[MrrMaxime77]

Hello everyone,

I write you from France (sorry for my bad English sometimes), I have a problem with my 335i E93 N54,
I read many post here and on other forums but can find my problem.

My radiator was cracked and WP leaking.

I just change this weekend, radiator, WP, Thermostat, temperature sensor. But impossible to start the bleeding process

Ignition on
Heat at maximum
One bar speed
Press gas pedal for 10-12s

Nothing happen.

So I try to bleed it manually just let running engine, but not good car overheat very quickly.

I do many test, Check voltage in distribution box I read 12.20v on each cable
I check the big fuse in the dme OK
Check voltage at the WP plug
I have on the for 4 pin
12V
12V
7V
0V
So seems to be good

Do you have an idea of what can be the problem ?
Which cable and log can I buy to reads code and maybe activitate WP to check it ?

Greetings from France!
Maxime

[Steve Sas]

The pump should start running using the bleeding process.
Suggest checking 12v under load with 50w light globe at the WP connector.
There as an issue with corrosion on power supply terminal to WP near battery in the boot.

https://www.e90post.com/forums/showthread.php?t=951371

[Mcnelly]

I'm not sure if you figured the problem out yet. But for me I was chasing a overheating problem. Replaced pump and thermostat but still over heat. Replaced the whole harness and checked all fuses.

The only solution I found was this jumper wire going from the red to orange wires.. those wires power the pump.
Connectors under battery are clean and clear and no clue where to look for the short

Hopefully this helps you as well

[MrrMaxime77]

Helloo all,

I was not turn on reply notification so I thought no one answer me !!
I just check it today my post and see answers Sorry and thanks for reply

I still in the same situation with my car, I am towing it tomorrow TO a shop..

You talk about corrosion and check with a light
But I already check the 4 pins with multimeter and read :
12V
12V
7V
0V
This is good or not ?

This afternoon I will try to jump this green plug as you did.

Any one have other ideas ?

Thanks again, I was disappointed to think I get no answers from US guys. Normally I always find help and good advice.
I have a C5 convertible year 00 and I am on CorvetteForum

US people are always better even on Europ car as BMW 😚

[MrrMaxime77]

It seems to be UK people are also heree !! Glad to speak and learn from United Kingdom 😍

[MrrMaxime77]

My electric box is like that and the green connector not like yours .. do yo know which one powered the WP ?

[e91Owner]

On your first post, you said that you let the engine run. Did you confirm that the pump is actually coming on with the engine running? If it will not come on during the bleed procedure, it will likely not come on with the engine running either. If you leave the cap off on the expansion tank and turn the engine on, you should see when the coolant starts to flow.

Also, if I understand you correctly, you were asking about a code reader. For something simple like this, I recommend Carly.

https://www.mycarly.com. You can find them on eBay.fr, maybe cheaper directly through them, though as they are in Germany.

The simplest solution is that the connection to the pump is not fully seated.

[MrrMaxime77]

Hello, I confirm the pump is not running when the engine is on.
If I leave the cap off, nothing happen until coolant overflow when become hot.

I bought a cable K DCAN with inpa and ista D but hard to communicate with the car I dropped.

Unfortunately I also think maybe I don’t plug it very well so I go back under the car to check it. This is at this moment I also check for voltage on the 4 pin.

Just to know : When you start the engine the water pump begin to start at which moment ?

I bring my car to a shop today where the guy have and love bmw so I will see. He will begin to diagnose it and we will see..

Originally Posted by e91Owner

On your first post, you said that you let the engine run. Did you confirm that the pump is actually coming on with the engine running? If it will not come on during the bleed procedure, it will likely not come on with the engine running either. If you leave the cap off on the expansion tank and turn the engine on, you should see when the coolant starts to flow.

Also, if I understand you correctly, you were asking about a code reader. For something simple like this, I recommend Carly.

https://www.mycarly.com. You can find them on eBay.fr, maybe cheaper directly through them, though as they are in Germany.

The simplest solution is that the connection to the pump is not fully seated.

[e91Owner]

The pump does not start running until it is required, but it should turn on nearly immediately if you have the heat selected on in the car when it is running.

[MrrMaxime77]

Ok, my pump never turn on. Conséquence even with heating at maximum speed level one or max I have no movement of the WP and no heating on the car.

[e91Owner]

D'accord, sans connaître les codes de l'ISTA, c'est vraiment juste une supposition sur le problème. Espérons que le mécanicien pourra lire les codes et vous donner une meilleure réponse. La chose la plus simple à faire est simplement de s'assurer que la pompe est correctement connectée. Si l'ancienne pompe fonctionnait, il est peu probable que ce soit un problème électrique.

[MrrMaxime77]

Originally Posted by e91Owner

D'accord, sans connaître les codes de l'ISTA, c'est vraiment juste une supposition sur le problème. Espérons que le mécanicien pourra lire les codes et vous donner une meilleure réponse. La chose la plus simple à faire est simplement de s'assurer que la pompe est correctement connectée. Si l'ancienne pompe fonctionnait, il est peu probable que ce soit un problème électrique.

Actually on a shop, he told me my FRM module have a problem and said it powered the pump... do you confirm this is the FRM or the DME who powered the pump (as I read)

Thanks

[e91Owner]

Originally Posted by MrrMaxime77

Actually on a shop, he told me my FRM module have a problem and said it powered the pump... do you confirm this is the FRM or the DME who powered the pump (as I read)

Thanks

No, the FRM controls the lights. Most FRM problems are indicated by not being able to turn on your directional signals. I don't see how any failures in the FRM would have anything to do with your water pump.

Here is the operational description of the electric pump controls from ISTA:

Operating principle
The coolant pump of engine N52 is an electrically driven pump. The power output of the electric motor is controlled by a control electronics circuit. This control electronics circuit is connected via the bit-serial data interface with the Digital Engine Electronics (DME). The DME uses the load, operating range and the data of the temperature sensors to determine the required cooling power. The DME issues the corresponding control signals for control of the coolant pump to control electronics circuit. The coolant pump's motor is flushed with coolant. This lubricates the bearings of the electric coolant pump.

[Steve Sas]

Not 100% sure but read somewhere that the bit serial data line can stop working when another device on the bus is faulty like the oil level sensor or battery voltage sensor.
Both of which use same interface.

FRM may have bit serial data. A good tech should be able to diagnose fault fairly quickly as these E9X cars have been around for a while and should be well known.

[MrrMaxime77]

Fault Code (Présent)
2E84

Maybe my new water pump is defective... what you think ?

[e91Owner]

Originally Posted by MrrMaxime77

Fault Code (Présent)
2E84

Maybe my new water pump is defective... what you think ?

The FRM faults look like they are caused from when your battery died or was disconnected and should just clear when you clear the faults.

Have you cleared them? Before testing anything further with the pump, I would clear them, start the engine, shut it down after a few seconds and scan for codes again. If you are still getting 2E83, 2E84 & 2E85, you will need to check the fuses in the E-box. If those are all good, you need to check the voltages on the wires. If you search for those errors, you will find the correct voltages for each wire.


That being said, all of this is something that I would expect your mechanic to know as the water pump on N52s is a very common failure.

[MrrMaxime77]

My engine is N54

You said right !! My problem was on the eBox : a pin in a plug was bent !! He just re tend it. Bleeding process OK, coolant flow ok. No more overheating

Now I have a problem with my alternator but not important regarding to this strange issue !!

Thanks to all

[Steve Sas]

Why would a pin be bent in the eBox?