[james008]

First - I just had my water pump and thermostat replaced maybe 2,000 miles ago.
Second - I flashed back to stock DME and am not running any flash or piggyback.

The problem- after about 15 miles of driving (highway or city) I get reduced power / poor pedal response and the radiator fan goes full speed.

Turn off the car and turn it back on, runs normal.
It threw a code once 12003 - coolant temp sensor plausibility Inpa showed 3 stored faults all the same freeze frame data had coolant temp right at 90 Celsius.

Today it did the same thing, but no CEL. Stopped for gas car ran fine, fan ran normal for the remainder of the drive (5 miles).

I ran the bleed process different times after driving, and fluid level is full.
I just changed oil within the last 1,000 miles and no coolant in oil.

I have not read anywhere that this code actually means a faulty coolant temp sensor, everything pointed to the Procede which I am NOT running.

For $15 I might just change the sensor to change the sensor. On my drive home I will monitor Coolant temps with obd2 and torque.

Thoughts?

[james008]

Update: drove home (34 miles) watched coolant temp on torque app, it fluctuated between 188 and 200 degree Fahrenheit and spiked a couple times to 203 and once to 206.

Radiator fan never went into high speed and throttle response seemed normal the entire drive.

I did notice the temp jump from 197 to 188 and then back up to 197 within just a couple of seconds which I thought was weird.

Oil temps seemed extremely low at 220 degrees and early in the drive was even lower.
Ambient temp here is 90 usually I see the oil temps in the 230-240 range. (I do have an ER oil cooler but stock oil thermostat).

[james008]

It did it to me again today. Quickly plugged in Torque and Coolant temp was reading 170 Fahrenheit. Fan blowing full blast, no throttle response. I turned the car off and immediately back on and car ran normal.

It threw the check engine light "coolant temp sensor plausability"

Anybody have any thoughts?

[CoffeeBean]

Sounds like the sensor. Also explains the weird jump in temp. Fan probably goes full on when the sensor is acting up just to be "safe".

[ferocity02]

Hmm... maybe you should change the coolant temp sensor?

[james008]

It would be the first time in the history of mankind to be the cheapest part and a 5 minute diy to fix a problem on a BMW! Never the less I changed the sensor, will wait 2 days before I jinx it.

Originally Posted by ferocity02

Hmm... maybe you should change the coolant temp sensor?

[james008]

Replaced sensor everything works as usual. There was a bit of a coating on the sensor, can't believe the sensor was the actual problem.

[Ilma]

Even though you have it turned off, is the Procede still installed in the wiring harness of the DME?

I ask because I had your symptoms exactly and it turned out to be a grounding issue with the downpipe fix wiring creating excessive voltage swings on the same circuit as the coolant temp sensor.....since they share the same ground wire apparently.

That is why the error message is showing as "implausible" - the voltage swings on the ground wire give the DME the impression that coolant temp changes are unreasonably large.

I usually only got the error while driving on the highway for 15 mins or so at a constant speed......city driving was fine.

If the symptoms reappear with your new sensor installed, then it points to the Procede and you should remove it entirely, or do a modification on the Procede wiring harness that disables the downpipe fix circuit.

[Vishnu]

So i'll be driving for awhile and then the fan turn on and goes into limp mode.. If i turn off the car and back on for a second it goes back to normal.. Is the same engine temperature sensor?

[Jaronbwall]

Originally Posted by Vishnu

So i'll be driving for awhile and then the fan turn on and goes into limp mode.. If i turn off the car and back on for a second it goes back to normal.. Is the same engine temperature sensor?

If you have not diagnosed the issue like the above thread you mostly have a bad water pump. Unfortunately, 90% of the time that's the issue depending on your mileage, model year, etc. The DIY replacement for the pump and thermostat isn't hard and you'll save thousands! If you have any questions I'm willing to answer them. I replaced mine last year.

[Antetokounmpo]

Originally Posted by Vishnu

So i'll be driving for awhile and then the fan turn on and goes into limp mode.. If i turn off the car and back on for a second it goes back to normal.. Is the same engine temperature sensor?

Originally Posted by Jaronbwall

If you have not diagnosed the issue like the above thread you mostly have a bad water pump. Unfortunately, 90% of the time that's the issue depending on your mileage, model year, etc. The DIY replacement for the pump and thermostat isn't hard and you'll save thousands! If you have any questions I'm willing to answer them. I replaced mine last year.

See my thread..

https://www.e90post.com/forums/showthread.php?t=1538266

Had the same problem but I had a hidden code for "fan self diagnosis" it sounds like he's got the exact same problem since he said limp mode, not overheating mode. I would get a code reader that can read hidden codes to see if you have 2EFF or any fan codes. Fan replacement was super easy (25min).

[Vishnu]

I had the same symptoms as you replaced that sensor but now is doing the same thing except the engine doesn't overheat just fan stays on for as long as the car is running.

[Antetokounmpo]

Originally Posted by Vishnu

I had the same symptoms as you replaced that sensor but now is doing the same thing except the engine doesn't overheat just fan stays on for as long as the car is running.

I replaced my coolant temp sensor as well just Incase since it was like $15, didn't fix the issue though. You need to read the codes.

[Vishnu]

they are coming up i ran function to bleed the lines and waterpums is working...
When ever the fans do click on it stop and restart the car and it runs fine..

[Antetokounmpo]

Originally Posted by Vishnu

they are coming up i ran function to bleed the lines and waterpums is working...
When ever the fans do click on it stop and restart the car and it runs fine..

Like I said, I had the exact same symptoms as you.

[Vishnu]

What did you do to fix it?

[Vishnu]

I have a p2aaf p23998 p2e82

[Antetokounmpo]

Originally Posted by Vishnu

I have a p2aaf p23998 p2e82

What type of 'limp' mode is it? Those are water pump codes.. you're sure it's not overheating?

[Vishnu]

When I turned the car off tonight I heard the water pump turn on...

Same thing while driving the fan would turn on.. I turn off the car for a sec and everthing goes back to normal..

[Vishnu]

When the fan goes on if i leave it on the car will go to over heat...

Right when i turn off the car and turn it back on everthing goes back to normal.

[Antetokounmpo]

Originally Posted by Vishnu

When the fan goes on if i leave it on the car will go to over heat...

Right when i turn off the car and turn it back on everthing goes back to normal.

Ok... would've been helpful if you said it was overheating before. Sounds like a typical waterpump failure.

[BMW-SRT]

I had the same issue during the summer, issue started after my old JB4 box melted and I replaced it with a new one, car drives fine never overheats, after driving for a while the fan just kicks on full speed (or if I get on it) no error codes or anything, I figured there was something wrong with the jb4 wiring harness, oddly now that its “winter” here in California it hasn’t done it in a couple months.
Now i hardly drive the car maybe once or twice every couple weeks, so I haven’t worried about troubleshooting the issue as my daily is my x5m but figured the person who said there might be a bad ground might be right to those with piggy-backs on their DME’s