushed the Trans since picking it up Friday. Today after my sons hockey practice we got home and got the message when shifting into park. Scanned with EFI Live and found P0742 code. Only code stored in PCM,TCM.

Code: P0742
Modules: PCM, TCM
Description: Torque Converter Clutch (TCC) System - Stuck On


How is this fixed? Thanks for everyones help.

 

[Mike L.]

First of all make sure that you actualy cleared the code.
You need to monitor the TCC solenoid and make sure the clutch is coming on, 96 or 97 %. Watch the RPM slip speed after TCC apply and see how much RPM slip you have if any; there should be none so you must see 0 RPM slip.
If those numbers are correct you need to monitor turbine speed sensor at about 30 mph ( no TCC applied ) and the RPM numbers should be 200 rpm or more depending on throttle position. ( the numbers will increase as throttle is increased ).
P0742 usualy indicates that the TCC is on when it shouldn't be and the truck will feel like the brakes are dragging when yo accelerate.

 

[racinmike77]

did you shim your converter flow valve?

 

[Krazykid]

Trans was built by a transmission shop locally. If that was listed in the SC IV kit directions then I would say yes, if not then no it was shimmed.

 

[Krazykid]

First of all make sure that you actualy cleared the code.
You need to monitor the TCC solenoid and make sure the clutch is coming on, 96 or 97 %. Watch the RPM slip speed after TCC apply and see how much RPM slip you have if any; there should be none so you must see 0 RPM slip.
If those numbers are correct you need to monitor turbine speed sensor at about 30 mph ( no TCC applied ) and the RPM numbers should be 200 rpm or more depending on throttle position. ( the numbers will increase as throttle is increased ).
P0742 usualy indicates that the TCC is on when it shouldn't be and the truck will feel like the brakes are dragging when yo accelerate.

Can all do this all with EFI? I am assuming yes. Also this issue does NOT happen all the time.

 

[Mike L.]

Can all do this all with EFI? I am assuming yes. Also this issue does NOT happen all the time.

I don't use EFI so I can't tell you. Someone here will be able to tell you if it can be done.

 

[Krazykid]

Thanks Mike.


anyone have information on mikes post about the TC?

 

[duramaximizer]

I am pretty sure you can, you just have to connect to the LB7/LLY Allison TCM.