Help- Air Gauge Issue 2004 Ult. Advantage / Spartan

[Subguns]

My coach just turned a year old and am still having an intermittent issue with the Primary (#1) air gauge. Under normal operation the gauge falls to 0, sounds alarm, then immediately returns to normal. There is NO loss of air pressure just the alarm. Working with Spartan the dealer has done the following:
- Replaced both Air Pressure sending units. (#1 twice)
- Replaced the Speedo head which controls all gauge functions
We know this has been an issue in other Ultimate Freedon / Advantage coaches with Spartan and Cummins 400 HP ISLs.
Has anyone else experienced this and found a solution? Overall this coach has had very few issues in the first year, with only this one not resolved as of yet.
Any help with similar problem would be appreciated.

[Subguns]

My coach just turned a year old and am still having an intermittent issue with the Primary (#1) air gauge. Under normal operation the gauge falls to 0, sounds alarm, then immediately returns to normal. There is NO loss of air pressure just the alarm. Working with Spartan the dealer has done the following:
- Replaced both Air Pressure sending units. (#1 twice)
- Replaced the Speedo head which controls all gauge functions
We know this has been an issue in other Ultimate Freedon / Advantage coaches with Spartan and Cummins 400 HP ISLs.
Has anyone else experienced this and found a solution? Overall this coach has had very few issues in the first year, with only this one not resolved as of yet.
Any help with similar problem would be appreciated.

[BucknJeff]

So here's a good guess.

On a freightliner, there is a chassis control module that multiplexes all of the sensor signals from the engine and chassis, and sends the information into the main chassis data bus. In the front of the coach, the instruments are connected to another device that decodes the chassis data (generally this is the instrument cluster) and operates the gauges.

We had exactly the same issue, but in a freightliner. It turned out to be this Chassis Control Module input device, located in the back, near the main engine computer.

Hope this helps.

[Demoman]

I am having a problem with my 02 Journey on a Frieghtliner Chassis. When you hit a hard bump in the road all of the indicator lights will come on for a few seconds then go off. It is intermitent. Sometimes the gauges will lock up sometimes they won't. Freightliner just changed the computer that controls the gauges last week. It did not fix the problem, back to the dealer tomorrow.

Steve

[Ptribbey]

I know this is an old post, but I am new to the forum and was reading the older posts. If anyone is interested, Spartan has a recall related to the wiring harnesses jumper cable to the air gages. Service bulletin # RSB-400-001.

The recall states the gages are not properly calibrated, and the warning indicator can activate when the actual pressure is below 60 psi.

Don't know if this could be related to your problem. The recall states to covers chassis from 01/2002 to 3/31/05.