[Antetokounmpo]

I've been getting this code for a month or so now and after driving for about more than 30 min, the cooling fan will come on full blast and the throttle goes into a limp mode. I haven't really found anything on a solution for this. Water pump is new 30k miles ago so its not overheating. The coolant temp will be normal at 210 when it comes on then go down to 170 when its on full blast. It seems weird to replace the fan when it's seemingly working perfectly.

[IISevv]

The cooling system along with a few other electrical components all talk over the same signal bit connection. If there’s a problem with one, it can cause communication faults along the line. And, the fan doesn’t just come on when coolant temps get too high. It’ll also come on if it detects a fault in the water temp or thermostat signal.

[Antetokounmpo]

Originally Posted by IISevv

The cooling system along with a few other electrical components all talk over the same signal bit connection. If there’s a problem with one, it can cause communication faults along the line. And, the fan doesn’t just come on when coolant temps get too high. It’ll also come on if it detects a fault in the water temp or thermostat signal.

Right, that's why it doesn't make sense to replace the fan. I have no other codes for coolant sensors or anything though.

[PichaDis11]

The issue may still be your fan. The Fan is capable of running at different speeds. It's abnormal for it to run full speed all the time when its on. Except when the A/C is on. you can test this out using the INPA software.. tests are 50%, 75% & 100%. If it fails to operate at 50% or 75% then you will know that the fan is failing.

[gbalthrop]

Originally Posted by Antetokounmpo

I've been getting this code [2EFF] for a month or so now and after driving for about more than 30 min, the cooling fan will come on full blast and the throttle goes into a limp mode. I haven't really found anything on a solution for this. Water pump is new 30k miles ago so its not overheating. The coolant temp will be normal at 210 when it comes on then go down to 170 when its on full blast. It seems weird to replace the fan when it's seemingly working perfectly.

QUESTIONS:
1) Any warning light or SES when the code is set?
2) Are you monitoring coolant temp (ECTS signal to DME) either with PID readout or using Hidden Menu 7.00?
3) Is coolant temp OK as long as you are moving?
4) When it "goes into a limp mode" is ANY warning light or SES lit?
5) Does it leave "limp mode" on its own when temperature drops, or do you have to delete code?

The fan motor may be working perfectly, but apparently the fan control module (which is integral with fan unit) is NOT, OR you have an issue in the connector or wiring.

Here is what Bentley says about that code:
P14CO | 2EFF | Fan Mechanical Hardware Defect

Here is what Bentley says about fan self-test on startup:

"When the vehicle is first started, the ECM activates the electric fan
briefly at 20% of its maximum speed, then switches OFF. This is for
diagnostic monitoring. The voltage generated by the fan when it
slows down (acting as a generator) must match the stored rpm
values in the fan output stage to confirm that the fan is operating
correctly."

If you have INPA/ISTA, you can do some diagnostics on the fan, using Activations as stated above. If you do NOT have that software, but can read & clear the 2EFF code, you can do this:
Clear the code. Have someone else start the engine while you monitor fan operation. See if fan runs @ 20% max speed for ~ 10-20 seconds. Look for any warning light or code.

If either the fan never ran, or it ran and then set the code again, you have some further evidence of the nature of the issue.

George

[Antetokounmpo]

Originally Posted by PichaDis11

The issue may still be your fan. The Fan is capable of running at different speeds. It's abnormal for it to run full speed all the time when its on. Except when the A/C is on. you can test this out using the INPA software.. tests are 50%, 75% & 100%. If it fails to operate at 50% or 75% then you will know that the fan is failing.

I've been trying to get INPA to work on my new laptop. I had it on my old laptop but I can't remember how I got the ports to work in the virtual machine.

Originally Posted by gbalthrop

QUESTIONS:
1) Any warning light or SES when the code is set?
2) Are you monitoring coolant temp (ECTS signal to DME) either with PID readout or using Hidden Menu 7.00?
3) Is coolant temp OK as long as you are moving?
4) When it "goes into a limp mode" is ANY warning light or SES lit?
5) Does it leave "limp mode" on its own when temperature drops, or do you have to delete code?

The fan motor may be working perfectly, but apparently the fan control module (which is integral with fan unit) is NOT, OR you have an issue in the connector or wiring.

