20A201 code thrown...never got a low coolant warning...thoughts?

[FAKE__NEWS]

Hey y'all - my car is just out of warranty and this morning I washed the car and went to fuel it up. Started it back up and it threw a drivetrain malfunction. The car is running a Stage 1 93 oct BM3 tune so my first thought was, "shit, it's the crankhub." Shut the car down, plugged in my WiFi agent and ran the codes and 20A201 was thrown in addition to a couple others (ASD disabled, and a short in my KAFAS camera heater).

I've done a few searches on the forums and so I have a pretty good idea that my top mount intercooler is shot. Waited until tonight and checked the reservoirs. The car was on a bit of an angle but the intercooler reservoir is way low, engine coolant reservoir was low but not by much.

I'm not smelling anything, not seeing any white smoke and the car never threw a low coolant warning.

My question is: is there anyway to self diagnose this without pulling the intercooler off? The car is going in for an oil change on Monday, should I just bite the bullet on the diagnostic cost and have them diagnose it?

Thanks!

[Andrew M]

Been getting the same thing. My car is out of warranty also. No coolant message came up or anything and have driven car a little while before I had my friend plug in a scanner ( more advanced than obd2 ) and that was my major code. It was 20A201 and I checked my coolant reservoir and it was empty. I think the best thing is to have a pressure test done to see if there is a leak somewhere.

[rome5982]

I just hit 52K miles on my 2016 M3, just got the "Drivetrain Malfunction: Drive Moderately. Maximum drivetrain output not available".

Checked the intercooler and it is dry. Checked codes and I have 20A201 (auxillary coolant pump for charge air cooler coolant. Loss detected in coolant pump). I checked the level last week (by chance) and it was good. So I think it happened suddenly. Im going to check to see if it is something obvious with a line leak or the aux pump before I assume its the intercooler.

Can either of you update this thread with what was found and corrected for your situation? Thanks

[rome5982]

Update - I found the problem. Small puncture leak in the front heat exchanger radiator for the intercooler coolant. I started to refill the reservoir and it started gushing without the auxiliary coolant pump even running. Even if I was still under warranty they would not have covered this. Looks like I'm shopping for a new heat exchanger. I will check with the dealer tomorrow with my CCA to see how much the part is (confirmed part with CCA is $349). The only one I see aftermarket is the CSF one for ~ $700.

[parky1215]

I am also having this specific issue on my 2015 M3 with 52k miles.
No CEL, but I saw this hidden code from BM3 diagnostic page.
When I checked coolant it was totally empty.
I filled up full, but it would slowly decrease every week when I check it.
I am pretty sure that I have slow leak somewhere inside intercooler as I do not see any leak coming from radiator as the poster right above me.

I ordered replacement intercooler and will be replacing it myself when it arrives.
It seems pretty easy to replace this from online video I saw.

[Gotulukn]

Originally Posted by parky1215

I am also having this specific issue on my 2015 M3 with 52k miles.
No CEL, but I saw this hidden code from BM3 diagnostic page.
When I checked coolant it was totally empty.
I filled up full, but it would slowly decrease every week when I check it.
I am pretty sure that I have slow leak somewhere inside intercooler as I do not see any leak coming from radiator as the poster right above me.

I ordered replacement intercooler and will be replacing it myself when it arrives.
It seems pretty easy to replace this from online video I saw.

Hey did this fix your problem? Is there a chance it could be the auxillary pump itself? Or it usually is the top mount intercooler?

I've been stage2 93 octane for about a year, I went e85 2 weeks ago. Then now i have this same code "202a201 auxiliary coolant pump for charge air cooler: Coolant loss detected"