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Ragtop69GS · 02-16-2019, 07:21 AM

I'm trying to help out a friend that has a 1994 Vectra diesel 5.9/ MD3060 drivetrain on a Spartan chassis.

He is having transmission control unit problems, the coach would not start so he cleaned the connector at the trans and the coach started once or twice then would not start again. He now suspects the TCU may be bad and wants to run through the troubleshooting but, he can not find the TCU on his coach! does anyone know where Winnebago hid the TCM ?

Wroughtnharv · 02-16-2019, 07:38 AM

I believe the plug is under the dash. With the ignition on there is a trouble shooting program on the trans control. I don’t recall the exact sequence but it involves pushing two buttons as the same time, numbers will appear, and those numbers can be crosschecked with a code explainer to see what’s going on.

Ours is a 93 with the same motor trans. I had a service alert and it turned out to be a common down shifting issue that Allison no longer supports. Trash trucks use the same trans and our mechanic said it is something recommends learning to live with.

Is there any chance the starting issue is a fuel delivery issue?

Ragtop69GS · 02-16-2019, 08:19 AM

Quote:

Originally Posted by Wroughtnharv

I believe the plug is under the dash. With the ignition on there is a trouble shooting program on the trans control. I don’t recall the exact sequence but it involves pushing two buttons as the same time, numbers will appear, and those numbers can be crosschecked with a code explainer to see what’s going on.

Ours is a 93 with the same motor trans. I had a service alert and it turned out to be a common down shifting issue that Allison no longer supports. Trash trucks use the same trans and our mechanic said it is something recommends learning to live with.

Is there any chance the starting issue is a fuel delivery issue?

He is trying to locate the transmission control module, to test the pinouts for power and ground issues. If that all checks out good then he will send out the TCM for a rebuild, but first he has to find where Winnebago hid the TCM. The pinouts testing sequence is available online.
http://www.transmissioninstruments.c...eshooting.html
He is a days drive away so I'm trying to help long distance. It is not fuel related, it's definitely a trans control issue.

I just went through this on my coach and ended up having to replace the TCM.

Wroughtnharv · 02-17-2019, 08:08 AM

There’s an aluminum box under the dash that has an umbilical cord going to the shift panel. That might be what he’s wanting to find. It’s about the size of two eight track tapes stacked.

I just checked for access to under the dash and that is difficult. We have the shades in place and I would have to remove one to open the door. The driver’s compartment is now used for storage until we rearrange for the trip home.

Sorry

Ragtop69GS · 02-18-2019, 07:08 AM

Quote:

Originally Posted by Wroughtnharv

There’s an aluminum box under the dash that has an umbilical cord going to the shift panel. That might be what he’s wanting to find. It’s about the size of two eight track tapes stacked.

I just checked for access to under the dash and that is difficult. We have the shades in place and I would have to remove one to open the door. The driver’s compartment is now used for storage until we rearrange for the trip home.

Sorry

I'll have him look there. Thanks.