2009 CAMELOT - Low Coolant Check Engine Light on - ENGINE DERATED 30% - HELP1

[Rick Hall]

Hello, I have a 2009 Camelot with a Cummins ISL 425. My low coolant on the display and Check Engine Light is on but, overflow tank is showing at the full max level with engine hot or cold. I'm on the road in AZ currently and looking to see if I can bypass this to get back home and troubleshoot / repair? The sensor is a three wire! Because the check engine light is on the engine has derated to 70%. That extra 30% would be nice on pulling these grades here. Any thoughts? Ideas would be appreciated.

Thanks,

Rick

[1nolaguy]

If your engine is reading hot and the coolant tank remains at max full whether the engine is hot or cold there is a good possibility the problem might be water pump related.before you head out I would suggest having that check out. Coolant system errors that are not addressed can lead to extremely costly repairs.

[DavidL]

Check the tank, not just the overflow.  It's possible the tank is low and the overflow is full.

Wherever the sensor is, that's the tank that is complaining.

If it's a sensor, then, you could bypass the switch, but do that carefully as you wouldnt' then have that as a safety device.

You ideally also would have a scan tool to double check why the engine is complaining.

 

A water pump issue will certainly affect the temp (no indication from the OP that the temp was irregular -yet...)  But it shouldn't affect a low coolant indication unless the pump leaked the coolant out...

Edited August 15, 2023 by DavidL

[Rick Hall]

The overflow tank is full and that's where the sensor is located. I have blue fire and the code says 111-18 Coolant is low. However, tank is full. Engine is not overheating and is running all normal temps. I'm assuming the sensor is bad that's why I wanted to know how to bypass or jump it. Not sure which wires to jump since it has three Prongs / wires in the connector.

Also, there are no leaks and not running hot. All temps in range and are fine. 

Edited August 15, 2023 by Rick Hall

[Ivan K]

The level should fluctuate quite significantly between cold and hot, eventhough I know that it takes for ever to cool down in AZ. But, if you are only concerned with the sensor...

Here is a McGiver way at own risk but it wouldn't be the first time it was done.

3 wire means there is a reference voltage on one of the wires, one ground and one return signal to ECM. I would disconnect and confirm the voltage and ground wire first. A dirty way of faking the signal is disconnecting the connector and shorting the reference (~5V) wire to the return wire. These could have the same color. NOT to the ground, which might be a white wire!

[Rick Hall]

32 minutes ago, Ivan K said:

Thanks Ivan, that worked! The hardest part was trying to find one of Macgyver's paper clips. 

 

[Tom Cherry]

1 hour ago, Rick Hall said:

The overflow tank is full and that's where the sensor is located. I have blue fire and the code says 111-18 Coolant is low. However, tank is full. Engine is not overheating and is running all normal temps. I'm assuming the sensor is bad that's why I wanted to know how to bypass or jump it. Not sure which wires to jump since it has three Prongs / wires in the connector.

Also, there are no leaks and not running hot. All temps in range and are fine. 

I admit...I am STUMPED on this one...  and here is why....  OK....

@Rick Hall

I have a LOT of info and prints on the Medallion ILB system in your MH...more than the average....Look BELOW.  The System Connectors and the Manual are some that Medallion sent me.  I had a FALSE alarm...in that the Bay Door wire (yes, we have NO SWITCHES...but Monaco ran the wire in the harness and it got NICKED and that was the LIGHT and BEEEEEPPPP.  So, they told me WHICH wire to cut behind the Medallion if I didn't find it).  The Light you are getting is coming from the ECM...and that is what is NOT on any print.  

OK...that means that you do NOT want to go wildly messing with bypassing or such.  There are MANY hits on the Cummins Low Coolant Sensor.  This one is for a DIFFERENT engine...

OK...I called OUR Tech Support ( @Frank McElroy ).  He is the MOST knowledgeable person on here and knows more than 75% of the techs.

Here is what we NOODLED out after looking at the ECM data for my ISL (same as yours).

First, YES, there is a DERATE code that should be in the ECM.  The Sensor, as I supsected, is NOT feeding the Medallion direct.  It comes from the TOTAL ECM output or data buss (J-1939).  I feel confident as I figured that out first...but having Frank confirm makes me feel better..  LOL>

OK...here are your options.  There is NO shorting or paper clip or anything.  DO NOT ATTEMPT....

