Community Forums

DJJ · 09-11-2013, 05:27 PM

Left Santa Fe this am and temp gauge did not work so I stopped at the Albuquerque Freightliner on the way to Flagstaff AZ. They said next week before they would look at it but the computer should shut the motor down if it starts to over heat. Started the motor to leave and the oil pressure gauge did not work. Felt I probably had oil pressure as to big of a coincidence with the temp gauge not working first. Shut the motor down to be safe and started calling around town, know one could get to me until next week. For grins I turned the key on and the water temp gauge came up to temp so I started the motor and the oil gauge worked. The gauges worked the rest of today.

2003 Newmar Dutch Star Freightliner w/ Cat 3126B Eng.

Does anyone have any idea what would have caused this?

Thanks in advance, Jeff

Rook · 09-11-2013, 06:30 PM

I know.....GRIMLIMS!!!! ....smile. Rook

Rook · 09-11-2013, 06:32 PM

Seriously......GROUNDS (defective ones) can cause all kinds of weird problems, including what you have. Rook

FIRE UP · 09-11-2013, 06:52 PM

DJJ,
Freightliner gauge and dash systems are normally operated by computer. There are different versions of the computer that handles that duty. For instance, yours "should be" the version called the "VDC" or, Vehicle Data Computer. And, it's also known as the "System III". Ours, in an '04 Itasca Horizon 36GD with the 330 HP C-7 CAT, uses the version called the MMDC or, Multi-Module-Data-Computer.

Now, what all this means is, they (the controlling computers) receive data from multiple sources like the engine ECM, the trans ECM, the ABS module, and more. All that data travels along what's called a "J1939" data link to the controlling computer. Then, the controlling computer either converts it to digital or, analog and sends it to the dash and all the gauges.

Now, there's not only the signals being sent but, there's grounds for those dash and gauge systems too. Bad grounds can and have been, one of the most notorious problems of the automotive industry causing problems since the first car rolled off the assembly line.

Now, what does all this mean to you, you ask? Well, your gauges are fed through this data link system and, the controlling computers. Normally, more than just the two gauges you had trouble with go out which, is usually caused by " a bad ground" but not always. So, where to look for your problem, NOT A CLUE. But, this is just some information on how your system works. Connectors, which there are many along the backbone of he J1939 Data link can go bad, I know, I had one do it. And it caused a whole series of problems. Very difficult to locate causes of issues like you have.
Scott

Theberrys · 09-11-2013, 07:19 PM

Here is something to look at. I'm not sure what the symptoms are when this is needed but several folks have needed to do this rework.
https://skydrive.live.com/?cid=ae67f...59&app=WordPdf

Dick

Tony Lee · 09-11-2013, 07:42 PM

I had a problem where all the dash meters took turns at randomly not working. Stopping and starting the engine often fixed the problem - until next time.

Checked grounds with no improvement.

Finally the starter battery failed and was replaced - and dash instrument problem went away.

I think what was happening (over several months so the fault was subtle) was the battery was on the way out and because of the starter draw the battery dropped in voltage and took a few seconds to recover during the period that the gauges were all going through their initialisation sequence and this low voltage caused some of them to "stick" at zero or full deflection at random.
The new battery doesn't sag so the instrument panel starts up normally.

Hard to prove one way or another of course.

Rook · 09-11-2013, 07:54 PM

Quote:
"I think what was happening (over several months so the fault was subtle) was the battery was on the way out and because of the starter draw the battery dropped in voltage and took a few seconds to recover during the period that the gauges were all going through their initialisation sequence and this low voltage caused some of them to "stick" at zero or full deflection at random.
The new battery doesn't sag so the instrument panel starts up normally.

Hard to prove one way or another of course."

A bit "far-fetched", but makes sense to me......Rook

DJJ · 09-12-2013, 06:55 AM

Thanks for the advise and Fire Up thanks for taking the time to explain how the system works. I think your on the right path. Maybe 3 or 4 times this past month when at idle the ABS lite would come on and go out as soon as I started to drive down the road. Too many things starting to go on with the dash Gauges. I hope holds together for another month of travels and gets me back to South Florida.

Jeff

HD4Mark · 09-12-2013, 07:06 AM

Jeff,
If it is any consolation our oil pressure gauge went out only one time. When leaving on a short trip I notice zero pressure

Hmm I figure there is also an red idiot light but it is not on. So off we go and the temp never gets anywhere near too high so obviously there is oil pressure. When we stop to check in the CG and start back up it is back it was working. Hasn't done it again since and that was a year ago.

One good thing about it is that it makes me even more aware of the gauges.

BTW we are also on a Freightliner chassis with a Cummins ISC.

DJJ · 09-12-2013, 07:36 AM

Tony Lee- your thought would be the easiest to fix (so of course that can't be it) I have already used up my allotment of luck for this life time. I have a battery boost switch that connects the house batteries to the starting batteries if needed for start up. So, if the gauges don't work again I think I will shut everything down and restart using the switch to see if the problem goes away.

