Community Forums

Applejack · 08-05-2008, 05:17 AM

Is there someplace that the meaning of the freightliner warning messages is documented ?
Quite often I get a " Low Sytem Voltage" message on startup and it changes to a "Auto Idle Threshold" message. When this happens I also see the volt gauge fluctuating. If I shut the engine off and restart everthing is normal.
My battery voltage is at 12.8 or 12.9 so I dont think that low battery voltage is the cause. It is a 2008 400 ISL.

Applejack · 08-05-2008, 05:17 AM

Is there someplace that the meaning of the freightliner warning messages is documented ?
Quite often I get a " Low Sytem Voltage" message on startup and it changes to a "Auto Idle Threshold" message. When this happens I also see the volt gauge fluctuating. If I shut the engine off and restart everthing is normal.
My battery voltage is at 12.8 or 12.9 so I dont think that low battery voltage is the cause. It is a 2008 400 ISL.

ms911 · 08-06-2008, 03:21 AM

I have that message on occasion usually when my battery is a little low. It will kick the rpm up to a high idle to charge the battery. I have a 400 ISL (2005). I do not think I would worry about it. Don't shut it off and see what happens.

SteveG · 08-06-2008, 04:35 PM

You did not mention what instrument provides this message. On my 2004 Journey (Freightliner) they provided a Drivers Information Center manufactured by Medallion. It sounds like we have the same instrument. If so,

The alarm screens indicate:
1st The item in alarm state
2nd Current value
3rd The threshold that needs to be met to eliminate the alarm.

AUTO IDLE
10.0 volts
Threshold
13.4v

The following is taken from a file titled "RV Friendly Interactive Customer Info Center.ppt. I can not recall where I found this file or who sent it to me. If you would like ac opy let me know by private message how to contact you via e-mail and I can forward you a copy.

"The Auto Idle Feature will automatically increase the engine RPM when a low system voltage is sensed under the following conditions: (Gear = Neutral ,Park Brake is set, the engine is at idle > 500 rpm, the system voltage drops below 12.2V, and the service brake is not on). The MMDC will increase the idle speed using the cruise control feature until the battery voltage at the engine ECM (broadcast over J1939) reaches 13.4V. This is done by broadcasting cruise on and cruise accelerate switch status messages until a 40-rpm increase occurs, with an increase in RPM every 5 seconds with a max increase to 1800 rpm. At 13.4V the engine rpm will be held constant until the service brake is depressed or the transmission is shifted out of neutral. At that time the auto idle feature will be disabled and the engine will return to normal operation. The auto idle feature will not be re-enabled unless the engine rpm < 500 or the gear is shifted out of neutral."

The Drivers Information Center is connected to a module called a MMDC. The following is from the Medallion website Here

"Multiple Module Data Concentrator (MMDC)
The Multiple Module Data Concentrator (MMDC) is Medallion's instrument system controller for vehicles equipped with electronically controlled engines supporting the SAE J1939 Data Link Standard. At the heart of the Instrument Systems is the MMDC, but it is more than just a controller:

"¢ The MMDC gathers information from the SAE J1939 data link, various sensors scattered throughout the vehicle, and its own internal Pressure Sensors and conditions this information for display.

"¢ The MMDC acts as a Gateway between the mission critical SAE J1939 data link and other data links installed in the vehicle.

"¢The MMDC supports a distributed multiplexed communication and control architecture.

The MMDC was designed to perform in harsh environments and complex applications. We used surface mount construction and encased the MMDC in a rugged potted enclosure to meet SAE J1455 environmental standards."

Hope this helps. SteveG

DiamondDan · 09-06-2008, 11:39 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SteveG:
You did not mention what instrument provides this message. On my 2004 Journey (Freightliner) they provided a Drivers Information Center manufactured by Medallion. It sounds like we have the same instrument. If so,

The alarm screens indicate:
1st The item in alarm state
2nd Current value
3rd The threshold that needs to be met to eliminate the alarm.

