9900 gauges not functioning correctly

[Redland1]

I was driving last night to an oil well to deliver Frac sand and the traffic light in front of me turned red so I started to downshift.When I came to a stop I saw that the RPm gauge was pegged at 1900 RPM but I could hear that the engine was at idle and also noticed that the coolant temperature was completely at 0 degrees and a low oil pressure light came on.I shut the engine off to reset the gauges and sure enough everything went back to normal.What could have caused this?

[Rawze]

electrical noise?

make sure your voltage is not spiking or dropping out?

[Squish099]

Sounds like cab controller freaked out.. Maybe lost communication with ecm for a sec.

[DVT873]

AFIK no cab controller on a 9900 unless it is real new. Even then I still think no cab controller but would need to look. HX might have one. VIN would tell. Hopefully maybe just a datalink hiccup. Almost all instrument info comes via datalink from the engine ECM. Fuel gauge and volt gauge are probably direct i.e. non data link. Air pressure gauges may still have actual air line going to them. Instrument cluster will be fused. Did you notice if the fuel and volt gauges stayed normal?

9900's are pretty tough trucks. Paystars (real tough trucks) share much of the same DNA but have heavier duty frames. Cabs, wiring, plumbing very much the same. These trucks, especially the Paystars would not be a good choice for general freight! Should be good or what it sounds like your doing.

[marek4792]

Check your firewall pass through connection could be losing connection intermittently perhaps?

[Redland1]

(05-15-2021 )DVT873 Wrote:  AFIK no cab controller on a 9900 unless it is real new. Even then I still think no cab controller but would need to look. HX might have one. VIN would tell. Hopefully maybe just a datalink hiccup. Almost all instrument info comes via datalink from the engine ECM. Fuel gauge and volt gauge are probably direct i.e. non data link. Air pressure gauges may still have actual air line going to them. Instrument cluster will be fused. Did you notice if the fuel and volt gauges stayed normal?

9900's are pretty tough trucks. Paystars (real tough trucks) share much of the same DNA but have heavier duty frames. Cabs, wiring, plumbing very much the same. These trucks, especially the Paystars would not be a good choice for general freight! Should be good or what it sounds like your doing.

It’s an 03’.Air pressure gauges do have an airline.Honestly I don’t remember What the readings were on those two.I can say for certain that the oil temperature gauge hasn’t worked since I purchased the truck a month ago and also the axle temp gauges are not functioning.I purchased an oil temp gauge from eBay to replace the old one and it still didn’t work.

[Redland1]

(05-15-2021 )Rawze Wrote:  electrical noise?

make sure your voltage is not spiking or dropping out?

Voltage is steady.

[Chamberpains]

Did the speedo peg off or point straight down during this event?

This would show that the dash lost data connection. If it stayed where it should and those isolated gauges went cross-eyed then it was more then likely isolated to the communication of the those systems.

[DVT873]

(05-15-2021 )Redland1 Wrote:  

(05-15-2021 )DVT873 Wrote:  AFIK no cab controller on a 9900 unless it is real new. Even then I still think no cab controller but would need to look. HX might have one. VIN would tell. Hopefully maybe just a datalink hiccup. Almost all instrument info comes via datalink from the engine ECM. Fuel gauge and volt gauge are probably direct i.e. non data link. Air pressure gauges may still have actual air line going to them. Instrument cluster will be fused. Did you notice if the fuel and volt gauges stayed normal?

9900's are pretty tough trucks. Paystars (real tough trucks) share much of the same DNA but have heavier duty frames. Cabs, wiring, plumbing very much the same. These trucks, especially the Paystars would not be a good choice for general freight! Should be good or what it sounds like your doing.

It’s an 03’.Air pressure gauges do have an airline.Honestly I don’t remember What the readings were on those two.I can say for certain that the oil temperature gauge hasn’t worked since I purchased the truck a month ago and also the axle temp gauges are not functioning.I purchased an oil temp gauge from eBay to replace the old one and it still didn’t work.

03 definitely DOES NOT have a body computer. The speedo and tach housing is "smart" sounds like a loose connection. There should be two fuses in the block behind the dash panel on pass side. F4-A and F5-C . Speedo. Tach, Oil pressure gauge and light, Water Temp gauge and light get there info from the engine ECM. Oil pressure and Water temp gauges are the same functionally.
Oil temp will have a sender on the block somewhere. It is hardwired. temp signal does not come from the ECM. Probably a bad sender or broken wire or bad connection. The F4-A fuse is the common power for all those temp gauges. Not sure on the fuel sender. The wiring diagram is a little vague. There should be a gauge manual but I can't find it at the moment.