Engine/Transmission (1998.5 - 2002) Instrument Cluster INOP - "No Bus" Message Displayed on Odo.

[Hollywud]

Hello All...



Didn't have such a good Monday morning yesterday. In a rush to get to work, I ran out, jumped into my truck, started the engine and watched the oil pressure gage do nothing. The truck ran fine (i. e. no crazy noises) but, I shut her down after running and waiting with great anticipation for 20 seconds or so. I quickly looked under the truck for a lake of oil or something and found no smoking gun. Tried starting the truck again but watched the gages more closely this time... upon turning the key to the run position (i. e. wait to start light position), I did see the oil pressure gage needle move ever so slightly (so I don't think it's a fuse)... I fired the engine again... same deal no needle indication. This time I did notice that my volt gage needle was also resting with no indication.



Had no time to diagnose anything... . had to jump into another vehicle to get to work. I changed my oil on Friday night... checked the drain plug / filter a million times for leaks... drove the truck for 3 hours on Saturday with no issues at all... . parked it Saturday night and all day Sunday. Weather has been beautiful in the Northeast so, I can't think that rain water may have shorted anything out.



When I arrived home yesterday, I started diagnosing. First I tried restarting to see if the gremlins left... nope. However this time I was much more attentive of the cluster... noticed that all the gages weren't reading... on/off indicators were working... odometer flashed 2-3 times until finally reading "no Bus. " I'm definitely relieved that it isn't the Cummins but now I'm chasing electrons. I started trouble shooting per the manual but, am baffled by one step:



Check the fused B(+) fuse in the junction block.



OK, I know where the junction block is but, where the heck is the "fused B(+) fuse" located???



Anyone have the same problem?



Thanks for the help in advance...

 

[Gary - K7GLD]

Second "no buss" problem to crop up here in last day or so...



Check grounds, and connectors at PCM and ECM - that's where the "buss" lives...

 

[AggieJustin]

Check the connector under the dash, down next to the emergency brake. This is the connector that goes into the cluster. Make sure you've got a good connection here, otherwise you'll pick up the 'No bus' condition.

 

[justinp20012500]

No buss means the communication has been lost or disrupted from the cluter to the PCM.



3 out of 5 times its the PCM, the other two its the cluster. Niether one are cheap.



If I remeber correctly you can see the problem by using a DRB.



I would unplug and clean/grease the connectors at the pcm. (On the fire wall directly behind the air box)



Is you cluster going crazy??? Thats usually a good sign.

 

[Hollywud]

Thanks for all the tips so far!!! I'm leaving work shortly and will go home and continue diagnosing. I will try removing the cluster, applying dielectric grease, and reinstalling first... seems to have helped some and that's the only part of the system that I've touched in the recent past (removed to polish the clear plastic of the cluster). I'll look at all else after.



Stupid question... Would it be fruitless to disconnect both batteries, let it sit for a few minutes disconnected, and reconnect? Thinking that I might reset something in the process. Thoughts...



Also to answer one question, my gages are totally dead (other than a slight bump upon turning the key to the on position and they pass the self-test).

 

[P Mcgill]

instrument cluster inop

try under the hood on the drivers side,the main fuse box,grab the main wires and shake them and see if everything comes on. do this with the motor running. thier is a plastic plug that holds down the wires and it comes loose. hope this helps?

 

[Gary - K7GLD]

It's ALWAYS a good idea to disconnect the batteries while messing around with system plugs...

 

[CRead]

Had that problem about a year and half ago. I was the gauge cluster. Had dodge do the work, to busy to do anything. It was about $850 for everything. The bad part was I had to wait 3 to 5 days for the part. Dodge has to program the mileage in it. And the truck had to sit till the part was installed. :{ Had that problem about 6 months before this one and the gauges came back on a mile away from the stealership still took it in and had them check everything they said they tightened some connectors and did a TSB on something in there.

 

[Hollywud]

Ok, I used a scan tool to read the DTC's set and here's what I got: P1698. The scan tool says that it means "No Transmission Bus Communication. " Could someone help interpret this code?... What do you think it's pointing to?



I'm skeptical that it's the cluster since, all functions work perfectly when I run the self diagnostic check. Maybe I just don't understand the circuitry thru the cluster. I've checked all other connections & grounds and all seems fine.



