1078 won’t start

[Mekanik]

I’ve got a 1078 in my bay that won’t start, the transmission’s physically in neutral but the dash selector switch is giving me a code not in the TM. When I pull the neutral start relay out of the pcb the green LED lights up and I can jump the starter with a screwdriver. When I put the relay back in the LED light goes out and I can’t bump start it or use the buttons in the cab to start. I’ve tried using new relays but I get the same result. I’m at a loss and need some help. Thanks

 

[NDT]

What is the code? Do you have access to the Allison troubleshooting guide? What year is the truck?

 

[Mekanik]

What is the code? Do you have access to the Allison troubleshooting guide? What year is the truck?

The only code I can get to pop up is a 0 with and X in the middle then after a few seconds it changes to something people on the internet call “cat eyes”. It’s a 2004 and something I forgot to mention in my earlier post was two mechanics had this before me and they replaced the entire pcb as well as the VIM and I hadn’t tried the Allison troubleshooting guide yet but I’ll do that now.

 

[NDT]

Well that is why your truck won’t start, if the WTEC controller isn’t happy it will start inhibit. Get the WTEC up and happy with no codes and she will crank normally with any luck.

 

[Mekanik]

Well that is why your truck won’t start, if the WTEC controller isn’t happy it will start inhibit. Get the WTEC up and happy with no codes and she will crank normally with any luck.

I reset the codes, worked for about half a second but it still shows the same codes. Is the WTEC controller not happy because the pcb and VIM were replaced? Is there some sort of flashing that needs to be done in order to get them to communicate properly?

 

[NDT]

Can you ask the previous people that worked on it what was the original issue? If the WTEC showing cats eyes was the original problem, they went down the wrong road. Since now they have jacked around with all the wiring, many additional issues may have been introduced. Nevertheless, if it were me, I would send the WTEC controller in for diagnostics. The VIM just has relays inside, no digital communication with WTEC.

 

[Mekanik]

Can you ask the previous people that worked on it what was the original issue? If the WTEC showing cats eyes was the original problem, they went down the wrong road. Since now they have jacked around with all the wiring, many additional issues may have been introduced. Nevertheless, if it were me, I would send the WTEC controller in for diagnostics. The VIM just has relays inside, no digital communication with WTEC.

The original problem was the charging system light was on as well as the trans light. From what they told me, they diagnosed the the trans light as a bad pcb so they replaced it but the kid who installed it did put the 24v and 12v wires backwards, that problem is fixed now, so they ended up replacing the VIM and the TCM.

 

[NDT]

So you are saying they smoked the original WTEC controller, and sourced a new one, and now this new one is giving you cats eyes? Again I would send both controllers in for diagnostics.

 

[Guyfang]

Normally you would open a thread in the LMTV forum for this problem. I will move it over for you.

 

[Ronmar]

Ok, first off, you don’t have a VIM on a 2004. You have a trans keypad/shifter in the drivers dash and a trans controller under the passenger dash(where the vim was located on the A0). The A1 only feeds 24V to the transmission for both battery power and IGN. CB43 should provide the batt power and CB79 should provide the IGN power. The A1 schematics are here in the schematic section, I would confirm batt and ign power are reaching the connector pins. Here is a pic of part of the schematic…


cats eyes - - i believe indicates that power is applied but things are not communicating. You could have a cabling/communications issue between the controller and keypad. Unfortunately the drawings for the A1 do not show the controller to keypad wiring, just like they don’t show the engine side of the ECU.

Where did they source the replacement control module? Does it have the appropriate program and is it the right config for the transmission? allison made all kinds of variants and they don’t all mix and match…

The only place I have seen “O X“ referenced is when the controller is checking the oil level using the installed sensor. The military did not opt for the oil level sensor on our transmissions so that brings me back to thinking this controllers program may not be compatible and it is getting confused upon power up.