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RSFS 11-14-2013 06:20 AM

2005 X-5: Cold start only- Temp gauge pegs hot
Can anyone help with this issue. My 2005 X5 4.4i will only start when the engine is cold. Once it warms up it is very difficult to start- if at all. (Only when depressing the accelerator to the floor) When I turn the ignition on the temp gauge reads the actual temp for 2 seconds and then goes to the full hot position.

I added some coolant and this seemed to have fixed the issue, for 1 day. Then back to the same symptoms. The fluid level is full.

The 2 P-Codes reading are P0300 "Random Misfire Detected" and P112B which I can not find the definition for.

Any help would be greatly appreciated!

james.e30 11-15-2013 12:59 PM

It looks like P112B is a Coolant Temperature Sensor code. That would explain your wonky temperature readings. Check the electrical connections to the sensor, if that doesn't do it you may have to replace the sensor.

Also, if your coolant was low you should bleed the system when you top off. There are directions in this post.

leejim 11-15-2013 06:38 PM

Hard starting etc.
Hi probably the cause of your starting problems also I would think ?

james.e30 11-16-2013 10:09 AM

Yes. The computer will manage a cold start differently than it would a hot start. Your timing (VANOS) is probably incorrect for the condition of the engine, which would explain the misfire code and the difficult starts.

RSFS 11-18-2013 03:32 PM

Took it to a BMW shop today and the codes do not point to the condition! It does give some Thermostat and temperature sensor indications, but nothing that points directly to the symptom. I have learned that I can get it started with some effort, but it starts when cold- without any issues and runs fine. (It was running great until the day this happened- just a random time when it just wouldn't start.)
Discussed this with the mechanic and he had not seen this. The odd indication is how the temp gauge, when the ignition is switched on but not started, will register normal for 2 seconds and then swing to full hot, even though the engine is not warm.

I am going to try replacing the thermostat and possibly the temp sensor as well as bleed the coolant.
Several other sources thought it might be the Crank shaft sensor, but no codes came up with this.
Frustrated.... to say the least!

Thanks for the suggestions- and please keep them coming- I need to get this thing running before the snow starts falling!

RSFS 12-11-2013 03:10 PM

Just an FYI to bring this issue to a close.

The main cockpit indication of this problem was the temperature gauge giving a normal reading for several seconds and then swinging to the full Hot position regardless of actual temp. It would start without problem when it was cold and had sat for some time. (i.e. over night) Once it had been run, it would not start again, or be very difficult to get started.

Computer did not read anything that would lead to the issue at hand.

I changed the Thermostat and temperature sensor and flushed the cooling system and it was still giving me a "hot reading". After taking it for a short test drive the Expansion tank blew. I had suspected this might be an ET issue. Once I replaced the ET, the problem was solved. While 3 parts were ultimately changed out, I believe that the ET was the cause of this failure. With a "hot" reading, it was shutting the engine down.

All three parts were quite easy to change.

Thank you all, for the input along the way.


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