Water Pump constantly running N55 F16 2015

[theomajigga]

Heya,

2015 F16, BM3, upgraded charge pipe. Did have to open up the DME for a bench unlock. Problem started about 4 days later, so I don't think it is related but wanted to post all details)

Had a bad battery, swapped the battery, registered it, no issues for a day, again don't think this is relevant, but wanted to post it all.

Codes thrown (all at different times, but one persistent)

CD8E10 (persistent)
CD8E12 (generator not communicating)
CD9010
215001 (IBS, probably when I had it unplugged)

Scoped the lin bus at the IBS seemed to be normal, scoped the lin bus at the waterpump with the pump unplugged and it also seemed normal there. Couldn't get a clamp around the line when it was plugged in, so that is when I went to the IBS to scope it there. Again didn't see any issues with my untrained eyes, seemed to have communication on the line.

Pump doesn't "stick" on when the lin bus is active. Seems to be running normally. As soon as the lin bus falls asleep, the waterpump powers up and will run until the battery is dead.

Can get it to shut off by hitting anything on the remote, car, etc (since it wakes up the lin bus). But again, as soon as the bus falls asleep, it powers up.

My guess is the waterpump is not following the sleep command, or whatever, except that when the car is awake, it doesn't run (unless it needs to) so that is why I'm a little confused.

Can anyone give me any insight? From what I've read, this is a thing that has happened before, but I am just looking for some confirmation before I go and buy a pump.

Thanks all!

[scotty339]

Whats the ODO at? Seems like you need a new water pump.

Maybe try running the water pump bleeding cycle, maybe that will trigger something and cause it to reset?. Its activated by holding the gas pedal to the floor for 10 sec or so. (easy enough to find)

[theomajigga]

Originally Posted by scotty339

Whats the ODO at? Seems like you need a new water pump.

Maybe try running the water pump bleeding cycle, maybe that will trigger something and cause it to reset?. Its activated by holding the gas pedal to the floor for 10 sec or so. (easy enough to find)

13x.xxx I'll give that a go tomorrow.

Weird thing... Tonight when I plugged it in to bring it to my buddies shop, no issues for the time I plugged it in, to the time I stopped at his house. Parked it, no problem, no codes.

Moved it to the shop, and the pump started up again, and wouldn't shut off.

[scotty339]

130,000 miles? Original pump?

100,000 is normally the limit for the N55 pump.

[theomajigga]

Can't say, just bought it. I would imagine, as it seems like it's got the same tarnishing on it as the rest of the block. Just a super weird failure mode.

[theomajigga]

Just wanted to update, because no one ever does.

Parked it and it was fine for a few hours. Went outside to grab my laptop and it was running again.

Used some good ol' percussive maintenance (READ: BFH) and it shut off again. I will be installing a new water pump tomorrow, so this issue should be considered resolved.

Will update if something new happens.

[tlow98]

Thanks for the update. Incredibly rare situation will surely helpful for others.

[rijotech]

Originally Posted by theomajigga

Just wanted to update, because no one ever does.

Parked it and it was fine for a few hours. Went outside to grab my laptop and it was running again.

Used some good ol' percussive maintenance (READ: BFH) and it shut off again. I will be installing a new water pump tomorrow, so this issue should be considered resolved.

Will update if something new happens.

Was you able to fix your problem? I’m facing the same situation.

[Clifton]

Originally Posted by rijotech

Was you able to fix your problem? I’m facing the same situation.

If you recently changed your battery and found your water pump runs beyond normal cool down cycle, you most likely shorted the pump during the battery swap.

There are a few threads (Read thread but see post #34) discussing this and the conclusion is that the power to the water pump remains active after vehicle is turned off even without the key. If the battery is swapped before the car fully goes to sleep (hazard light no longer illuminated), you can short the water pump and it will continue to run going forward.

Only real fix is to replace the water pump.