Here is what Bentley says about that code:
P14CO | 2EFF | Fan Mechanical Hardware Defect

Here is what Bentley says about fan self-test on startup:

"When the vehicle is first started, the ECM activates the electric fan
briefly at 20% of its maximum speed, then switches OFF. This is for
diagnostic monitoring. The voltage generated by the fan when it
slows down (acting as a generator) must match the stored rpm
values in the fan output stage to confirm that the fan is operating
correctly."

If you have INPA/ISTA, you can do some diagnostics on the fan, using Activations as stated above. If you do NOT have that software, but can read & clear the 2EFF code, you can do this:
Clear the code. Have someone else start the engine while you monitor fan operation. See if fan runs @ 20% max speed for ~ 10-20 seconds. Look for any warning light or code.

If either the fan never ran, or it ran and then set the code again, you have some further evidence of the nature of the issue.

George

Thanks for the reply. I'm trying to get INPA to work on my virtual machine but its a PITA.

1) No warning lights, I can only see it through MHD
2) Monitoring coolant temp with MHD as well
3) Coolant temp is steady at 210F until the fan turns on, then it goes to about 170F
4) Still no warning lights when it goes into limp
5) It leaves limp mode when the fan goes back to normal (temp goes down to 170)

The fan does run when I start it and the code doesn't come back right away, I'll have to see for sure today after work how long it takes to come back. I cleared it then fired it up and let it idle for about 2 minutes and the code didn't come back in that 2 min.

[gbalthrop]

Originally Posted by Antetokounmpo

I've been trying to get INPA to work on my new laptop. I had it on my old laptop but I can't remember how I got the ports to work in the virtual machine. [If you have a Windows 10 laptop, it should just be straight install, NO virtual machine?]...
3) Coolant temp is steady at 210F until the fan turns on, then it goes to about 170F
4) Still no warning lights when it goes into limp
5) It leaves limp mode when the fan goes back to normal (temp goes down to 170)...

As suggested by IISev, it sounds like you have some type of communication fault in the BSD (Bit-Serial Data) bus, or other issue with DME control of Coolant Pump and/or Thermostat. If you are cruising at 50+ MPH, there should be enough air flow through the radiator that the fan is NOT needed, and the fan coming on (ONLY that) should NOT cause the actual coolant temp as detected by the ECTS (Engine Coolant Temp Sensor) to drop from 210F to 170F.

If the thermostat, coolant pump, and radiator fan are all functioning properly (along with proper DME control) the Fan should NOT be operating at cruising speed, and its operation should have no effect on coolant temperature. Also if the thermostat is operating properly, you should NOT see temp going from 210 to 170F, but rather it should be in the 190 - 200F range, when cruising, and radiator fan should NOT come on.

It sounds like your coolant pump is NOT operating (at least at high enough speed) until the fan kicks in (for some reason). You don't post your model or year (necessary for correct circuit diagram information), but just guessing from some prior posts, you have a 335i E90, and if it is 2008 or later, then the following schematic applies (drill down and get correct diagram if 2007 or earlier):
https://www.newtis.info/tisv2/a/en/e...ooling/vRilOSj

Start with checking fuse F37 (30A) which powers the control for both the Coolant Pump and Thermostat, and if you can monitor fan speed, pump speed, ECTS temp signal and Radiator outlet temp signal while cruising at steady 50 - 65 MPH, as you can with INPA, then you can probably get a better idea of what is happening.

INPA allows you to MONITOR in "Activations"/ Steuern (F6) BOTH (1) Thermostat opening position, and (2) Coolant Pump speed (as percentages of max), along with ECTS Temp Signal and Radiator Outlet Temp Signal, so that you can see what is going on with the pump and thermostat. That would be the best diagnostic for your wild coolant temp fluctuation (between 210F & 170F). As stated before, if the fan is coming on while cruising, I don't think the FAN is the issue.

George

[Antetokounmpo]

Originally Posted by gbalthrop

As suggested by IISev, it sounds like you have some type of communication fault in the BSD (Bit-Serial Data) bus, or other issue with DME control of Coolant Pump and/or Thermostat. If you are cruising at 50+ MPH, there should be enough air flow through the radiator that the fan is NOT needed, and the fan coming on (ONLY that) should NOT cause the actual coolant temp as detected by the ECTS (Engine Coolant Temp Sensor) to drop from 210F to 170F.