Other wise I guess I start tracing things out looking for bad grounds and connections.

Thanks Mark, I hope I never see a no oil pressure reading again, talk about pucker. Later I thought that the computer would have shut the motor down if I lost all oil pressure.

Thanks for the response, Jeff

FIRE UP · 09-12-2013, 10:14 AM

Quote:

Originally Posted by DJJ

Tony Lee- your thought would be the easiest to fix (so of course that can't be it) I have already used up my allotment of luck for this life time. I have a battery boost switch that connects the house batteries to the starting batteries if needed for start up. So, if the gauges don't work again I think I will shut everything down and restart using the switch to see if the problem goes away.

Other wise I guess I start tracing things out looking for bad grounds and connections.

Thanks Mark, I hope I never see a no oil pressure reading again, talk about pucker. Later I thought that the computer would have shut the motor down if I lost all oil pressure.

Thanks for the response, Jeff

Jeff,
Yes, your engine will shut down it there is a "true" loss of oil pressure. In fact, that's why many CAT engines crank a bit more than their Cummins counter parts due to the sensors have to detect at least some oil pressure for the system to activate and start the engine.

Now, if your VDC or our MMDC shuts down completely, that is, ALL YOUR GAUGES simply shut down, for the most part, that will not shut down the engine and trans operations. Because, as stated earlier, those computers simply received data from the various sources and send it to the dash.

You talk about a scare, I don't know if you read my post(s) about my issues back quite a few months ago but, it was alarming, to say the least. A long story short.

Cruising along I-10 east bound, very close to Lordsburg NM and the road is smooth as glass, temps are perfect, weather could not be better, traffic is almost nil, cruise is set at 60, and I'm thinking to myself as we're headed east towards Texas, man, this is perfect. Well, about 10 seconds after I had that thought, my cruise shut down on its own. Hmmmmmm. I looked down and YEEEEEEOOOOOOOOOWWWWW, NO GAUGES AT ALL!

Talk about panic. My first reaction was to hit the throttle pedal to confirm engine shut down. Well, to my amazement, I picked up speed immediately. The trans had upshifted and I was accelerating down the freeway. Hmmmmmm, Still NO GAUGES. I mean, the speedo, the tach, the oil pressure, temperature, voltmeter, and turbo-boost all, dead. Plus, no cruise control. I gave the rig a quick test, I let off the throttle which, would normally employ the exhaust brake, NOPE, NO EXHAUST BREAKE!

Ok, this is getting ugly REAL FAST. So, approaching an off ramp for Lordsburg, I took it and we headed to a place to park so I could begin contemplating suicide because of the instant thoughts of what it would cost us to have this nightmare fixed.

Well, a very, very long story short, it was ONE WIRE, in that "J1939 Data Link" that was intermittently broken. I placed a call to Freightliner customer Assistance and within about 30 seconds of describing our situation, that's exactly what the tech on the line described, "YOU HAVE A LOSS OF COMMUNICATION OF THE J1939". I said " Loss of what???" At that point, I'd never heard of the J1939 and any of its operation.

Ok, enough of the story. After a terrible experience at the worst Freightliner service centers on the planet, "On the Border Freightliner" in El Paso TX, we headed home without anything fixed. But, we're fortunate enough to have what's called the "Trip-Tek" information system that's overlaid on the back up monitors screen. With a push of a button, I get the most important engine vitals on that screen.

So, we drove all the way home from El Paso TX, over 700 miles without any gauges or, cruise control (what a serious pain in the a$$ and foot and leg) and no exhaust brake.

So, that's our story. So, a gauge popping in and out of service to me, would ne nothing. I'd fix it but, compared to what we went through, it would not have the "wow" factor. Anyway, hope you get it fixed, anything like that can wear on the brain, trying to figure out just where the issue is.
Scott

DJJ · 09-12-2013, 06:18 PM

Fire Up, thanks for the info. We bought the MH in May, our first, and hit the road a month later and have not been home since. So I have had to learn a lot in a short time.

FIRE UP · 09-12-2013, 06:47 PM

Quote:

Originally Posted by DJJ

Fire Up, thanks for the info. We bought the MH in May, our first, and hit the road a month later and have not been home since. So I have had to learn a lot in a short time.

DJJ,
Right on Partner, get out and use that thing. If you have issues, then ask. Someone here may be able to help. If you don't, great. Nothing like a good time in traveling. I can't wait to get out again.
Scott

Fred Cooper · 09-15-2013, 09:48 PM

DJJ

Look at this link for a Freightliner service bulletin explaining how your system works and some troubleshooting info.

http://ww2.justanswer.com/uploads/go...44_sbu5412.pdf

I've had two instances where my speedometer simply coasted down to zero while the coach still ran down the road at 64 mph, and the VMSpc was reporting everything normal including road speed of 64. It seems to have cured itself so I have not done further troubleshooting.

Good luck

Fred