Hello all.  New here......Just picked up a 98.5 2500 Auto trans 255K

 

I have no cluster and says  “No Bus”.  Ive checked all the grounds cant find anything wrong. 

I got the truck from a friend of a friend and he said the cluster went out like a month after he had work 

done to the trans . My edge Insight only has code P1698 “no transmission bus messages”

truck runs and drives fine and has for I believe years since the cluster went out 

Anyone got any ideas ????

 

I also need to reseal the vacuum pump anyone have any trick of in seas to make that job easier ?

 

Thanks.  

Edited April 29, 20205 yr by Acetcruiser

 

Thanks Mopar1973man.    Can this be done with an edge insight cts?   
ive ohmed out the ground from the battery to after where it splits at the pcm and was good.   

I seen a video where it was caused by a bad part n the trans itself but can’t find the video again...

Seen the video befor I knew he problem was linked to trans

Edited April 29, 20205 yr by Acetcruiser

You can check voltage of the bus in the obdii port. 2.49 and 2.51 volts in reference to body ground. This is bus + and bus -.

Do you have a pic of the pin out on the port where I need to check voltage.?     

Yeah... Pin 3 and 11 in the OBDII port to ground. 

 

 

Edited April 30, 20205 yr by Mopar1973Man

Thank you.... I’ll check it out tomorrow spent today resealing the vacuum / ps pump.  

Hopefully  that’s fixed. Looked good so far I’ll see if there is a spot on the ground in tomorrow.

While i was doin that job i had to remove the inner fender and seen some plugs and they didn’t look

to good.  Wonder if the wires i found could be where my problem is?

@Mopar1970man     On pin 3 I have 2.54 volts nothing on 11. Or should 11 be the ground?  
. Thanks

Edited May 25, 20205 yr by Acetcruiser

No... 2.51 and 2.49 volts in reference to ground. So the pin 11 is short to ground or open circuit.

@Mopar1973Man     Do you have any suggestions where I should look now?   Thanks

Call Auto Computer Specialist see about having the PCM on the firewall sent in for testing.

 

Double check by unplugging all extra modules, like factory stereo, overhead trip, central timer. Look for voltage on pin 11.

 

Might be good to do W-T ground mod to reduce chances of AC noise damage. Then do the PCM protection fuse too (optional but suggested).

@Mopar1973Man    Thank you for the help.  I will try to unplug things. I don’t have factory radio but I’ll unplug what I got.   What and where is central timer?   Question.  If I do find the problem say unplug one thing and see if code goes away then I’ve insulated the problem?   Cause I believe it’s my trans Causeing the problem so say unplug it power on the key clear codes and see if it comes back ?   Thanks again

Central timer is above the throttle pedal in the dash.

 

Go look at the CCD network article in the 2nd gen Electric articles wire map and what causes the code. CCD+ and CCD- should be 2.49 and 2.51 volts. Since there is ZERO on one side its either a short to ground in the computer or device or open connection.