If the thermostat, coolant pump, and radiator fan are all functioning properly (along with proper DME control) the Fan should NOT be operating at cruising speed, and its operation should have no effect on coolant temperature. Also if the thermostat is operating properly, you should NOT see temp going from 210 to 170F, but rather it should be in the 190 - 200F range, when cruising, and radiator fan should NOT come on.

It sounds like your coolant pump is NOT operating (at least at high enough speed) until the fan kicks in (for some reason). You don't post your model or year (necessary for correct circuit diagram information), but just guessing from some prior posts, you have a 335i E90, and if it is 2008 or later, then the following schematic applies (drill down and get correct diagram if 2007 or earlier):
https://www.newtis.info/tisv2/a/en/e...ooling/vRilOSj

Start with checking fuse F37 (30A) which powers the control for both the Coolant Pump and Thermostat, and if you can monitor fan speed, pump speed, ECTS temp signal and Radiator outlet temp signal while cruising at steady 50 - 65 MPH, as you can with INPA, then you can probably get a better idea of what is happening.

INPA allows you to MONITOR in "Activations"/ Steuern (F6) BOTH (1) Thermostat opening position, and (2) Coolant Pump speed (as percentages of max), along with ECTS Temp Signal and Radiator Outlet Temp Signal, so that you can see what is going on with the pump and thermostat. That would be the best diagnostic for your wild coolant temp fluctuation (between 210F & 170F). As stated before, if the fan is coming on while cruising, I don't think the FAN is the issue.

George

George, thank you for the detailed reply. I do indeed have a 2008 335xi. I will check fuse 37 when I get home.

I have a windows 10 machine for work that I could install INPA on, I previously did a virtual machine on my Mac and eventually got it working.

There seems to be way too many conflicting threads on installing INPA on Win 10 x64, do you know of a good thread/install guide that I can follow that worked well? it seems like once I get INPA running again I'll be able to find the root cause.

[Antetokounmpo]

Originally Posted by gbalthrop

As suggested by IISev, it sounds like you have some type of communication fault in the BSD (Bit-Serial Data) bus, or other issue with DME control of Coolant Pump and/or Thermostat. If you are cruising at 50+ MPH, there should be enough air flow through the radiator that the fan is NOT needed, and the fan coming on (ONLY that) should NOT cause the actual coolant temp as detected by the ECTS (Engine Coolant Temp Sensor) to drop from 210F to 170F.

If the thermostat, coolant pump, and radiator fan are all functioning properly (along with proper DME control) the Fan should NOT be operating at cruising speed, and its operation should have no effect on coolant temperature. Also if the thermostat is operating properly, you should NOT see temp going from 210 to 170F, but rather it should be in the 190 - 200F range, when cruising, and radiator fan should NOT come on.

It sounds like your coolant pump is NOT operating (at least at high enough speed) until the fan kicks in (for some reason). You don't post your model or year (necessary for correct circuit diagram information), but just guessing from some prior posts, you have a 335i E90, and if it is 2008 or later, then the following schematic applies (drill down and get correct diagram if 2007 or earlier):
https://www.newtis.info/tisv2/a/en/e...ooling/vRilOSj

Start with checking fuse F37 (30A) which powers the control for both the Coolant Pump and Thermostat, and if you can monitor fan speed, pump speed, ECTS temp signal and Radiator outlet temp signal while cruising at steady 50 - 65 MPH, as you can with INPA, then you can probably get a better idea of what is happening.

INPA allows you to MONITOR in "Activations"/ Steuern (F6) BOTH (1) Thermostat opening position, and (2) Coolant Pump speed (as percentages of max), along with ECTS Temp Signal and Radiator Outlet Temp Signal, so that you can see what is going on with the pump and thermostat. That would be the best diagnostic for your wild coolant temp fluctuation (between 210F & 170F). As stated before, if the fan is coming on while cruising, I don't think the FAN is the issue.

George

I was able to get INPA running on my work laptop today, it was quite easy actually.

