Turbo coolant pump issue?

I read somewhere that once coolant system has been touched this is pretty much air in the system. I dont think these bleed like the previous generation which requires holding gas pedal 10 seconds and it does it on its own, can you find put how?

You’re right on the target area, 20A503 is for the turbocharger auxiliary coolant pump circuit-self-diagnosis, not a normal engine misfire or fuel code. It can trigger a drivetrain malfunction message without a check engine light.

Since the oil filter housing was just replaced, I would first recheck the connector and wiring at the auxiliary/turbo coolant pump. Next, I would check the 5 amp fuse #2 that runs the pump inside the intergraded supply module. It is only 5 amps so when the pump goes out it pops easily. Let us know how it goes. What do you think of the new site design?

I see. But i didn't touch the pump when i replaced the oil filter housing. They are far apart from each other. Also replaced it with a used one oem. This pump supposed to cool the turbo after you shut off the car, but even if i start the car for couple of minutes the message comes on after you turn off the car which fuse box the one behind the glove box. The site is good but overwhelming, alot more stuff and tabs. A d i get logged off anytime i leave it for few and have to login then go dashboard, but looks much better

Number 2 fuse has a dummie fuse i replaced it but looks like there are no connections there. Can you recheck. Number 2 is in the e trunk by battery

I tried the bleeding procedure by pressing gas pedal 10 seconds, while heat is on, heard the main pump come on but no water or bubbles came out of either reservoirs like I used to see it on older models. Both reservoirs are full. Everything indicates a large air pocket or another dead pump, which was used, how do I go about checking the 3 wires for the pump's harness?

You may have blockage inside the turbo not allowing the coolant to flow. The fuse panel should be under the hood for the #2 fuse. Here is the wiring diagrams for the turbo water pump. Check out the images (below). Let us know how it goes

The fuse panels is not numbered. Any way u can find out which one is #2?

Only fuse i found burned is the one am pointing to which is a 20 amp fuse. Replaced it and now bleeding it again. I can feel the water in the hose coming out of the turbocharger coolant pump moving but i barely see any bubbles ir anything coming in any of the reservoirs

This one

One wire is positive one is ground and i guess the 3rd is sent by ecu when needed so i cant check it. Not sure if the used pump is bad or something else. But i felt the water gushing theough the hose coming out from it. But it could be that the main electrical water pump when doing the bleeding is the one pushing this water around

Is there a way to test and see if this pump is working while its on ? Also since this pump only works when the engine shuts off i guess will it pump everytime i turn car off? And does the car need to be at optimum temp or even when cold and turned of after it is started for a short period

Based on what am seeing online this gas a belt driven water pump not an electrical which makes no senseZ so what is running while i hold the gas pedal down and i hear it go and stop for few then starts again, it felt like its similar to the ones from previous years. Weird. Possible a weak pump from when it was leaking and just ran and ran low on fluid?

Also noticed when i try to delete the code it keeps giving me ecu error rejected. Never seen that before

Yep, the fuse is a 5 amp unit so it doe not look like the fuse you are pointing too. You should be able to ground the white wire and brown wire, then put 12 volts tot he red/grn wire and the pump should run. You should check to make sure there is no blockage in the cooling lines as well.

I doubt there is a blockage. Car does not over heat at all

Okay, let me know if the pump runs and if you find the right fuse.

I cannot find a diagram showing which fuse is #2 but all 5am fuses are good. There are 2 grounds showing with the probe. Ill have to find a way to do 3 wire jump while harness is connected its a tight space

You can see the fuse in the wiring diagrams above.

Oh, where it says 1 thats fuse 1? Thought it has to do with the diagram labels or they were pointing to something

It is fuse #2 in the fuse box. Just check all 5 amp fuses.

Contacted a friend who has alldata abd he said he repaired the ivm on manyof these. Has a non replacable fuse. I remember i did too on an older bmw which fixed power to the main electric pump not this one but ill check. But he sent me 2-3 different locations. Is the one under the hood like u mentioned where the fuse is tbh e one to look at?

If you turn the car on does the red/grn wire at the pump have power to it?

Let me check. Thing is i don't know or think that it would have a constant power or it gets triggered by a relay. I heard that an ecu only provides ground, not power, so i would assume there is a relay that gets a message from the ecu when needed only to turn it on, e.g. after the car gets to optimum temp and turned off or at all time while car is running

YEs, the ECU grounds the circuit, the pump fuse gets is power from the DME control relay, please check out the wiring diagram above.

OK 2 QUESTIONS. The fuse for the turbo charger, does it only control the pump ? Also, the fuse is within the big fuse box under the hood correct? not the one in the trunk or the IVM by the fuse box under the hood which has no fuses, but rather have 3 connectors. The guy said there is a non serviceable fuse, and since there are so many fuse boxes I gt confused

Yep, that is why I wanted to test the power at the pump with the system on. The DME relay controls many things, why do you ask? Lets find out if the coolant pump has power first.

With ignition off the red and blue is ground, nothing on other 2 wires. With ignition on red and blue becomes power. White one is ground. With car running. With car running same as with ignition on. Nothing on the brown wire

Attached

ALSO SEEN THAT SOME OF THE YEARS HAVE THE TURBO COOLANT PUMP UNDER THE INTAKE WHICH IS WHERE THE OIL FILTER HOUSING IS. BUT ON MINE ITS RIGHT IN FRONT OF THE ENGINE, AND THE ONE UNDER THE INTAKE LOOKS BIGGER, WHICH IS WHAT I RECEIVED WHEN I ORDERED FROM AMAZON AND THEN RETURNED IT. SO CAN YOU SEE IF THE 2018 330I HAS IT UP FRONT OR UNDER THE INTAKE? HOPEFULLY THERE IS NOT ANOTHER ONE UNDER THERE, WHICH I DOUBT

Check this plz

Okay, the wiring seems okay so that is good, since you changes the pump out I would check/change out the coolant pump change over valve. Here is the location. Here is the location.

ok I remember this valve, hopefully I just forgot the connector off and I remember two vacuum hoses maybe switched them. This is next to the oil filter housing. what does this do?

also, isn't the 3rd wire supposed to have power or ground?

No, that is the sense wire, it will vary and is commanded by the ECU.

What is the job of this valve

Removed the i take again, no pinched or loose wires. Removed this change over valve. Any way to bench test it? Just ground and power? Also any idea if it could have a fuse?

Also there is a power module by the ecu that i remove when taking intake out. Looks like this one in the picture. I opened the bottom slightly and saw fuses. Can you see if this change over valve has a fuse as well or where it gets power from. Also since it only has 2 wires, how does it come on without a 3rd signal, cant be coming on all day. And by the way pictures load up super fast now compared to previous site

I looked up the number on the part you told me about and it says its a boost pressure and egr vacuu
Solenoid valve

I saw the main water pump, which is mechanical, and it has on the side something like an adjuster. I pushed the adjuster using the arm and it creates a vacuum fine and then that small pump that creates vacuum has a vacuum hose, which goes to that piece i removed. It looks like this in the picture

After I removed the intake again, looked and looked and found that the main big harness that feeds pretty much everything going up to the engine has a 10 mm bolt to bolt it to the engine. It turned out to be a ground, even though there is plastic bracket around it. Now the bleeding starts when I turn the ignition on and hit the gas pedal for 10 seconds. It took 12 minutes like I know it from before. Only thing is that the driving malfunction message keeps popping up after you turn the car off. No check engine light or codes.