AUTO IDLE
10.0 volts
Threshold
13.4v

The following is taken from a file titled "RV Friendly Interactive Customer Info Center.ppt. I can not recall where I found this file or who sent it to me. If you would like ac opy let me know by private message how to contact you via e-mail and I can forward you a copy.

"The Auto Idle Feature will automatically increase the engine RPM when a low system voltage is sensed under the following conditions: (Gear = Neutral ,Park Brake is set, the engine is at idle > 500 rpm, the system voltage drops below 12.2V, and the service brake is not on). The MMDC will increase the idle speed using the cruise control feature until the battery voltage at the engine ECM (broadcast over J1939) reaches 13.4V. This is done by broadcasting cruise on and cruise accelerate switch status messages until a 40-rpm increase occurs, with an increase in RPM every 5 seconds with a max increase to 1800 rpm. At 13.4V the engine rpm will be held constant until the service brake is depressed or the transmission is shifted out of neutral. At that time the auto idle feature will be disabled and the engine will return to normal operation. The auto idle feature will not be re-enabled unless the engine rpm < 500 or the gear is shifted out of neutral."

The Drivers Information Center is connected to a module called a MMDC. The following is from the Medallion website Here

"Multiple Module Data Concentrator (MMDC)
The Multiple Module Data Concentrator (MMDC) is Medallion's instrument system controller for vehicles equipped with electronically controlled engines supporting the SAE J1939 Data Link Standard. At the heart of the Instrument Systems is the MMDC, but it is more than just a controller:

"¢ The MMDC gathers information from the SAE J1939 data link, various sensors scattered throughout the vehicle, and its own internal Pressure Sensors and conditions this information for display.

"¢ The MMDC acts as a Gateway between the mission critical SAE J1939 data link and other data links installed in the vehicle.

"¢The MMDC supports a distributed multiplexed communication and control architecture.

The MMDC was designed to perform in harsh environments and complex applications. We used surface mount construction and encased the MMDC in a rugged potted enclosure to meet SAE J1455 environmental standards."

Hope this helps. SteveG </div></BLOCKQUOTE>

So on my new Damon Astoria, if the unit has been sitting unplugged for more than a few hours, when I start, I get the low voltage warning, high idle, etc. The dash volt meter fluctuates between 13ish and 9ish. The information center shows the ABS LED voltage of 8.4 and the system output at 15.

Does this sound like a bad chassis battery? The rig starts fine - and the ABS LED voltage comes up to 13.1 after less than a minute. I can't find any definition of what the ABS LED (LED ABS?) voltage is. Any help much appreciated.
dan

FleetMan · 09-06-2008, 01:46 PM

We discussed this message at the Camp Freightliner session I recently attended. Per the instructor, this often indicates a chassis battery with a bad cell. A load test of the chassis batteries may be in order.

**Gary RVRoamer** · 09-06-2008, 05:44 PM

Normal system voltage should be well above 12.8 or 12.9 - more like 13.7-14.4 range. It sounds like a bad chassis battery (or two) to me.

DiamondDan · 09-06-2008, 06:15 PM

Thanks very much for the informed replies. I'll have them tested this week. I'm still in the dark as to what "ABS LED" voltage is. The documentation on the Information Center is not that deep.
-dan

GDub · 09-23-2008, 06:22 PM

A suggestion for low battery, the diesel pushers have so much electronic loads on them now, the engine batter hardly stands a chance when the rig is shut off for a few weeks. I recommend you install a TRIK-L-start charger. This new feature called a Trik-L-Start will help maintain the chassis battery anytime the unit is plugged into 110V shore power and the battery disconnect is in the "on" position. The Trik-L-Start device monitors battery voltage in the house batteries and compares it to the chassis battery. When the Trik-L-Start senses the chassis battery voltage is approximately ½ volt lower than the house battery, it allows up to 5 amps current flow to the chassis battery. The circuitry within the Trik-L-Start prevents back feeding of electricity from the chassis to coach battery so if 110V power is interrupted, the chassis battery will not be discharged. Additional information can be found at http://www.lslproducts.com/TLSPage.html.

Winnebago now installs these on the diesel pushers, I bought one and installed it easily and have not had a problem since.

good luck.