Going insane with no bus code

I have now been after this problem since the summer and i've exhausted every lead i can possibly think of.

Over the summer I did a 5-90 upgraded battery kit and after i did that this is when the problem has surface.

When I start up the jeep the following things happen
I get volts, gas guage and temp gauge to work.
My check engine and airbag lights are on and i also have a no bus in the odometer reading area
And my tach, and oil pressure and I believe speedo all dont work.
Also if you put it in drive and try to drive it sounds like your attached to a building, im guessing because the tranny isn't shifting b/c its in 3rd. But if i manually put it in 1 it takes off no problem.

I have gotten the FSM and i've exhausted every lead in that book. I went to the guage cluster portion and did EVERY step they said, and everything check out ok time and time again. I've probably done it about 5 times just to be sure.

Then i thought maybe it was the ecu, so I replaced that, still a no go.

Thought it could be the guage cluster itself, had another one laying around that wasn't it either.

Then i started to look at the pinouts of the ecu. Saw theres a ccd bus pin on the ecu. I follow that through the wiring diagram which leads you to both the data link and the guage cluster. Checked that for continuity that checked out.

I don't know what else to do. I havn't drive my jeep in a year and my wrx is on its last leg. If anyone has ANY ideas please share.

Thanks
Matt

maybe try PMing 5-90 and see if he's got any suggestions?

Also, the shifting thing sounds like a seperate problem, I forget what exactly it's called/what to do or whatever, I'm no auto guru by any means, but a friend of mine's XJ had the same problem with the tranny, and none of the other symptoms you've listed, which would lead me to venture a guess that it's an independent situation?

Sorry I can't help with the electrical bit, I think anything I could have suggested you've already tried...

Good Luck,

matt6669 said:

I have now been after this problem since the summer and i've exhausted every lead i can possibly think of.

Over the summer I did a 5-90 upgraded battery kit and after i did that this is when the problem has surface.

When I start up the jeep the following things happen
I get volts, gas guage and temp gauge to work.
My check engine and airbag lights are on and i also have a no bus in the odometer reading area
And my tach, and oil pressure and I believe speedo all dont work.
Also if you put it in drive and try to drive it sounds like your attached to a building, im guessing because the tranny isn't shifting b/c its in 3rd. But if i manually put it in 1 it takes off no problem.

I have gotten the FSM and i've exhausted every lead in that book. I went to the guage cluster portion and did EVERY step they said, and everything check out ok time and time again. I've probably done it about 5 times just to be sure.

Then i thought maybe it was the ecu, so I replaced that, still a no go.

Thought it could be the guage cluster itself, had another one laying around that wasn't it either.

Then i started to look at the pinouts of the ecu. Saw theres a ccd bus pin on the ecu. I follow that through the wiring diagram which leads you to both the data link and the guage cluster. Checked that for continuity that checked out.

I don't know what else to do. I havn't drive my jeep in a year and my wrx is on its last leg. If anyone has ANY ideas please share.

Thanks
Matt

Click to expand...

What year would help alot here, Matt?

probably 97+ before that there was no bus code in the odometer, as it was mechical

Sounds like a bad cluster or cluster connection. You need to find out if the data link can talk to a scan tool. Get back to me if you find out anymore. Also check fuse for data link power.

This could also be because the trans puter is not comunicating with engine puter.

Your Bus problem is likely throwing the tranny into limp-in mode, causing it to hang in 3rd. Find that and you prob. fix the trans at the same time. I'm not familiar with the upgrade you're talking about, but I would go back over everything you did with a fine-toothed comb. Look for any grounds you may have inadvertently loosened or removed that didn't get re-connected, it sounds to me like a grounding problem. Not sure how familiar you are with the bus stuff, but basicly all the main control modules like trans, engine, airbag and ABS are on a bus circuit (ccd bus) where they all talk to each other. If any module goes down it can take down the whole bus. A little difficult to diagnose without a scan tool. More details on the upgrade would help.

His profile says he has a 98.

Try this out for a possible soloution. You may not need to replace the connector, but it is probably the best way to do it. Some people have just cleaned the connector and put a slight twist in the pins in the cluster itself.


TSB NO: 08-15-99
SUBJECT: Erratic, Intermittent Cluster Operation/Intermittent Air Bag Warning light.
DATE: May 21, 1999

OVERVIEW:
This bulletin involves installing a repair harness containing a revised instrument cluster connector.

SYMPTOM/CONDITION:
Some vehicles may exhibit an intermittent illumination of the air bag warning light or an intermittent tachometer or speedometer drop out. An Airbag Electronic Control Module (AECM) fault code -"No Cluster CCD BUS " message will be present.

DIAGNOSIS:
Using the DRB III®, read and record all active and stored fault codes in the AECM. This condition is caused by minor oxidation of the BUS circuit terminals at the instrument cluster connector. Electrical terminals will show signs of oxidation, which will appear as darkened lines or marks on the cluster male terminals. These often appear as gray or black marks rather than the appearance of oxidation or corrosion usually associated with higher current carrying circuits. This condition will set a "NO CLUSTER CCD BUS" message. The fault code will usually be stored and not active. THIS TECHNICAL SERVICE BULLETIN WILL NOT ADDRESS FUEL OR OIL PRESSURE GAUGE ISSUES. If this fault code is present, either active or stored perform the Repair Procedure.

PARTS REQUIRED:
Qty Part No. Description
1 05016261AA Cluster Connector Patch Harness
1 04856975 Electric Contact Cleaner
2 04778570 Heat Shrink Tubing

Disconnect the negative battery cable.
Remove the instrument cluster using the procedures outlined in the appropriate servicemanual.
Inspect the male terminals of pins 1 & 2 on the instrument cluster connector labeled CNB (See Figure 1). The oxidation will appear as gray or black lines or marks on the terminals. If any signs of oxidation are present, remove them by gently scraping the terminals with a small flat bladed screw driver until the oxidation is gone. Use of a magnifying glass may be helpful (See Figure 2). Use caution when performing this operation. Do not apply excessive force to the terminals to avoid bending them or damaging the cluster or terminals. Do not use a sharp tool, knife or sand paper, which could remove the protective plating from the terminals. Do not use any cleaner other than p/n 04856975. Other chemical cleaners could damage the instrument cluster.
Clean the male terminals with Electrical Contact cleaner, p/n 04856975. Apply the cleaner sparingly holding the cluster with the connector facing down to avoid excessive amount of cleaner from entering the cluster.
Remove the green cluster connector from the bracket.
Using wire cutters, remove the instrument cluster harness connector from the harness. Remove only the connector containing the BUS circuit (See Figure 1). This connector is labeled CBA on the cluster. Cut the wires as close to the insulator as possible.
The new connector must be soldered onto the harness. This operation requires a technician who is skilled at soldering to avoid a cold solder joint. Position the harness and align the wires with the patch harness, matching the color codes match the main wire colors.
NOTE: THE XJ INSTRUMENT PANEL CONTAINS ONE MORE CIRCUIT IN THIS CONNECTOR THAN THE TJ. CUT THE UNUSED WIRE CLOSE TO THE CONNECTOR ON TJ MODELS.

Stagger cut the main harness and patch harness wires so that the solder joints will be 1/2 inch apart. Remove 1/2 inch of insulation from the wires. The new harness will have a dark blue with no tracer. This will mate with a dark blue wire with a green tracer on TJ and with a dark blue wire with a white tracer on XJ.
Slide a piece of heat shrink tubing over the wires and twist the wires together for each respective circuit.
Solder each circuit using rosin core solder. Be sure to heat the wire enough to allow the solder to melt when it comes in contact with wire. Do not use acid core solder.
Position the heat shrink tubing over the solder joints and shrink the tubing using a heat gun.
Install the connector to the bracket.
Install the instrument cluster.
Connect the battery cable.
Verify correct operation of the cluster.

I've heard about that TSB and I've been thinking about replacing it but I'm not sure if thats the problem. I checked those connections and they all look fine. I have a feeling it has to do with that upgraded battery harness.

Yes the truck is a 98 I forgot to mention that. I also only have one of those crappy orange scanners and it says it can't complete the diagnostic test, and then it gave me a bunch of 02 codes and another code i can't remember. I'll be back at the shop tomorrow and I'll grab those codes as well. Also I checked the fused b+ at the data link and its getting power so I know thats ok. I checked the ground at the cluster I know thats ok. I've swapped clusters and ecu's so i know thats ok.

I'm almost to the point where im gonna go source the wires that I took out to do the upgraded battery wires and put them in, and see if it fixes the problem because this is crazy.

Thanks so much for the posts guys, it does give me some things to look at as well.

I did contact 5-90 and he was very helpful with as much as he could help me. He said he never heard of that happening told me a couple things to check but nothing worked.

You need to get a GOOD scan tool & see if you can talk to the trans? Or take it to a shop that can. A trans issue WILL cause your engine to act funky & set the MIL light.

yeah getting my hands on a good scanner isn't the easiest thing to come by these days. I might have to find a shop that would hook me up but i don't even know any reputable shops nearby that I could bring my truck too.
BUHH

anyway to check if something happened to the pdc without a scanner??

no one else come up with anything cause i know im stumped

I am having this same issue!! I have had intermittent no bus/no guages for a weeks now. I can hardly even drive it now
I realize, after reading your problem, that I replaced the engine to firewall ground about 2 months ago. The ground is secured at both ends I believe. How could modified grounds contribute to our problems?

BTW, I did tweak all my pins and put di-grease on them and it still didn't fix it.

it's fairly common for the clusters themselves to have an internal fault that creates an open circuit in the pci bus communication line. I've replaced a couple of them. First i would do the TSB, if that doesn't do it, i'de replace the cluster. the only problem with that is i'm sure they aren't cheap and i don't think it's replacable with a junkyard part, i could be wrong tho.

it also wouldn't hurt... if before you replaced the cluster, you checked resistance in the bus circuit between the cluster, and pcm as well as tcm to pcm. there could be an open in one of those circuits.

already checked resistance from the bus + pin on cluster harness to bus + pin on ecu harness and its perfectly fine. Come to think of it i don't think I checked the negative.

I've also swapped out clusters and thats not it either.

I've also checked the grounds 20 times and that all checked out as well

I have a couple more tricks up my sleeve im going to try this weekend but im not holding my breathe. I've been trying to locate a scanner to no avail it sucks

Try unplugging the Crank Postion Sensor and see if your gauges start to work again.
The NO BUS should go away too.

The ECM needs an 8 volt reference to communicate through the BUS to operate the cluster. If any sensor shorts, the ECM fails to process the signal and lights the NO BUS warning.

Good luck.

AHHHHHH now that is an insightful piece of information that I would of NEVER thought of. I am going to try that first thing saturday morning. Now if I do this and all is well again, just replace said sensor and I should be good to go??

Possibly. You may have to check other sensors as well.

One at a time, unplug each sensor and turn the key on, and await the desired results. Replace the offending sensor.

You checked all fuses under the hood aready right?

yeah i checked all the fuses and every single wire i can possibly think of as well.