Next, the ECM is looking for a Reisistence...and if it don't see it....it AIN'T HAPPY.  All the "short with a paper clip is HOGWASH"
 

NEXT...and Frank does NOT have a Blue Fire since he has the complete Cummins Insight and can read all the ECM codes.  You BlueFire does NOT have that capability.  

IF you Blue Fire has a screen or scroll capability and is "CAPABLE" of really reading the Cummins Codes (as the Insight does), then TRY Scrolling.  NO JOY....it ain't gonna work.

NOW, here is what Frank THINKS, and he is out and about and will try to chime in later on, that ONCE your engine has been DERATED, it takes a Cummin's INSIGHT Laptop or Device...like the techs have....to Clear the CODE.  BUT, they will first go through all the codes and verify that there is NOT some hidden code that also derated it...perhaps coincidentally....  BUT, once the Cummins ECM takes charge...it PROBABLY will NOT go away until Insight says CLEAR.

Your options are limited....but here are some.  SO...please be aware that these will NOT damage your engine and if you do something crazy, you can.

FIRST....ARE YOU 100% sure, Engine COOL, that the overflow is full.  MINE is a bugger to see and it take a high powered LED Maglight to see the level.  CHECK THAT, MANUALLY....or if you have...proceed.

NEXT.  UNPLUG the sensor.  Make sure that all the contacts are clean.  I actually use a product that Lowes (or many electrical supply houses have).  NoAlox.  Gardner Bender makes Ox Gard Anti-Oxidant and Lowes sells it.  Think of toothpaste with some ground up, very fine Aluminum and Copper DUST.  Use it on a Toothpick, sparingly, and coat the male and female contacts of the harness.  That will improve and get rid of any oxidation... OXIDATION will impact resistance....THUS....drive the system crazy.  Plug and UNPlug the connector a few times.  You want to make sure that the contacts are clean.  A straight sewing needle on a cork will allow you to sort of pick and scratch.

NOW...restart and let it run....maybe a few minutes.  IF the resistance comes back and is within range, it SHOULD clear the code.

OK...the FINAL YouTube "GUARANTEED to FIX IT".  UNPLUG the sensor.  Frank thinks that the YouTuber is wrong.  BUT, there ARE some Cummns engines that will just say.  Hey, You got a sensor issue and we can't fine it".  Lights stay on, but you can DRIVE....with Full power.  Frank thinks, but is NOT sure...that once derated...until the issue is fixed (new sensor) or the code is cleared....that it is gonna stay low.

IF your Blue Fire has a CLEAR CODES function...TRY THAT.  Past that, DRIVE IT and get a NEW sensor.  There are aftermarket ones...but the sensor was put in by MONACO...and is NOT something that Cummins supplies, but Cummins SHOULD have a replacement part....or maybe a OTR Truck Supply distributor.

That's it...  and I went over this, precisely with Frank...for my OWN learning and also to keep you from doing something you might regret...

I also printed out the ECM Derate parameters for our engines....YES...that is a critical one and ENABLED...so when I read that to Frank, it cleared it up

Good LUCK...

Medallion 10 button.pdf M3 ILB system connectors_pinouts.pdf Monaco 10 button ILB Operators Guide _Rev2-1.3.08_.pdf Low Coolant Derate ECM Parameters Cummins ISL Print Out.pdf

17 minutes ago, Rick Hall said:

 

Ivan's a BETTER McGyver than I AM.  BUT.  IF you cleared it MOMENTARILY and it comes back, per how the ECM is monitoring it....this may be short lived.  I SURE HOPE SO...and you need to read my post.

Ivan, @Ivan K  @Frank McElroy

Thanks....  Hope it is permanent...  Please read my post about what Frank said....  LETS hope we can add this to our OWN YouTube Channel...

MIGHT BE just a bad connection and it got cleaned up.  

Rick, Let  us know...

Thanks.

[Ivan K]

It is, of course, a temporary solution to get Rick home and replace the sensor. The safety aspect has been removed with known risk. It would be better to use a small resistor but since Radio Shack is gone, not easy to find one. Since it is a level sensor, the ECM is not looking for variable signal, it does not care as long as the tip is wet. 

[Rick Hall]

Thanks Tom, Thats some good advice and information. I have some homework to do I see. I'm going to go get into this and report back. Again, thank you! 

[Frank McElroy]

Although you in effect disabled the low coolant sensing system, there are risks involved. 

Cummins does an engine derate when detecting low coolant in the system because at full power, if you do lose coolant,  by the time a high coolant temp light comes on you will likely already have done serious damage to the engine.

On my coach, I would not take the risk on a long trip home and no way would I climb hills at full power.