Range inhibit

[Davenport]

I have a 2007 Bluebird Vision with C7 Cat engine and a allison trans. The bus started no problem but the check trans light came on and then when I put it in gear the range inhibit light comes on and the bus will not move. Does anyone have any idea on what this issue is or how to resolve it?

[Sehnsucht]

Good news is it's usually not an actual transmission problem. RV and medium-duty truck forums report ths routinely and it usually involves simply disconnecting the battery for five minutes then reconnect. The bad news is that's not usually a one-and-done resolution because the issue is usually traced back to a bad ground somewhere in the electrical system. Electrical gremlins are frustrating and more so on school buses because of the surplus electricals. If you've started stripping out the school bus lights and stuff you may have inadvertently caused the issue.

[cadillackid]

this could be a lot of things.. im guessing this is a pushbutton MD-3060? the rasnge inhibit can be an issue with the trans but also if you have removed anything like esp taken out a wheel-chair lift there can be a connection to the transmission to inhibit it from going into gear if say it thinks the lift is deployed..

[Sehnsucht]

Originally Posted by cadillackid

this could be a lot of things.. im guessing this is a pushbutton MD-3060? the rasnge inhibit can be an issue with the trans but also if you have removed anything like esp taken out a wheel-chair lift there can be a connection to the transmission to inhibit it from going into gear if say it thinks the lift is deployed..

Yes, a wheelchair lift is exactly the kind of school bus feature that would disable the transmission if removed.

[ewo1]

Originally Posted by Davenport

I have a 2007 Bluebird Vision with C7 Cat engine and a allison trans. The bus started no problem but the check trans light came on and then when I put it in gear the range inhibit light comes on and the bus will not move. Does anyone have any idea on what this issue is or how to resolve it?

More details required.
2 very good questions asked…

Which transmission model do you have and do you have a wheelchair lift?

[Davenport]

Originally Posted by ewo1

More details required.
2 very good questions asked…

Which transmission model do you have and do you have a wheelchair lift?

It is a Allison 2000 and no wheelchair lift

[Davenport]

Originally Posted by cadillackid

this could be a lot of things.. im guessing this is a pushbutton MD-3060? the rasnge inhibit can be an issue with the trans but also if you have removed anything like esp taken out a wheel-chair lift there can be a connection to the transmission to inhibit it from going into gear if say it thinks the lift is deployed..

no it's an Allison 2000 and no wheelchair lift

[ewo1]

Originally Posted by Davenport

It is a Allison 2000 and no wheelchair lift

Thank you, this helps set the direction for helping you.

Take a look in the battery box, there should be an extra wire or two, much smaller than the battery cables.
You should be able to locate one if not two inline fuses.
Both the engine ecu and tranny ecu are fused.

Locate them and see if they are good or not.It is obvious the engine ecu is working so you need to verify that power is getting to the other.

That’s the first step in this process.
If the tranny ecu, aka TCM, that will cause the shift inhibit or limp mode and the check trans light to come on.

Also check your tranny fluid level, is it bright red, dark red or black/ burnt?
That is important to know.

[Davenport]

Originally Posted by ewo1

Thank you, this helps set the direction for helping you.

Take a look in the battery box, there should be an extra wire or two, much smaller than the battery cables.
You should be able to locate one if not two inline fuses.
Both the engine ecu and tranny ecu are fused.

Locate them and see if they are good or not.It is obvious the engine ecu is working so you need to verify that power is getting to the other.

That’s the first step in this process.
If the tranny ecu, aka TCM, that will cause the shift inhibit or limp mode and the check trans light to come on.

Also check your tranny fluid level, is it bright red, dark red or black/ burnt?
That is important to know.

It is like medium bright it looks to have been changed before I bought it

[ewo1]

Originally Posted by Davenport

It is like medium bright it looks to have been changed before I bought it

Ok, take for a better explanation of what might be going on, take a look at post #3, by Caddilackid, in this thread

He does a better job of explaining the tranny processing.

But you need to check your fuses first!