Ok guys I know this has been covered hundreds of times but I just can't find the answer anywhere. Bought an 01 XJ a few months back with No Bus. Started by checking the gauge cluster smack dash, push on cluster, took cluster out and cleaned contacts, removed and cleaned every single ground on the Jeep. Ended up buying a new cluster, now this cluster does NOT display No Bus, still none of the gauges work odo is stuck, trip non operable. I do not have an overhead consol. Oddly when I first was looking into the issue I had voltage in the bus circuits both at the obd connector and at the rear cluster connections I tried again today and had 0. Almost done, my airbag light does not stay on like others have had, when running gauge self test everything works. Wondering what else I should check.

Any help is appreciated. Thanks in advance.

 

Forgot to mention it runs and drives like a dream, and of course checked all the fuses.

 

Check fuse #9 in the Junction Block fuse panel. It powers the instrument cluster.

 

Checked and replaced #9 and #16 they didn't appear bad but I replaced them just to be sure.

 

Well...did it fix it?

 

Sorry, no it did not.

 

Does it still run okay with the CCD Bus reading zero volts?


Should be around 2.5 volts at pin cav 3 and pin cav 11 using pin cav 4 and/or 5 as ground, and 60 Ohms between pin cavs 3 and 11


Are you going by this:

 

Ok I'm an idiot, the hold was on my multimeter last night hence the 0. Anyways I have very low voltage .02 between pins 3, 4, 5. Same when using pin 11. Checking OHMS I got .11. Seems way off and it's been a long time since I've done electrical so I've attached a photo of my OHM reading just in case my meter is set wrong.

 

Select 200 Ohm scale on your meter for the resistance reading, and 20 VDC for the voltage readings. If still very low voltage, select the 2 VDC scale.


The ignition switch does have to be in the ON/RUN position for the voltage readings (engine not running).


If you get more than 60 Ohms (like 120 Ohms) going from 3 to 11 there's a possibility the termination resistor in the instrument cluster is bad, same goes for the voltage readings, if they are too low the bias module may be bad. See the note in the chart above. The same thing can occur if the CCD Bus wiring is defective.

 

Previous readings were taken with the cluster out. This time round cluster is in. Voltage is up to 0.5v, and the ohm reading is 0.05. Not sure if it means anything but voltage is not constant it jumps between 0.48v and 0.5v.

Ohms are being checked with battery disconnected, just want to make sure there's nothing different about checking the bus.

 

Did you take the voltage readings with the ignition switch to ON/RUN (engine not running) and the meter set to 20 volts DC? And the resistance reading with the meter set to 200 Ohms?


If so .5 volts at pin cavs 3 and 11 and .05 ohms is not a good sign. The instrument cluster or the PCM termination resistors and/or the bias module in the instrument cluster if defective. Can't rule out bad CCD Bus wiring however.

 

Voltage was checked with the key in the Run position. Would you happen to know where the wires begin and end so I can check for continuity through them.

Sounds like if the wires are ok it's time for yet another cluster.

CCKen you really know your stuff and I appreciate all your help.

 

Actually the protocol when bad voltage readings are encountered is to start disconnecting modules on the CCD Bus one at a time to see if it makes a difference. Obviously you wouldn't disconnect the instrument cluster or the PCM, but start with the TCM, then the RKE.


See above chart for the respective modules.


I will dig up a diagram of the CCD Bus wiring so you can see what's going on.

 

Unplugged TCM, checked gauges, no change. Unplugged RKE and TCM at the same time, checked gauges, still dead.

 

Should I just continue unplugging everything associated with the CCD Bus and see if one of them will bring my gauges to life. Or at this point would we start to suspect cluster or wiring?