CCKen

Open this link.


https://www.cherokeeforum.com/g/album/3212734


There are photos of the grounds in the engine bay. Some won't apply to the 2000. G101, for example, shows a ignition coil at G101. Of course your XJ won't have a coil, but the two ground studs are there.


To enlarge the pics click on them, and again if required.

Jay Hyland

Attached herewith is the video from earlier today from the clerk at Advanced Auto

Jay Hyland

Hear are pictures from my "ground-cleaning" the I have done.

I removed two posts from the right side of the engine and took a dremmel wire brush (no sandpaper) to the nuts, bolts and both sides of the terminal connectors.

I removed the rear ground strap from the engine bolt at the rear head and took a dremmel wire brush to the nut from the engine block and the bolt going to the firewall and to both sides of the terminal ends. I was unable to get the rear nut off of the head where the grounding strap sits on, however I took a small toothbrush sized wire brush to the bolt/nut assembly and cleaned, then Brakleen and repeated the process three times till it was relatively shiny.

I did NOT clean the grounding cable that comes out of the battery negative terminal and attaches to the inner fender. I could not get that damn thing off and I am sure that any more torque I apply will break the head. I have attached pictures of the front and back of this bolt. She is really in there. I am wondering if I could wire in a redundant grounding strap from the negative battery terminal to the body.

Is there any use in removing the PCM and cleaning that and re-securing it? And if so, is there a proper method?

Thanks in advance

CCKen

G100 (Battery (-) to fender) is a critical ground. Try to get that bolt out. If you snap the head off just go in the wheel well (your pic) and turn the bolt stub out using a small pipe wrench or vice grips. The bolt is 8mm.


No need to mess with the PCM.

Jay Hyland

I had a sneaking suspicion that you'd say that so I doused it with WD-40 before I went to bed and then again in the middle of the night. Despite dislodging the metal backing from the fender, it came out in one piece.

I wire-brushed both sides of the fender, the bolt and both sides of the terminal end. I also decided to increase the ground foot-print by adding a 1/2 x 3" mending strip plate between two additional fender washers from the negative terminal fender ground to the bottom mounting bracket screw for the cruise control unit (picture attached)

Furthermore, I added a redundant braided grounding strap from the right (left if looking at the engine) rear-most valve cover bolt to the evap (solenoid?) mount which I also cleaned with a wire brush.

Notwithstanding, after performing these repairs the condition is still present. Now, one thing that stands out is that the issue ("no bus", check engine, airbag and dead gauges) is immediately present whereas before it would take a bit of time to surface.

CCKen

Good work on the grounds.




Next step is to see what the CCD Bus is doing.


Do you have a quality manual ranging digital multimeter?


You will need one for these tests.


Refer to the CCD Bus schematic below.


First, determine if one of the termination resistors is out (usually the instrument cluster causes the problem).


1. Remove the battery negative post connector.


2. Set your meter to read resistance (200 Ohm Scale).


3. On the DLC, touch pin cavities 3 and 11 with the meter probes. You should see 60 Ohms. If you see 120 Ohms one of the termination resistors is out of the circuit. I doubt that it would be the PCM otherwise the engine may not run. Suspect the instrument cluster. If the resistance was 60 Ohms do the voltage checks below.


4. Reconnect the battery.


5. Set your meter to the 20 Volt/DC scale.


6. Turn the ignition switch to RUN/ON - do not start the engine.


7. Touch DLC pin cavity 3 with the meter (+) probe and pin cavity 4 and/or 5 with the (-) probe - you should see around 2.5 volts. Do it again only touch pin cavity 11 (+) probe. Again you should see around 2.5 volts. If you don't see the 2.5 volts refer to the schematic for the limits.


If the voltage reading are way out of spec the protocol is to start disconnecting the modules shown on the schematic until the voltages return back to spec. You cannot disconnect the PCM or instrument cluster.

Jay Hyland

Thanks a bunch...

... I am on it. Gimme a few

Jay Hyland

NOTE I have a Soundwire 21010N which is fully automatic. I am not, at least to my knowledge, able to manually program this meter - or atlas the manual inputs are limited. Notwithstanding, I believe it produced the proper results

OK...

With the negative terminal off, I am getting 060.2/3 ohms (Pictures Attached)

With the battery connected and the ignition on I am getting (Pictures Attached):
• 2.438 (+) #3 (-) #4
• 2.436 (+) #3 (-) #5
• 2.415 (+) #11 (-) #4
• 2.417 (+) #11 (-) #5

Does this mean a cluster? If so, should I repair or replace?

Also, can I apply some sort of coating of the bare metal pieces to avoid oxidation or will this degrade the ground?

CCKen

Those numbers look good.


60 Ohms means both termination resistors are on line. That's good.


The 2.4X voltage reading are within spec. That's good.


This is a long shot but check it anyway:

Jay Hyland

Here is what I have...

Key not in ignition switch:
• DOME AND COURTESY LIGHTS DO WORK

Key in ignition switch - Driver's door open:
• KEY MINDER CHIME DOES WORK/CHIME

Key to ACC:
• RADIO AND LIGHT DO WORK

Key to RUN:
• INSTRUMENT CLUSTER ADVISORY LIGHTS (CHRISTMAS TREE TEST) DO NOT ALL COME ON.

• NO ODOMETER - although the odometer may display at first start up, it will eventually pop a "no bus" fault

• NO FUEL QUANTITY OR VOLTMETER READINGS - although I notice a twitch in the voltmeter upon power up, just enough to lift if from full tilt, but thats it.

• NO OIL PRESSURE INDICATOR BUMP - I am not sure what "bump" means

• IF ENGINE HAS BEEN RUNNING THERE IS NO COOLANT TEMPERATURE INDICATION - although when the issue ("no bus", check engine, airbag, dead gauges) would arise when driving the RPM, Speedometer, fuel and Voltmeter would die immediately whereas the oil pressure and temperature would die slowly. If I shut the car off and restarted all gauges would remain dead.

Instrument Cluster Actuator Test:
•
Start Engine:
• NO INDICATORS
• RADIO AND RADIO LIGHTS WORK FINE


In reading this you'd think that it was #9 fuse as per your list, however I have checked all of the fuses and all are fine.

CCKen

It's time to have the code(s) read again. If a parts store code reader can't find a code take it to the dealer and have them put their DRB III diagnostic tool on it.


Edit: That Airbag light on may be the key to it.

Jay Hyland

Ugh... OK.

I am en route now and I'll let you know

Jay Hyland

I just came back and still they found no codes. The technician advised me that if he had to venture to guess, he would start with a cluster.

Your thoughts?

I took the cluster out and wiggled each wire two both connectors. I ensured they were firmly seated. I fired her up and all was working again.... then 5 minutes later the airbag light and speed and tach went dead. the other 4 gauges worked until I shut the vehicle off and restarted. Considering this, I am wondering if I have a weak solder on the cluster board. I was able to solder the master window switch leads that had broken solder points to a successful fix, maybe I could do the same here.

Your suspicion was the Airbag... praytell.

What about, for grins and giggles, I check the dash grounds?

Jay Hyland

CCKen??

sikkev

If you haven't already, go to the cpm on the left side of the engine bay and disconnect the middle connector and turn your ignition on (not to start) if your gauges come up, the cpm may very well be the problem. Or the connection to the cpm may just be a little corroded.