Has anyone ever heard of getting a speedometer signal code (3-1-1) and yet their speedometer worked fine? I just installed a factory cruise unit yesterday and it didn't work. One thing it says on ALLDATA is that the speedometer must be functioning for the cruise to work. Well my speedometer works great but apparently the signal to the ECU isn't good. Has anyone had any experience with this particular code before and if so does this mean I need to replace the VSS sensor?

Thanks,

Dale

 

Where did you tap into for the cruise signal?

 

I didn't have to tap into anywhere except the factory connections. What I've learned today is that the speed sensor sends the signal to the speedometer, and the speedometer sends the signal to the ECU through wire 6 at the back of the cluster. I just installed a new (well used) cluster about 3 weeks ago that came with a tach so there's my suspect problem right there. So I went out with my trusty vacuum pump, checked the switches, they were all working good. The throttle vacuum diaghram leaks just a little but I'm sure the vacuum pump could compensate. Tomorrow I'm going to make sure the vacuum pump works and it gets power after the threshold is reached at 22mph. Stay tuned, I'll get to the bottom of this!!!

 

Well I still haven't found the 311 code problem but I think I'm hot on the trail. Look at the pic below to see the differences between an '87 and '91 cluster. People sell these things on ebay claiming they'll work in the 240's from '86 to '93, BUT, I think (and will try to prove this wrong today) that this isn't the case. My 311 code started after I installed an '87 cluster into my '91.If you look at the backside of the clusters there are physical differences in resistors (some are there and some are not) along with the '87 cluster having an extra pin on the lower connector. I may be all wrong on this one but I'm guessing the speed signal to the ECU from the clusters is somehow a little different, just enough to confuse the ECU and log a code 311. We'll see later on today because I changed everything over to my original cluster (tach, temp. compenstor board) and will be installing it this morning.

 

I am pretty sure you need a cluster from the same year as your car. Last year I tried to fix the speedometer with a different cluster, ones from 87-89 none worked. I needed one for 90 even though they look the same the connectors in the back was different.

 

After looking at this thing for a while now I also believe the circuit board to be from a diesel (the one I bought off ebay). On thebottom where the idiot lights are, one of them is a glow plug message, I highly doubt the gas circuit boards come with a disabled glow plug idiot light. Again I guess it's possible but doesn't seem too likely to me. I just installeditin my car and luckily thetemp. gauge works, which proves my temp. compensator board in my original cluster was bad, (I robbedit from the ebay cluster). So far sogood, I need togo for a hard run to see if I get the 311 code. Will report back later.

 

Well here's the final chapter on this problem. My 311 code was infact caused by the installation of a different instrument cluster. By reinstalling my old cluster with (speedometer from the ebay one because it was satin like all of my other gauges, and the temp. comp. board because my temp. gauge didn't work) all now is fine. My idle is back to normal, a nice steady drop to a solid 750, (it was dropping to 500 then bouncing back to 750 when I pushed the clutch in), no codes, and best of all my cruise control that I bought off ebay is now working!!!wooohoooo!!!! It uses the speedometer signal to the ECU to calculate speed, of which the ebay cluster was screwing up on the way to the ECU.

So the moral of the story is, if you buy an instrument cluster off ebay or anywhere else, be sure the back side of it looks identical to the one you have in your car. Don't go by the "K" number below the tripometer, those bascially mean nothing when it comes to the circuit board that everything is attached to. Actually you can tell by the "K" number if it's for a sedan or wagon, BUT, still don't buy one until you can verify it's identical to the one you have!!

Am I ever glad that chapter is over!!![sm=wootwoot.gif]

 

Glad all is fixed and working!!!

 

Hey,
I bought a '91 DL sedan last fall. The speedometer wasn't working. I replaced the sender on the differential and then the speedometer started working but reads 5mph fast.
My car is gas but I also have the diesel glow plug light and when I took out the cluster it's been written on like it's from a salvage yard. I'm also getting a 3-1-1 error, sort of rough idle, not like the smooth idle of my turbo wagon, and sometimes the sedan dies if I slow down really fast after it's been running about 10 minutes. It doesn't die after that.
My question is, how do I find out which number cluster the car originally came with? The K10042 or the K9800?
The cluster in it right now is a K10042.
Thanks!!
Greg

Oh... Ok, apparently sedans are K10042. I don't think I have the right cluster now so I don't have anything to compare so I make sure I get the right cluster...

 

different car, different problem (even if similar), please start a new thread.