Does anyone know where to find a diagnostic tool for the 4L80E? I

[kingConan]

Hi!
I've been doing the field diagnostics and keep getting an unspecified code. Transmission was just rebuilt, shifts fine for a bit then goes back into limp mode. All solenoids and sensors have been replaced. Any help would be great!

 

[Mogman]

What is the unspecified code?

 

[kingConan]

What is the unspecified code?

I believe it's an 83. It's been in the shop for 5 months now. I'm in Portland Oregon so there's that. I will be able to confirm with the shop on Monday.

 

[Mogman]

Do you need the 4L80E supplemental troubleshooting guide?
If so I will post it.
I understand you are just working from memory so the code you speak of may actually be different

 

[kingConan]

View attachment 928954
Do you need the 4L80E supplemental troubleshooting guide?
If so I will post it.
I understand you are just working from memory so the code you speak of may actually be different

No, I have it. Thank you though.

 

[NDT]

I would ring out the harness between the controller and the 4L80E. Sounds like you got an intermittent connection.

 

[kingConan]

I would ring out the harness between the controller and the 4L80E. Sounds like you got an intermittent connection.

What does ring out mean? Go through the harness and rewire it?

 

[NDT]

By ring out I mean to check that each wire in the harness has continuity from one end to the other. No fraying or bare spots.

 

[kingConan]

By ring out I mean to check that each wire in the harness has continuity from one end to the other. No fraying or bare spots.

Yup. Gone through everything. Repaired and replaced wires and pins.

 

[Retiredwarhorses]

Yup. Gone through everything. Repaired and replaced wires and pins.

A “good” transmission shop should be able connect up the TCM with the snap-on Diag tool and take the place of the TCM, my shop does/did for an issue I had…the TCM in the box is nothing special and with the schematic, a good tech can make up a quick harness to interface the tool to the plug, it doesn’t require all the pins be used.
My Tech was able to see that on one particular truck, it wasn’t seeing a response ”BACK” from the TCM on a particular function, so he figured the wire from the body Harness at the transmission to the TCM plug was bad, he ran a separate wire bypassing the wire on the outside of the truck and the transmission operated as it should, I ran a more Permanent wire once back at the shop and that was that.

 

[kingConan]

A “good” transmission shop should be able connect up the TCM with the snap-on Diag tool and take the place of the TCM, my shop does/did for an issue I had…the TCM in the box is nothing special and with the schematic, a good tech can make up a quick harness to interface the tool to the plug, it doesn’t require all the pins be used.
My Tech was able to see that on one particular truck, it wasn’t seeing a response ”BACK” from the TCM on a particular function, so he figured the wire from the body Harness at the transmission to the TCM plug was bad, he ran a separate wire bypassing the wire on the outside of the truck and the transmission operated as it should, I ran a more Permanent wire once back at the shop and that was that.

Great information. Thank you

 

[badger_610889]

I must be dumb, but:


OK so we can wire pins A and E of the J2 connector, then what?
I’m trying to figure if I could get to properly use the diagnoses capabilities of the transmission controller. RetiredWarhorse, I’m wondering about the snap-on tool you mentioned?

Thanks!

 

[Mogman]

After you connect A and E then you switch on the run switch and read the codes on the trans light.
You will find the instructions on page 60 of the supplement.

 

[badger_610889]

Thanks Mogman. I actually read through it since, and got the info. But your help is tremendously valuable!