PCM bad?

[HitCast]

First post here, a pleasure to be here! I’ve been fighting with my gauges for a while now and it’s driving me insane. I have read many pages on here and other forums but have not found an exact answer or fix. My tachometer works, all other gauges inop my transmission shifts great. When I connect my scanner (Snapon Zeus) I can pull codes out of the ecm and get codes P1698 (No transmission bus messages) and P0230 (transfer pump circuit out of range) I believe that is due to the airdog. Many of my dummy lights are on. The wiring in this truck is a nightmare due to the previous owner. Any help would be greatly appreciated!

[Haggar]

Hit,

Welcome to the forum. 

 

I hope some of the people that have seen this will post up with good suggestions on where to start.  But it will certainly involve figuring out what series each of your computer modules are from and pick the best combination with your wiring.  

Here is for testing the P0230

Cluster issues can be fun.  Most of the information displayed on the gauges are not direct from the sensors, but are part of the data bus information passed between modules.  So troubleshooting is a bit more ugly.

 

GL

 

Hag 

[JAG1]

There are a few guys corrected a similar problem by messing with the instrument cluster connection, which I'm not familiar with, that they say is under the dash behind the factory gauges. One guys long standing problem was solved just by clicking it in tighter. Another found a bent pin something along those lines anyway. Then if I remember correctly, there is another problematic pin connector behind or near the radio that another guy found was the problem. Drove him nuts for a long time trying to find the problem.

 

Anyway I hope something simple like that will get you going..... Welcome to the 'truck club' BTW.

Edited January 14, 2020 by JAG1

[Great work!]

The overhead display (if equipped) is connected to the same bus. If the outside temp works and the overhead trip mileage increments while driving then the PCM is probably ok and its a wiring issue.. 

[HitCast]

Thank you guys for the input so far, sometimes these issues make me miss my first gen!  I’ve checked the connectors behind the dash they seem okay but never really clip in they just sit in the plug, sadly the overhead console does not work (previous owner) pulled that harness out and the cab light harness I just found a used overhead console for 20$ so it finally has an overhead console just has to be wired

 

[dripley]

Welcome. Problems ofmthis are out of my realm for sure.

[dave110]

Here's my story with that issue. My gauges would flake out at will. Sometimes the tach would go first, sometimes the speedo, but usually all gauges would die and all dummy lights come on. I'd also always get a no bus message on the odo that would start out flashing and then get solid. I started noticing a pattern, that being it would often fail and then fix itself after a bump. Soon I could usually fix it by hitting the cluster or dash top with my fist. Busted my bezel trim that way. I knew then something was loose so I pulled the cluster and like you said the plugs just sit there. I believe that over time the plastic clips that hold the plugs relax and they become loose. So I put some dielectric grease in them and stuck a toothpic (because that was the first thing I found that looked about right) behind the plug between the plug and the dash base. This tightened it up and now when the cluster gets put in it pushes into the plugs instead of pushing the plugs away and not seating correctly. That was back in spring and the problem has never come back. That being said I did NOT have a DTC like you do so might be another issue.

 Oh, and CFA has toothpics for free.

[dripley]

8 minutes ago, dave110 said:

Oh, and CFA has toothpics for free

Now thats something I can sink into my teeth.

[dave110]

Don't break them. I hear hens teeth are pretty rare  

[HitCast]

1 hour ago, dave110 said:

My gauges would flake out at will. Sometimes the tach would go first, sometimes the speedo, but usually all gauges would die and all dummy lights come on. I'd also always get a no bus message

 

Sounds close but my tachometer always works and the rest never work at all, it’s odd because the water temp gauge shows nothing but my adrenaline will pick up water temp but nothing about the speedo

[dripley]

Electrical gremlins are mysterious creatures. I have fought some thru the years and won but still not sure how I won most of them.

[HitCast]

1 minute ago, dripley said:

Electrical gremlins are mysterious creatures. I have fought some thru the years and won but still not sure how I won most of them.

Oh man, they drive me crazy I’d rather the trans go out on me, because then at least I could just build it and move on electrical mysteries are like chasing your own tail 

[dave110]

34 minutes ago, HitCast said:

Sounds close but my tachometer always works and the rest never work at all, it’s odd because the water temp gauge shows nothing but my adrenaline will pick up water temp but nothing about the speedo

When mine went wacko I could still read everything through my Scangauge2, even the speedo.