Again, thanks for the help received thus far and for future posts...

 

[Gary - K7GLD]

The logical choice is to closely check all connections between the transmission and the computer...

 

[Hollywud]

But it's a manual trans... the only connections I can think of off the top of my head are for speed & reverse light.

 

[Gary - K7GLD]

But it's a manual trans... the only connections I can think of off the top of my head are for speed & reverse light.

UH-ohhh - that doesn't sound good - sounds like an ECM/PCM gone bad...

 

[ACoyle]

There is a TSB out for this problem on the '99's



http://dodgeram.info/tsb/2000/08-05-00.htm

 

[JHayden]

I had same problem with my '00. Had no driveability problems. The "no bus" showed on the readout and there were multiple error codes with scan tool and using the cluster diagnostics. I ended up taking out the PCM behind the airbox and using a wire wheel to clean up the the mounting tabs (on the pcm) / bolts / area on firewall / ground wire eyelets. Put it back together and been working fine for months. Expect to remove and use dielectric grease on all affected areas before winter. Probably be a good idea to clean and lube battery terminals / starter wires / alternator wires if you have the other grounding problems. I know two people ('98. 5 & '99) that have had the starter cables replaced.



-John



'00 SRW 4" & 275's

 

[Hollywud]

My issue was with the right side connector behind the instrument cluster. Dielectric grease helped but I wound up replacing the connector. Been working fine since replacement...

 

[ChrisOlson]

JUST like Hollywud, my wifes 2001 durango started having all sorts of electrial trouble no bus in the cluster gauges dead, they told her it was the instrument cluster then the trans control module. then the PCM they really had no idea, the durango was down for 3 weeks still no fix when we got it back it would just stop running then act like a dead battery and of course I was out of town, I called the dealer told them to change the battery they said the battery was good they did not change the battery kept having electrical problems got so sick of the crap I had the wife trade the thing in with a different dealer for her jeep liberty he knew about the elec. problems and what did he do he changed the battery and all problems stopped. The new owners have had no problems at all and love the durango. I am fighting with DC right now about the not needed repairs. HoweverAll is well now she likes her liberty better than the durango and a happy wife is a happy house. dont even get me started on the harley battery!!!!



And on a side note I would like to ad something here Dielectric grease on electrical connections. the random house dictionary definition of "Dielectric" A non conducting susbstance; insulator. as An Maritime Engineer we deal with Dielectric connections because we do not want to conduct electricty thru things I would humbly suggest using a conducting lubricant on those connections. just my 2 cents worth.



I am glad you found the problem Hollywud

 

[nps]

Conduction occurs through the metal to metal contact between the connector sockets and pins. The dielectric grease acts as a sealant to keep moisture (hence corrosion) out after reestablishing a new contact by reseating the connector.



You DO NOT want conducting grease because it would short all the pins to each other and nothing would work.

 

[ChrisOlson]

you are absolutly correct I agree completly conduction does occur thru metal to metal contact personally I would use nothing on connector sockets and pins and i apologize if i implied that, what I meant was when I was talking about grease I was making reference to the grounding points on the chassis I was remiss in explaning what I really wanted to say. once again I apologize for any confusion

 

[ToolManDoug]

"no bus" Abs on,engine lite on, seatbelt lite on,brake lite on and no gauges

Hey guys, after reading all the threads I can possibly read and reading everthing in the service manual about this problem I just pulled the instrument cluster out, slipped some thin stripps of cardboard behind the docking pin recepticles to space the recepticles closer to the cluster, greased up both sides real well with diaelectric grease and reinstalled the cluster,problem has not come back since and that was a week ago.



01 2500 4wd auto

 

[Hollywud]

Here's what wound up happening to mine...



I made an appointment with the "man" late September. As I was driving over, I heard a "bing" and looked down at a fully functional instrument cluster. I decided to have them look at it anyway... even though it seemed fine after multiple start cycles. They diagnosed the right hand vehicle-side connector to be the culprit and to remove & replace. I told them to hold off and I figured I'd drive the truck and see if it comes back (during trouble shooting I applied dielectric grease and thought that driving vibs may have worked it into all the right place). Anyhow, I'm still driving the truck with zero issues... 2-months are history (probably just jinxed myself).



jon