I was on a road trip this weekend when my check engine light came on. I pulled over and did the key trick just to see what I could find. It came up with these:

 

P0500

P1687

P0237

 

I know the P0500 code is probably from spinning the tires on some gravel or something. The other 2 have me wondering though. I have noticed some slight power issues lately that I didn't realize could be MAP related but its almost like the sensor is coming and going. Sometimes I can black out the sky and sometimes it feels like about 1/2 power.

 

I haven't disconnected the comp yet to see if that effects anything. I will do that tonight and clear the codes.

 

As for the 1687, what does it mean when it says no cluster bus? I did a gauge check and they all seem to work fine. I haven't noticed any issue with the cluster at all. everything works just how its supposed to. I don't have the overhead computer either so there isn't a problem there.

 

Could the 1687 code and the 0237 code be related at all? I don't think so but it was kind of weird when they both came up at once.

 

Note: I already read through the diagnostics in the Error Code articles, just trying to understand what is actually going on with these systems before I dive in. Thanks everyone!!

P0237 is a MAP sensor code and the P1687 is a CCD Network communication error. As for doing the check gauge feature that just test the cluster to see if the cluster is fine but does nothing to test if the CCD network is talking to the cluster.

 

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/167-p0237-map-sensor-voltage-too-low

 

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/226-p1687-no-cluster-bus-message

 

Well I cleared the codes tonight and drove around a bit. None of them came back so that is a good sign. I will drive it to work tomorrow and thats a good 15 miles each way so if there is an issue, hopefully it will throw a code again.

Well I took the Comp box off the truck and cleared the codes again. No codes have come back and I have driven about 25 miles since the clearing. Looks like the boost fooler must have died in the Comp. Really sucks!!

So because I dont have a scan tool of any kind, could I still test the signal voltage by pinning the signal wire and using a DVM to watch the voltage? Or do I really just need a scan tool...

 

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/167-p0237-map-sensor-voltage-too-low

Yea, you can do it that way. Just use a paper clip and back probe the connector.

Ok. I thought I probably could but wanted to double check.

 

Another issue that came up this morning is the alternator seems to not be charging that much at idle. If I am going down the road it works just like it is supposed to holding just over 14 volts. As soon as I drop the rpms to idle like at a stop like or whatever the volt gauge drops down to about 12. This just started happening this morning.

 

Any thoughts on this? No codes have shown up for anything and the battery light hasn't gone off yet.

 

Thanks in advance for any help!

Big shout out to Edge. Just got off the phone with them and they said send the comp in. They will fix it at no charge to me. Very good people to work with.

Ok. I thought I probably could but wanted to double check.

 

Another issue that came up this morning is the alternator seems to not be charging that much at idle. If I am going down the road it works just like it is supposed to holding just over 14 volts. As soon as I drop the rpms to idle like at a stop like or whatever the volt gauge drops down to about 12. This just started happening this morning.

 

Any thoughts on this? No codes have shown up for anything and the battery light hasn't gone off yet.

 

Thanks in advance for any help!

Will, I took the old "clamp style" battery terminals off and swedged on new marine style ends on the battery cables. Before the voltage sat in the 12's even at idle and once the alternator came up on speed the voltage would come up but not now.

Now its immediate full voltage (I have a digital volt gauge)  and once the engine is running, even at idle, its 13;7 volts with the better terminals, so you might look into giving that a try. Your being up in Missoula (I used to live in Helena) and you really need good power to get going up in the mountains in Winter.

 

This is what they look like: http://s876.photobucket.com/user/joeaksa1/media/Dodgemainbatteryconnections_zps3b499a0b.jpg.html

 

FT

Edited December 11, 201410 yr by FlatTwin

That would make sense. I am still running the factory battery cables on this truck and they are starting to look a bit shotty. I know I will have to replace the cable that crosses over between the batteries pretty soon. Maybe it is time to just do all the cables and call it good. 240k miles, I think it couldnt hurt to replace.

I took care of my cables and batteries from day one so my cable are still in excellent condition and no replace or modification required.

I usually do too but there was a small problem. I purchased this truck with about 180k on the clock. For the most part the truck had been taken care of pretty well. Things like this were unfortunately overlooked though.

 

On another note, I got the Comp back the other day. Apparently my module was to old to fix so they just sent me back a brand new module and harness for $100. They even through in the Hot Unlock because my old comp had it. Holy cow I dont know what the difference is but this Comp seems to light the truck up way more than the old one did. Night and day difference!! I am very pleased with the service and product.