Author Topic: Dash Temp Gauge Not working - CEL on intermittently  (Read 222 times)

Paul Haaf

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Dash Temp Gauge Not working - CEL on intermittently
« on: September 28, 2021, 09:28:35 PM »
On a short trip last weekend our red Check Engine Light turned on followed by a blue Engine Warning light. I noticed the Dash Temp reading was not even in the scale, it was pointing directly left.

The cycle repeated about 5 times in a 20 minute span. The engine also reduced power and slowed to about 45 mph. This cleared up as soon as the lights went out.

Aladdin showed Engine temp at 204 and transmission at 212 during this episode.

I checked coolant and the reservoir was fine but there was a little fluid on the bottom tube of the reservoir and on the lower coolant hose. I tightened the hose clamps and looked for anything else disconnected. Wires near the cooling sensor are exposed as the black wire loom has deteriorated and one wire appears cut, probably from previous service, i didn't find another loose wire it could have connected to. I plan to replace the wire loom and double check the conductors for damage.

I looked in wire schematics but none show how the dash gauge connects to sensors or the ECM. The light works on it and there are three other wires connections all sound.

About a month ago I rebuilt the seals on the Hydro pump solenoid, my first trip it ran hot and cut back at 225 degrees, I adjusted the solenoid and the next road test was fine and have put over 1000 miles on since with no issues.

If you made it thru all of this, nice job!

Any advice will be appreciated.


 
« Last Edit: October 20, 2021, 02:46:19 PM by Paul Haaf »
2006 Monterey-Ventura-IV 36'
CAT C9 400HP - Allison 3000

Looking to add a tow vehicle
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Paul Haaf

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Re: Dash Temp Gauge Not working - CEL on intermittently
« Reply #1 on: October 20, 2021, 02:59:17 PM »
Update on this issue:
I brought it to a local Freightliner service center and they diagnosed a faulty Engine Oil Pressure sensor, that was putting on the CEL and affecting the engine running properly.

I have it in the service center again now to have the oil pressure switch replaced and so far all analog gauges are working properly. The Aladdin gauge always drops to 0 PSI when the CEL turns on but the analog gauge is always around 1/3. It usually lasts a minute or two and then clears. The engine degrades and then restores. It has been a nuisance but has not stranded us.

I will update again after the repair is done.
 
2006 Monterey-Ventura-IV 36'
CAT C9 400HP - Allison 3000

Looking to add a tow vehicle

Steve Huber Co-Admin

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Re: Dash Temp Gauge Not working - CEL on intermittently
« Reply #2 on: October 20, 2021, 03:28:10 PM »
Paul,
A faulty/intermittent oil pressure sensor could cause your symptoms. The readings on the Aladdin are normally the ones the ECU sees while the dash gauges are pretty much "for entertainment only". Your reported engine and tranny temps are normal for the C9.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp