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Coolant Sensor “Temp” Fix with NO CEL on

3879 Views 31 Replies 11 Participants Last post by  Two Yeets
Hopefully this will help one of you!
Just hit 34,000 on 2019 Cummins, driving home, check engine light came on, followed by “reduced engine power warning”, pulled over, scanned OBDII, and got code P00B7 (coolant level too low).
1) checked coolant level and it was at the correct level
2) pulled the wiring harness plug off of the coolant level sensor on the bottom of the overflow tank
3) used scanner to clear code P00B7 so “reduced engine power warning” and check engine light goes away and you can drive home like normal….ish! No issues while driving
4) got home and the check engine light comes on again, code P2559 (coolant level sensor plug disconnected). Not a big deal, because this code will not trip the “reduced engine power warning”
5) called the dealer, they ordered a new overflow tank/sensor for me, will be delivered in a week
6) in the mean time I didn’t want that pesky check engine light on so I did what the technicians are trained to do at the dealership to get your truck back on the road until the coolant tank comes in (temporary fix)
7) disconnect and remove the passenger side battery (disconnecting both batteries terminals is a safe practice to follow)
8) disconnect the harness plug from the coolant level sensor at the bottom of the coolant tank again
9) now, push up on the bottom of the sensor ever so slightly, and at the same time, rotate the sensor 1/4 of a turn clockwise (the sensors plug end should be facing the front bumper this point), then pull straight down and the sensor will come out, it will be loose and just sitting there against the metal bracket below it (you will not be able to take out the entire sensor, it will just rest there)
NO COOLANT WILL COME OUT REMOVING THIS SENSOR, SO DON’T WORRY ABOUT THAT
10) rotate the sensor back 1/4 of a turn counter clockwise and re-install the harness plug back on the coolant level sensor and just let the sensor sit on the metal bracket below.
11) install passenger side battery, connect battery terminals, and use scanner to clear the check engine light code P2559
12) you should no longer have any CEL’s on the dash at this point, and they shouldn’t reappear while you are waiting for your new coolant overflow tank to come in.
The end!
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Pretty much. Unplugging it gives a "circuit high" code, and doesn't limp the truck. A sunk float, which I belive is what causes this problem for so many of us, will make it believe you're damn near out of coolant, and limp the truck. Dropping the sensor will tell the ECM that you're all good, since the float will be at an acceptable level relative to the sensor. You just won't have a warning if you leak coolant and get too low. Not a huge deal, since you could just check your fluids in a minute while you pump fuel.
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Pretty much. Unplugging it gives a "circuit high" code, and doesn't limp the truck. A sunk float, which I belive is what causes this problem for so many of us, will make it believe you're damn near out of coolant, and limp the truck. Dropping the sensor will tell the ECM that you're all good, since the float will be at an acceptable level relative to the sensor. You just won't have a warning if you leak coolant and get too low. Not a huge deal, since you could just check your fluids in a minute while you pump fuel.
Exactly! If mine wasn’t covered under warranty I would have done this and never fixed it
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I know YouTube is Gospel and all true, but I saw a video today that said if you were stock and drove repeatedly with the faulty sensor P00B7 your truck can’t regen and you’ll plug up your exhaust filter. Apparently that sensor aids in the exhaust system running efficiently. Anybody else heard of this?
Being that a stock truck with that code will go into limp mode, you're probably correct.
Being that a stock truck with that code will go into limp mode, you're probably correct.
But it won’t have the code if you just slide the sensor down. There’s absolutely no way I would think that would affect regen,
But it won’t have the code if you just slide the sensor down. There’s absolutely no way I would think that would affect regen,
Had a look in the calibration. Apparently there is both engine shutdown and engine derate tied to coolant level. The coolant level sensor, derate and shut down could be disabled in the calibration however.
Hey guys I got P00B7 today 140k on the truck 🛻. Pull the sensor down unplugged it and cleaned it put it back in and cleared the code and check engine light don’t come back on so I think it’s the tank. Was thinking about getting one from cft how would it work with the sensor?? Thanks
I’ve got almost 207k on the truck and it’s been having coolant issues for 50k. Usually I just add some and be done with it. Now it’s at appropriate levels and I’ve got the reduced power warning that won’t go away. May try this “fix”.
Anyone have the part number for the newer tank that’s been “improved”?
This is the part number from the warranty repair invoice from Nissan which is the newest part number:
21710-ez40a
A rock hit my rad and coolant emptied. I fixed it with JB weld on the side of the road, only problem was it went into low power mode. You can just unplug the sensor and you wont be in low power mode and drive home with the engine light on . Mines stock and made it home in the steepest mountains in BC.
A rock hit my rad and coolant emptied. I fixed it with JB weld on the side of the road, only problem was it went into low power mode. You can just unplug the sensor and you wont be in low power mode and drive home with the engine light on . Mines stock and made it home in the steepest mountains in BC.
Where in BC?
A rock hit my rad and coolant emptied. I fixed it with JB weld on the side of the road, only problem was it went into low power mode. You can just unplug the sensor and you wont be in low power mode and drive home with the engine light on . Mines stock and made it home in the steepest mountains in BC.
I'm about to throw keep some JB weld in my toolbox after reading this.
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