Quote:
Originally Posted by premo
The pump is located on the left side (driver side in USA). It cycles coolant around the system when you are stopped. It is also used for coolant flushing. After draining the coolant, if you refill the coolant and with the ignition on, put the heat on highest temp and lowest fan and setting, it will turn on and cycle the coolant through the car to get air out of the system. To engage this mode, you must have heat on highest temp, fan on lowest setting while car is off, then hold the gas pedal for 10 seconds. After this the aux pump will turn on and cycle the coolant. This will continue for some 10-12 minutes and you'll be able to hear it also. Make sure not to close your driver door, as that will shut off the sequence. The aux pump helps bleeding without starting the car, since the main water pump, is belt driven. It also turns on when driving and when the car is stopped.
If you have this code, you can buy a second hand one from eBay. I had this error as well. I bought one from eBay or around $35-$40 US. Super cheap, new it will cost around $200 +. I suggest changing it if you can. It shouldn't hurt anything to not change it though. You won't really notice a difference.
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Thanks Premo. This is the way I understood its "function" but still confusing as:
1) Coolant is even according to BMW TIS suppose to be selfbleeding, aux pump is not mentioned to be used?
2) After the Rest button was taken away 2010, the only way to get the residual heat would be to have ignition on? Can't see that happen often, especially as the function isn't described anywhere?
Btw I've tryed mentioned trick to start the pump, nothing happened so yes seems dead, not surpricing as its probably never been on during its 9 years..
. You actually performed this on your M3? (I've seen it works on standard 3 series but obviously using their electrical main coolant pump).
I've checked the pump and can see its an easy replace, but would like to better understand why first...
