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Transmission key pad blinks “Do Not Shift”
We are in a safe place, put unable to shift the bus into gear. After engine start the transmission key pad flashes “Do not Shift”. We are located in Chilhowie, VA. Thanks looking for any advise or help!
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29 Replies
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Was this after starting up a cool engine or after a momentary stop after running for a few hours?
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It was after a 10 hour drive. we got the flashing light and nowwith a cold engine, as soon as I turn the key on the light flashes.
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Monty,
It could be a sensor that thinks the transmission is cold. Have you tried running on high idle and letting things get warmed up?
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What is your cellphone number?
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Tom,
As I was relocating the bus last night (it was still hot from the trip). after starting and in Hign idle the flashing light was still on. Wasn’t able to move bus!my cell 607-684-4508… Thanks
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I had a similar issue once. Called Prevost and they asked me to check the breakers in the rear electrical bay. I forget the exact details, but one of them was popped and the ECU wasn’t getting some information it needed about the transmission. Reset it and it’s been fine ever since.
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Had a problem a few times in the past, where I could not shift out of “N”. Not sure what caused it but I played around with the shift pad and got it working. Problem is, I don’t remember the exact steps. But try this:
Key off
High Idle switch off
key on, engine not running
Hit “N” on key pad
hit the mode switch on key pad, mode lite comes on
Hit mode switch again, mode lite goes off
Key off
Start engine
Try to shift.
If that doesn’t work, repeat the steps above, but instead of the mode button, hit bith down arrows at the same time.
It was some combination of the above steps that got me going again. It was like the shift pad was “confused” and needed to be reset/unconfused.
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Monty,
A bad temperature sensor can cause the error message, but so can an idle speed that is too high. Mkae sure it is at low idle. I would play around as Andre suggests, but one thing that created an issue like that on our first bus was corrosion in the 28 pin connector at the transmission. If you run out of things to try you might consider sliding under and unplugging the electrical connector a few times to see if the in and out motion of doing that can clean any possible corrosion.
I think you have a way to flash transmission codes and if you can do that it might offer a clue as to what is happening.
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Monty has an 8V92 and 5 speed, a different animal than the 6 speed.
Monty – Is there a ATEC switch in the steering compartment? If so, that will give you the blink codes so you can determine what’s wrong. The codes should be in the Allison manual.
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None of the previous suggestions have worked to clear the code.
I flashed the memory and came up with code 16-Coolant Sensor Hi Volt and 85- Engine overspeed. Any ideas what to do next?
Is there a way to clear the codes from the transmission ?
Looking for any ideas!
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Have you tried disconnecting the harness to the keypad, waiting ten seconds, and plugging it back in?
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Rebooting the transmission and engine ECUs might be worthwhile. For that you’ll need to turn off battery switches and remove the negative battery cable from the engine batteries. (Not sure if the ECU uses 12v or 24V, thus the negative cable.)
If this does not help I’d would look for oil contamination on the transmission ECU and sender connector(s). Clean and put dielectric grease on connections.
Gerald
1999 XLV X-6872, liberty #440 -
This is stupidly simple but my 8V92/HT755 started flashing ‘do not shift’ and shutdown once at 3AM. Low on atf…have you checked?
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Those look like engine codes Monty, not transmission.
For you 5 speed guys, would DDEC code 16, Coolant Level Sensor, prevent a no shift for the tranny? If so, he could jumper the coolant sensor and see if that corrects it.
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If all else fails, call the Prevost PASS line at 1-800-463-7738
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