Southampton diesel

Gotta love my luck. It seems this Mack is wired differently than it should be. I found continuity on vj2 9 but the lettered wire I cannot find

Gotta love my luck. It seems this Mack is wired differently than it should be. I found continuity on vj2 9 but the lettered wire I cannot find

And still low power. I just don't understand how the speedo is working and I'm showing no continuity

Thanks for the reply Mack farmer. My boost sensor was irradic so I did change it. But I'm still getting the low voltage code for the speed sensor. And still have no continuity between vj2 11 and 12. I did notice the wires at the speedo are vj2 9 and 41-a-8.0

I realized that last night also. I have moments like that myself. Especially the older I get. I'll dig into at some point today

Does anyone know if both wires go through the bulkhead connector? I realized the wires at the speed sensor have different numbers on them. So my guess is those wires tee off, one set to speedo one set to ecm. I'm pretty much learning as I go along haha

No just a two wire. I went through the great previous info top to bottom and have no continuity between the two. My check engine light would come on and off last month but the truck ran great. Then all of a sudden the light stayed on and the truck lost substantial power

Not sure how there is no continuity yet the speedo is working!

Well I have some interesting news. All the wires look good. Pins ten and eleven have no resistance at the plug at all. Nor are any pins shorted with another wire. I believe this is going to be a project.

Thanks so much for the detailed post. I was away for a few days but I'm going to dig into it now I'll keep you updated

Thanks for the response. That's what I was gleaning towards. Just not to sure on where to go it's got a spn85 fmi 4 fault. Which is voltage less than normal. Before I changed the speed sensor it was a different fault. I'm just not sure where to look next. Both wires are reading .2 volts. I'm not much of a Mack man, but from reading earlier posts there are sure a bunch of you on here

Hi all,

I am brand new to this forum, but have found lots of useful info already. I have a 2004 Mack cx613 that is experiencing low power. It started out of the blue. With an unloaded trailer it struggles to get to 50 mph. Low boost pressure also. The only fault code in it is road speed voltage to high. I changed the sensor and now my speedo works but same low power same code. Just wanted to ask some more seasoned Mack guys if I'm going in the right direction looking into that fault code. I traded my Volvo in on this one and now I'm having regrets. Any help would be much appreciated