QuestionQUESTION: Hi
I havent goting to bottom yet, my 1999/300M but I dont trust mechanics here , you know they got that "I think so look", car still runs 10 minutes after all gages go O code PD 1687.
I changed cluster and had same problem, last elect mec told me computer(he thinks is not doing ground, told me get a computer
Im thinking in doing this myself next week Im a bit mechanical inclened, That pin 5 is it a 5 I can see or I need diagram?
Thanks for help, another thing a new computer is it plug and play?
ANSWER: Hi Hiram,
The plugs all have engraved numbers on them where the wires come in. The communication bus wire is on pin 5 of the green plug (violet/yellow wire) and it is connected to pin 13 of the gray plug at the body control module. That module is on the back side of the dash fuse box (they are attached together which you have to remove to get to. You open door and remove the end cap of the dash and remove the 2 screws that hold the lower underdash panel it in place, Then you remove the lower panel under the dash below it and disconnect the hood release cable and the deck lid switch. Then remove the knee blocker and under colume ducts. Then you should be able to take out the fuse box/bcm by removing its four mounting screws, and see the bcm's four plugs, and check that wire.
The trouble shoot for the 1687 does speak about checking the wires I described. If you can't find anything wrong with that it says to replace the pcm (computer). If you do that be sure you get one from the same year/engine/body as your vehicle. But I wonder about that because the wire first goes to the bcm and from there to the pcm and tcm. So I am wondering why not question the bcm as an issue? But if we follow the manual for that code it is the pcm (if not a wire) that is the fault. If you replace it, the vin and mileage need to be programmed and if you have the security key immobilizer that too has to be reprogrammed. So it is not plug and play unfortunately.
What happens when the fault occurs other than the cluster reading/gauges?
Roland
---------- FOLLOW-UP ----------
QUESTION: I had similar isue long time ago<i found the problem in a loos wire at brake pedal stop swich, this time at a trafic jam (over 45 minute) the gages went to cero and check engine came on, If car is stop for a long period isssue is gone , but after a 10 mkinute drive it does it againg. I just dont want to buy+pay instalation a a computer, and still have the issue on hand, I was told check solder in wires, had it done but after 30min (longer now) it still does it, and the other day it was going off/on ( check engine ) and sometimes car wont start thill I leave if park for 30 minutes or so, last I did was 3 weeks before I had installe fan motors from auto zone, car work fine after. Ill keep looking, last resort is to get rid off it...bUT I LOVE THIS CAR.
AnswerHi Hiram,
About the only other thing I can suggest is that when the gauges fail and all the rest happens, that you leave the key in the 'run' position and check fuse 14 (last one at the back of the fuse box, in the middle row) of the fuse box behind the dash. That fuse powers up one section of the body computer which I mentioned is involved in the communication system and so if that fuse has a crack in its wire that opens as the fuse is used, and then closes after the fuse cools off, that would explain the 30 minute time delay to recovery. Use a voltmeter to see whether it is actually showing 12V on both sides of the fuse with the key in the 'run' position and while the gauges aren't working. If not passing the 12V, then if you look closely inside the fuse you may see that it has a subtle crack in the wire.
Roland
PS If you would like to 'rate' me again, and offer a 'yes' for 'volunteer of the month', as you did earlier, I would appreciate that.
