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Cummins ISB Engine Code Water In Fuel

I found out some interesting information about this code involving the fuel / water separator. The wiring for both the coolant sensor and fuel / water sensor namely the ground is shared. When the code for the water in fuel sensor popped up it also triggered an engine coolant temperature code to flash as well. It was obvious that the coolant system was operating normally leading to the first assumption that there was an electrical fault.

Since doing this video and clearing the codes there has been no repeat fault problem. Changing the primary fuel / water separator sensor was the answer and no codes have come back to haunt us. Note: If you’re wondering what those two black spots on the monitor are…the screen is starting to deteriorate. Replacement is in the works for this one.

The sensor in the fuel – water separator is located in the serviceable plastic bowl. I realized after it was not very clear in the video. The lighting was not sufficient…my apologies. Also the bus is a 2009 and not a 2007 as I mentioned in the video. The 2007 would have been equipped with a Merecedes MBE 900 diesel engine. The ISB models have been very good to us even considering a few failures with turbos, water pumps and exhaust leaks.

It’s actually easier to deal with a mechancial problem than it is with an emission problem that we have been experiencing with the Mercedes diesel engines. All of the ISB mechanical failures mentioned above were covered by warranty. Nice!