[88atlas07]

2011 e90 N55, 138k miles

Currently getting the 00348F code-Map-Controlled Thermostat, control short circuit to ground.

I got the car several months ago from Copart as a rebuild project, it had taken a decent hit to the pass front suspension among many other issues. Got the car all sorted and the last thing on the list of issues is the water pump turning on whenever the car is shut off, or whenever the car is locked/ unlocked. It will run for several minutes until the car goes to sleep, and then the pump stops. Hit the key and it turns right back on for another cycle even if the car is cold.

Searching this issue, many solved the problem with a new water pump/ T-stat. I tried 2 new water pumps and 1 new thermostat with the same issue present. I've ordered a new coolant temp sensor that Ill try tomorrow but doubt that'll do anything.

I've also cleaned the ground on the driver's side engine mount, the same issue continues

Unplugging the thermostat or Water temp sensor does not stop the pump

I did have an unsolvable BST 0093B2 code that I couldn't reset, even after replacing the cable, as well as trying the 2ohm resistor bypass to no avail. I then left the BST harness unplugged and it cleared the light and the car passed inspection so given that the BST and water pump are all on the same BSD Bus, that may be a clue.

Running out of ideas, Later in the week I'm swapping in a new HPFP so will have the intake off and can trace the water pump/t-stat wiring to look for any fraying but for now, I'm stumped.

[88atlas07]

Does anyone have a wiring diagram for the thermostat/water pump? Still haven't figured it out

[TunafishE93]

Goes from thermostat to front of engine right below valve solenoid to DME.

[88atlas07]

Thank you!

[88atlas07]

Was replacing the HPFP so had the intake off anyway so peeled all the wires back to check for damage. Found the thermostat wiring to have chafed through and probably grounded out on the block. Waiting on gaskets to put it back together so won't know for sure for a few days, but don't see anything else that it could be.

[TheMidnightNarwhal]

How long was your running? I'm trying to find if I have an issue, I noticed mine runs like 15 mins after still. But I don't have codes. I did replaced battery but it was the factory one from 11 years ago but maybe now the pump running killed it.

[88atlas07]

It'll run for about 10 minutes, and once the car goes to sleep it shuts off. If the car wakes up by unlocking or opening a door the pump stays on until the car goes back to sleep.

Weird thing is that with the ignition on and engine off, the pump stays off. Turn ignition off and the pump turns on. No codes...The short circuit code was for the frayed thermostat wire which I replaced but that did not solve the pump issue.

[TheMidnightNarwhal]

Originally Posted by 88atlas07

It'll run for about 10 minutes, and once the car goes to sleep it shuts off. If the car wakes up by unlocking or opening a door the pump stays on until the car goes back to sleep.

Weird thing is that with the ignition on and engine off, the pump stays off. Turn ignition off and the pump turns on. No codes...The short circuit code was for the frayed thermostat wire which I replaced but that did not solve the pump issue.

Oh wow ok, mine did not wake up I think when unlocking the car after it sleeps.

I guess mine is normal. Sucks your wiring did not fix it.

[afy511]

Originally Posted by 88atlas07

It'll run for about 10 minutes, and once the car goes to sleep it shuts off. If the car wakes up by unlocking or opening a door the pump stays on until the car goes back to sleep.

Weird thing is that with the ignition on and engine off, the pump stays off. Turn ignition off and the pump turns on. No codes...The short circuit code was for the frayed thermostat wire which I replaced but that did not solve the pump issue.

Did you find the solution?
I have the same issue.

[X4 35i_NOLA]

Im having the same intermittent working of my my water pump.

It’s more like. Short…works after turning the car on with nothing other than restarting the car until it decides to turn on. I ran through some water and it started happening that day.