Tested all cooling items (fan, water pump, and t stat) and all seem to be functioning fine using INPA. The fan will run for maybe 10-15 seconds when I activate in INPA then shut off, not sure if that's normal or not. Here is a video showing it...

I tried my best to get it to go into limp mode while monitoring using INPA but was unsuccessful, obviously it wouldn't fail when I actually want it to . It went into limp mode both to and from work today, hopefully tomorrow it will and I can open INPA when it does.

When driving around the fan is usually at 7%, going up to 21% when stopped. The water pump was around 65% when driving. Again, not sure if this is normal or not. The oil temp was all the way to 245*F and the water was a bit over 212*F when monitoring.

[Antetokounmpo]

Car finally went into limp mode after not going into limp mode for a few days. Here is what INPA was showing while fan was running full bore.

[Antetokounmpo]

Replaced the fan today, was super easy only took about 25 minutes and problem seemed to be resolved.

[PichaDis11]

[Ilma]

Originally Posted by Antetokounmpo

Replaced the fan today, was super easy only took about 25 minutes and problem seemed to be resolved.

I have had the same problem for about a month now.

Has your fan remained stable since you replaced it - no codes and full speed fan leading to limp mode?

[Antetokounmpo]

Originally Posted by Ilma

I have had the same problem for about a month now.

Has your fan remained stable since you replaced it - no codes and full speed fan leading to limp mode?

It's been perfect since replacing

[CCiCarbon335i]

Hmm seems like I might have the same issue, my fan wasnt even coming on tho. Have cables ordered and going to install INPA today.
My tstat housing blew the seal though resulting in having to disassemble everything.
Ordered a new temp sensor, used fan and tstat.
Hope this gets it going.

[studio54]

Got the exact same problem yesterday after a hard drive.

Car went into a limp mode without light. Hooked MHD to read codes and got 2EFF.

When i was at idle reading the code, i heard something was grinding, maybe something touched/blocked the fans??
And a minutes or two later, suddenly the orange light of high heat popped on the dash. (The red did not popped).

I stopped engine, cleared the code, restarted the engine, fans blowed a few seconds probably to cool down previous heat and problem was gone, no code and power restored.

What to check ?

I will hook INPA tonight to make the E-BLOWER test and probably i will remove the fan to inspect and also inspect wiring.

I was shocked to read that a fan is 600$ !

[928]

Resurrecting this thread. I'm having exactly the same symptoms as the OP. I replaced the waterpump and thermostat but the fan still comes on with the 2EFF code. Antetokounmpo, did you replace the entire fan assembly (OE BMW part) or just the fan? I see on FCP Euro's site that they have both options...

[Antetokounmpo]

Originally Posted by 928

Resurrecting this thread. I'm having exactly the same symptoms as the OP. I replaced the waterpump and thermostat but the fan still comes on with the 2EFF code. Antetokounmpo, did you replace the entire fan assembly (OE BMW part) or just the fan? I see on FCP Euro's site that they have both options...

I replaced it with this one: https://www.rockauto.com/en/moreinfo...Btba8D7g%3D%3D

Been great since.

[928]

Thanks for posting, that's great to know and a terrific price! It looks like a lifetime warranty for the original purchaser as well. Unfortunately the fitment note indicates it won't work on my 2010 335i xdrive

[928]

Actually, the Rock Auto page is a bit confusing, but going to TYC's page indicates it will fit. Thanks again for your reply!

[928]

Not knowing for sure if the source of the problem was the fan, and given a list price for the OE fan of $2200 (CAD) plus taxes, I ordered the TYC from RockAuto. I've taken two longish drives since the replacement and, so far, no 2EFF code. Thanks to Antetokounmpo for the info on this replacement fan. Hopefully I'll have the same experience as you re longevity. For any future readers that find themselves in the same situation, I've attached a couple of pics of the two side-by-side. The fitment of the TYC is perfect. The only thing you have to do is transfer over the rubber plug that secures the fan to the hose on the right side and the two little clips on the top right and left side for the coolant reservoir overflow line. My car has the oil cooler that screws into the bottom side, so it was necessary to have the car in the air to do the replacement.

[Antetokounmpo]

Happy the help, going on 3 years strong with mine. It still baffles me the cost of the OEM one.