Intermittent "no bus" issue has stranded me again.

Big Montana · **Posted:** Fri Jan 10, 2014 5:52 pm

It's getting worse every day. I was stranded over a month ago when my jeep wouldn't receive a signal from my key to even unlock the doors. Opening the door manually triggered the alarm and turning the engine on only resulted in a stall two seconds later when the security key wasn't transmitted. I had a thread about how I was towed away to a dealer because of apparent broken wires in five spots that shorted out my computer system. They fixed it but since then, at random times during a drive, my jeep's sensor/dash lights will ding on and off a few or all at the same time. Sometimes the analoge gauges will shut off completely and the trip tick number will be replaced by the words "no bus". I just recently noticed that during these fits, the volume and channel buttons on the back of the steering wheel fail to work too. The cruise does work though. Go figure. The radio is unaffected as well.

This is bad enough, but if the engine isn't running when it decided to shut off the "bus" system, I can't get the car to stay running. It doesn't get the key code I guess. I've removed the silver computer just in front and below the battery and dried it and cleaned the connections for the plug. I wrapped it in three plastic bags and reinstalled it. GDE had recommended I clean this module as it could be causing the "can bus" system to fail. It doesn't seem to have worked. In fact, I seem to have made It mad.
EDIT: that's not a criticism of GDE. They are on the right track because during today's event, I could shake and wiggle the wires and get it to start again for the two second span. Once it stalls, it won't turn over again until I shake the wires and computer.

Here are my codes:
U0146 network "current fault"
U1421 network "current fault"
P0513 power train incorrect immobilized key "immobilized pending SAE J1930 approval
P1001 powertrain
B2TAE Body

Any help would be nice. I'm currently stranded at my in-laws

Big Montana · **Posted:** Fri Jan 10, 2014 6:10 pm

This situation always seems to happen when it's wet. Even with the below zero temps, I noticed that the silver computer unit I took out was wet and surrounded with snow. Today the temps got above freezing and the roads are wet.

Is that computer grounded to the frame with its housing? I ask because the bolt holes at the bottom were rusted out. I only had to remove the two top bolts from the black "L-shaped" bracket to get it out. I also noticed just now while wiggling the "L-shaped" bracket hat it's about to break in half due to the amount of rust. This whole thing must be a ground issue right? If it were the computer unit, wouldn't it be broken all of the time?

I pushed it into the garage (my mother-in-law's spot) and I'll try to dry it out. That has worked in the past.

I still need to figure out what to do. I also need to up load the video. It's been a while and I can't remember how to do it.

racertracer · **Posted:** Fri Jan 10, 2014 8:50 pm

Here are my suggestions.

1. Make sure your battery is fully charged. Sometimes a weak battery will do weird things to the system, so procure a small computer controlled trickle charger and allow it to fully charge the battery.

2. Check the location of wires that were supposedly fixed by the dealer, wiggle them while the vehicle is running and see if you get a bad response.

3. Disconnect the ECM and the battery for a few minutes and allow the system to reset.

See what happens.

My battery was my problem and I have a 2 year old Sears P1 battery, the trickle charger did the trick.

Big Montana · **Posted:** Fri Jan 10, 2014 8:58 pm

I will thanks. I nev r thought of the battery because it's also a 2 year old diehard P1. You know... I've been complaining about a squeeky pulley somewhere... I wonder if my autozone alternator is the culprit and it's leaving my battery under charged. That would be amazing. Its been starting okay though. Other than the cold, it has turned over strong.

racertracer · **Posted:** Fri Jan 10, 2014 9:11 pm

Well, mine turned over just fine but it didn't start it.

Remember that the P1 cannot be charged with a conventional old style charger, if you do, it may ruin it. The new computer controlled battery chargers are meant to be used instead.

I picked up an inexpensive computer controlled trickle charger at Wally world and it did the trick.

The alternator decoupler could be faulty, check for rust by removing the plastic black cover in front of it. Mine went out in October and it too was purchased the previous year, it came pre-attached to the alternator.

The whole unit was under warranty from Advance Auto Parts and I got a brand new one in return.

Big Montana · **Posted:** Fri Jan 10, 2014 9:19 pm

I didn't know that about the battery. Can they still be jumped by another car? I've never had to charge it before, but that's a tip I shall remember.

Big Montana · **Posted:** Fri Jan 10, 2014 9:21 pm

You mention that you had similar problems. Have you ever had the milage numbers replaced with "no bus"

racertracer · **Posted:** Fri Jan 10, 2014 9:23 pm

There is a proper way to jump start a Sears P1 and maybe a member that knows more about batteries can give us some insight.

Big Montana wrote:

You mention that you had similar problems. Have you ever had the milage numbers replaced with "no bus"

No, I never had the words "No Bus" pop up on the odometer reader instead of the odometer numbers, that must have been a very strange sight to see.

Unplug that ECM for about 5 minutes or more and allow it to reset.

I've noticed another strange computer related weirdness. Before my transmission was replaced by the dealer, the CRD would not start sometimes unless the connector to the TCM was detached for a while first.

Verbal_CRD · **Joined:** Wed Jan 09, 2013 8:23 pm **Posts:** 46

I've seen similar issues caused by the TIPM. Not fun or cheap to replace.

Sent from my SAMSUNG-SGH-I747 using Tapatalk

Big Montana · **Posted:** Sat Jan 11, 2014 1:23 am

Could you please tell me more about the TIPM? What's that?

Billwill · **Posted:** Sat Jan 11, 2014 4:24 am

I had some funnies with my ECM which cleared up once I added a seperate ground from the ECM casing to a clean chassis point so that is worth a try.

