Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 09, 2025 ...

Bad Coolant Level Sensor?

July 06, 2015, 10:39:28 am

While on our short weekend trip to the mountains everything was fine till I hit a rough place in the road. Check engine light came on and then derated. We pulled over, turned off engine and restarted. Check engine light went out and continued on, Code PSN 111 FMI 2

 On our way back we hit same rough area and light came on again. Same routine but light would come back on after a few miles.  Checked scanguage and it gave PSN 111 FMI 2, same as before. Limited internet but best I could figure was coolant level.  Reservoir was topped off the day before. This continued on for about 50 miles till we got into a town and off the two lane road. 

While there I unplugged the coolant sensor from the black metal surge tank and the plugged it back in. Took off and all was good again. We hit a set of railroad tracks about a block away and it jostled the whole coach. Drove the whole way in, 200 miles, with no problem.

Do you think it's a bad sensor or maybe just a loose connection? I tried to find the ECM to check the connects there but it still remains unfound.  Anyone know where the ECM is located on a 40' 2000 U320?  Also, is there a float or sensor in the plastic reservoir or just in the metal surge tank?

  I had received another code PSN 620 FMI 4 ( Sensor Supply Voltage low #2 circuit - shorted low) on a previous trip but have since replaced all the batteries and didn't get it on this trip.  Wondering if now related.

Any help or advise would be appreciated. Thanks in advance guys!

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Re: Bad Coolant Level Sensor?

Reply #1 – July 06, 2015, 05:09:50 pm

Bruce,
I have a friend who carries a spare coolant sensor.  He wasn't as lucky as you.  When his failed, power dropped way down, so he now carries a spare.
If it is not acting up it will probably be hard to know for sure if it was the connection or the sensor.  If it were mine I would probably change the sensor, while I am not one just to change parts, I would want to take that part out of the equation.
Jerry

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Re: Bad Coolant Level Sensor?

Reply #2 – July 06, 2015, 06:45:35 pm

I've had to replace mine twice.

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Re: Bad Coolant Level Sensor?

Reply #3 – July 06, 2015, 07:15:31 pm

The coolant level Sensor looks identical to the model we use on generators, usually wired to the high temp alarm, when coolant level goes low, it sends over temp alarm.  On the computer models, it triggers computer sending alarm.  When defective, we  disconnect the wire connector until we install a new Sensor. Not sure if that is method used by Foretravel , will try one day.
Level Sensor @ Cummins A029Y148 $125.00 list

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Re: Bad Coolant Level Sensor?

Reply #4 – July 06, 2015, 11:47:15 pm

Thanks, I will change out the sensor and keep my fingers crossed for our big trip in a few weeks.

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Re: Bad Coolant Level Sensor?

Reply #5 – July 07, 2015, 11:26:29 am

Bruce, can you take a couple of photos to post of the sensor and location when you do this?
Thanks, Dick

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Re: Bad Coolant Level Sensor?

Reply #6 – July 07, 2015, 03:13:00 pm

Dick,  Can do.  I ordered the sensor this AM and will get it in a few days.

Went back out and looked....still haven't found that ECM yet.....probably looked at it three times.....hysterical blindness?

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Re: Bad Coolant Level Sensor?

Reply #7 – July 09, 2015, 08:51:04 pm

I think the Cummins ECU on ours is on the front passenger side of the motor. If I lift the bed and lean in and to the left, it is close enough to the top to see..
Dick

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Re: Bad Coolant Level Sensor?

Reply #8 – July 09, 2015, 09:28:29 pm

Right,  Mounted on the engine on curb side toward front of coach.

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Re: Bad Coolant Level Sensor?

Reply #9 – July 09, 2015, 09:34:39 pm

On my 2001 and others of similar year model, the low water level sensor is located on the black tank to right of engine, seen when the rear tail gate is open, the black tank has a radiator cap on top, there is an electric connector attached with a quick disconnect.  The ECM is on curb side of engine, hard to see but open bed and have fun, not easy on the ISM.

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Re: Bad Coolant Level Sensor?

Reply #10 – July 09, 2015, 11:33:31 pm

Thanks guys, I did a search and thought that it was supposed to be there but couldn't see it from underneath or from top. Guess I'll lean in further. Was going to check connections but if it's that hard to see it's probably harder to reach. Probably best left alone.

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Re: Bad Coolant Level Sensor?

Reply #11 – July 10, 2015, 12:26:33 am

ECM on 2000 Cummins is right behind the fuel filter on side of engine. Do not mess with this critter as the pin connections are a devil to fix without removing said filter. I found this out last Jan in Phoenix area. Not a cheap part to play with.. The ECM is a small box thing fastened to engine block with a big bundle of wires going to it.
As Dave said the sensor is at bottom of the Black resevoir tank to right of engine behind door. It has a ceramic probe that does the sensing. You can take it out and qhickly put your finger (or someone elses over hole while you clean it up and replace). Simple out and in.
JohnH

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Re: Bad Coolant Level Sensor?

Reply #12 – July 16, 2015, 03:29:08 pm

I changed to the sensor today. Thought I would post the part # in case someone else needed it.

Coolant level sensor (4 wire config.):
Cooper Standard Mini -Tech
Part# 086714A0001

Dick, you wanted pics but for some reason every time I hit the "insert image" icon it closes the whole site and I'm back to the desktop. (iPad with IOS 8.1) I'll work on it, sorry.

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