Read a lot of comments about this, but have not seen any solutions. My 06 has had the grid heater light come on with chimes 4 times in the last year. Every time I was towing, going down a mountain pass, about 70 mph, foot off the pedal. Most have said it is due to excessive return flow, but if that was the problem, seems like the light would come on going up the pass, foot on the pedal and higher pump pressure?


I have a couple questions, anyone had this grid heater light issue and fixed it? What was the fix? How does the Cummins engine system measure injector return flow?


My 06 has 100k miles, runs perfect, starts easy and has no fuel in oil. When the grid light came on, I didn't get any engine codes on my reader, but resetting the codes clears the grid light. Thanks

 

the light is an indication of several different problems with fuel, the cp3 is a piston pump that changes stroke to maintain the pressure the ecm calls for on the back of the cp3 there is the fca that has two wires on it, if you unplug it the rail pressure will peg my 30,000 psi gauge, the ecm sends a width modulated 5 volt signal to the fca to set the pressure the pore of the 5 volts the lower the pressure, most over pressure problems is a sticky fca i learned i could clean it with break cleaner and cure most problems, take it out and shake it back and forth, it should rattle easily, computer calculations of the pulse width compared to the throttle position and rpm can determine rail flow and will compare this to what it should be if it is different it set's the code off, when the pressure gets up above about 28,000 psi a prv opens up to bleed it off causing a difference, some of these problems especially the intermittent problems can be hard to find. i have a truck that ATS in Colorado installed a second cp3 on, about every month or two it would throw a code and before i could do anything it would be OK i finally mounted a rail pressure gauge to the steering wheel to help me find it about a month after i installed it i was just pulling into my yard when the rail pressure jumped from 7,000 to over 30,000 i got out and left it running and got someone to set in the truck and watch the gauge while i moved wires and taped on things, it was a improperly crimped terminal on the plug for the fca, problems with prv, injectors or tubes is best looked at with a leak down test the first few i did was without the miller special tools if you take it out in the middle of a field and have the time you can do it but for a hundred dollars it makes it easier and not nearly so messy, the tools you need is miller#9011, 9012, 9013, and 9014 there is a 4 part video on youtube explaining the cr on the forth part i think is where the how to is at if you do not find it let me know and i will look it up