I remember recently Keith suggesting that the "Bus Gateway Module" or something similar to that sits behind the left-front wheel ie. driver's side... and gets water splashed up against it which causes this problem....not the ECM!
My 2002 Export CRD does not have this Gateway...I will have a look at the 2005 CRD documentation to see if I can find it but poke around that area and see if you can find this module! :wink:

Edit to add:

This is called the "Front Control Module".

It sits mounted vertically on the LHS, under the fuse box under the hood, to the left of the radiator...I would think it is about 4 inches square.
have a look at this and see if it has gotten wet and maybe needs some proper water-proofing! :wink:

Big Montana · **Posted:** Sat Jan 11, 2014 9:54 am

Billwill wrote:

I had some funnies with my ECM which cleared up once I added a seperate ground from the ECM casing to a clean chassis point so that is worth a try.

I remember recently Keith suggesting that the "Bus Gateway Module" or something similar to that sits behind the left-front wheel ie. driver's side... and gets water splashed up against it which causes this problem....not the ECM!
My 2002 Export CRD does not have this Gateway...I will have a look at the 2005 CRD documentation to see if I can find it but poke around that area and see if you can find this module! :wink:

Thanks Billwill. This is the module that Keith had me work on. I removed it completely and cleaned and dried it. It was -10 F that day. I had so much fun doing it. The bottom of the silver module is corroded and the two screw holes at the bottom were mostly gone and dissolved.

Billwill wrote:

Edit to add:

This is called the "Front Control Module".

It sits mounted vertically on the LHS, under the fuse box under the hood, to the left of the radiator...I would think it is about 4 inches square.
have a look at this and see if it has gotten wet and maybe needs some proper water-proofing! :wink:

You've got me thinking here. I wrapped the module in three plastic bags and put three zip ties around the opening as the plug passes through. When I reinstalled the module, I punched two little holes in the bags for the bolt holes at the top and screwed it in. As I said, this only seems to have made it worse. I'm wondering if it's because the module is no longer touching metal on the frame.

Does anyone know if this module needs to be grounded to the frame? I guess I can find out by taking it all apart again and running a ground wire from inside the bag.

Big Montana · **Posted:** Sat Jan 11, 2014 2:13 pm

Well I put a ground wire in from the housing of the bus control unit to the frame. I got it started but it still pops all of the lights on and off. The "no bus" light seems to have gone away. Everything is soaking wet here, so I don't know what is going on in that engine bay. I still don't know if it's a ground issue or an actual computer module breaking down.

I'm seriously contemplating a trip to a dealer. I'm either going to shoot for a trade or see if a tech can track down the problem.

Mike92104 · **Posted:** Sat Jan 11, 2014 8:07 pm

I wonder if the gas models use the same part. Maybe you just need one from a less rust prone area. My thoughts are that it is a grounding issue of some sort. If the chassis of the box was corroded, I wonder if it is not being grounded somewhere inside the box.

Mike

Big Montana · **Posted:** Sat Jan 11, 2014 8:25 pm

Mike92104 wrote:

I wonder if the gas models use the same part. Maybe you just need one from a less rust prone area. My thoughts are that it is a grounding issue of some sort. If the chassis of the box was corroded, I wonder if it is not being grounded somewhere inside the box.

Mike

This is a mess. I never left the driveway and I parked it in the garage out of the rain. It won't start again. I wonder if you're right that the whole unit is messed up. I really don't know how to diagnose electronic faults. I wonder if there could be a specialist in my area of her than the dealer? They told me flat out fhey don't like worki g on CRDs. At least they were honest.

racertracer · **Posted:** Sat Jan 11, 2014 8:31 pm

Big,

Have you disconnected the ECM and reconnected it again?

Have you fully charged the battery?

Big Montana · **Posted:** Sat Jan 11, 2014 9:05 pm

Yes on the ecu but no on the battery. I don't have a charger. I get nothing now when I turn the key other than no bus on the dash. Something is killing my bus. Help me GDE, you're my only hope.

Has anyone replaced or had to replace their forwarx bus control module?

Big Montana · **Posted:** Sat Jan 11, 2014 9:17 pm

I left the key in the on position while I wiggled a bunch of wires behind the battery and I heard a ding from inside the cab. I got the bus back and I was able to start the jeep. It stayed running. I wish I knew which wire. The abs, airbag, engine, and red security lights are on. So is the passenger airbag light. I wiggled more wires and lost the bus again. Ahhhhhhhhh!

racertracer · **Posted:** Sat Jan 11, 2014 9:31 pm

Well now you're on the right track...... this process will be slow but sure.

Big Montana · **Posted:** Sat Jan 11, 2014 11:54 pm

Oh for crying out loud. I got on the road to leave the in-laws, and the Jeep went into limp mode. The lights were all going crazy, but this time the glow plug light was going on too. That was a new one. I decided to avoid the future tow charge, so I drove right to the local dealer. I was going to leave it for Monday.

What happened next is so crazy it's funny. I left the engine running while I transferred my gear to my wife's van. I shut the driver's door for a moment and the doors automatically locked before my eyes. My spare key was at home ten miles away! I thought about breaking a window, I thought about lighting a fire, I thought about just leaving it running and going home to have a beer before I lost my mind, but I left it running and drove home to get the key.

It sits now out in the cold rain. I have no idea how expensive this is going to be. I think her days are numbered with me. Electronics is something I fear. I'm willing to try almost any repair, but I am very ill equipped for this.

Intermittent "no bus" issue has stranded me again.

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