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AC & Service Engine light

13K views 26 replies 6 participants last post by  wheeler000 
#1 ·
Hello forum,

I have a 2001 325i, auto w/ 112k miles.


Just a quick note that may not mean anything but it seems my cooling fan is a little loud, not rattling or anything, I just hear it more than the engine when the car is running and I am walking around it. The Carfax showed that the car was serviced for cooling after the fan recall (and regularly maintained thereafter) so I don't think the one-owner would have let that slide for ~10 yrs... but I figured I'd mention it just in case it's a problem...

AC:

Blows ice-cold 99% of the time during my first 1 hour drive but twice got warm for about a minute each time. WTH? :dunno:


Service Engine Light:

Bought the car from a dealer that got it as a trade. Light was on then but I asked them to make sure it was off b4 delivery. They delivered it to me today (2hr drive from dealer) and the light was off... they had said the thermostat hose and a small vacuum leak were the culprits... and when I had test drove the car there was the slightest hesitation from a complete stop... when the car was delivered the light was off and the hesitation was (and still is) gone. However, the light is back on and I was wondering what the most common issues/ suggestions are for a 100k+ mi BMW.

I suppose I will get the code checked out tomorrow at Advanced Auto Parts (but they are usually pretty useless and tend to just look at my... well it ain't my eyes...)

Thoughts? Ideas?

Thx!!!:thumbup:
 
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#2 ·
Put on a loose sweatshirt, dress down and go get the codes read. Without that info it's really just a guess as to what could be wrong. Then post the specific codes here and those with knowledge will help.

In the meantime, read the E46 wiki at the top of the page. There's lots of info in there pertaining to all different aspects of your car.
 
#3 ·
My last blog entry (link in sig) dealt with A/C issues and what to look for, might be worth a read. I also did a video recently on how to check pressures and general once over stuff. Get us the CEL and let us know. Whatever you do, don't listen to the Autozone guy when they try and tell you what the code means.
 
#4 · (Edited)
Code Read and other adventures

Hello again,

So, yesterday was interesting.

AC:
Same story as above. No change.

Service Engine Light:
Had code read at Advance Auto. The only thing that came up was PO155 Bank 2, Sensor 1. I hung out at a friend's house for 3 hours later in the day and when I got back in my car the light was off. I am wondering if my "#1" below isn't the issue...

However,... four things...

1. My temperature readout (under the odometer) is reading -40 degrees... and twice in beeped and blinked at me.

2. There seems to be a low volume hum that happens every now and again that seems to come from the rear of the car. It sounds like a wannabe thug is pumping bass as his car drives by... but it has happened with no other cars around. Again, it is difficult to hear and near impossible if the radio is on.

3. Got cut off in a parking lot (seriously) and had to brake hard (worked great) but I smelled oil after that for a little bit and then it went away...

4. I added some windshield washer fluid as per the dash light. About 30 minutes later there was a puff of smoke from the passenger side engine compartment which stalled me when I pulled away from a stop sign. Soon after the washer light came back on... I haven't looked yet but I think the container is broke and that's what caused the puff and light as the car ran ok afterward.

In a nutshell... Help...:eek:
 

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#9 ·
Hello again,

So, yesterday was interesting.

AC:
Same story as above. No change.

Service Engine Light:
Had code read at Advance Auto. The only thing that came up was PO155 Bank 2, Sensor 1. I hung out at a friend's house for 3 hours later in the day and when I got back in my car the light was off. I am wondering if my "#1" below isn't the issue...

However,... four things...

1. My temperature readout (under the odometer) is reading -40 degrees... and twice in beeped and blinked at me.

2. There seems to be a low volume hum that happens every now and again that seems to come from the rear of the car. It sounds like a wannabe thug is pumping bass as his car drives by... but it has happened with no other cars around. Again, it is difficult to hear and near impossible if the radio is on.

3. Got cut off in a parking lot (seriously) and had to brake hard (worked great) but I smelled oil after that for a little bit and then it went away...

4. I added some windshield washer fluid as per the dash light. About 30 minutes later there was a puff of smoke from the passenger side engine compartment which stalled me when I pulled away from a stop sign. Soon after the washer light came back on... I haven't looked yet but I think the container is broke and that's what caused the puff and light as the car ran ok afterward.

In a nutshell... Help...:eek:
Replace the ambient temp sensor and you intermittent AC issue will go away
 
#6 ·
The code is for your oxygen sensor. You have four of them, two that are easily accessible but not your problem, and the other two are tough to get under the car, the one that is bad.

For the temperature reading, it is probably the outside temp sensor which is located under the front bumper on the drivers side (a cone type plastic part sticking out in the wheel lining)

Your tank or one of the pumps might be leaking on the tank, have it checked out. Be sure to look for any oil as well around the engine and look on the ground once in a while as well. It would be good to meet with a member that is in your area for additional help.
 
#7 ·
This morning -

Stalled once when the car was cold and I was accelerating off a stop sign. Later, I got the puff of smoke in the same spot (front passenger wheel well area)... I was pulling into a parking spot and I'm wondering if when I was braking the shock compressed and released the smoke??? They (washer fluid/ puff of smoke/ stall) seem to be separate issues that just happened to coincide the other day. What do you think?
 
#10 ·
A leaking valve cover gasket is one common cause for smoke from the passenger side. Look for oil on the manifold near the back of the motor on the passenger side. Also, check under the car for oil spots after it's been parked for a while(at least overnight).

Leaking windshield washer pumps are also common, will cause you to lose washer fluid pretty fast, but are cheap and easy to replace. If your engine bay is mostly clean, you should see dried washer fluid (a blue stain) near the reservoir.
 
#11 · (Edited by Moderator)
Update

Sensors are ordered.

The top part of the stem of the washer fluid pump has been tightly wrapped in teflon tape to stop the leak... unless I can find the new rubber washer.

CCV assembly is ordered.

There is some oil on the passenger side of the engine compartment near the firewall. I don't know if I want to replace the valve cover gasket or have it done. BUT I am afraid that the amount of oil present is not enough to account for the puffs of smoke.

Stalled once at the end of the block this morning.

Heard dull hum twice again.

I changed the oil & filter and although the filter didn't look too bad the oil was black... I cannot believe the dealership actually changed it like they said... and even if they did... I doubt they used synthetic.

When I started this morning I had a good amt of dull-white smoke out of the tail-pipe for a few moments... it was super humid/ rainy all day yesterday... possible condensation?:dunno:
 
#13 ·
Sensors are ordered.

The top part of the stem of the washer fluid pump has been tightly wrapped in teflon tape to stop the leak... unless I can find the new rubber washer.

CCV assembly is ordered.

There is some oil on the passenger side of the engine compartment near the firewall. I don't know if I want to replace the valve cover gasket or have it done. BUT I am afraid that the amount of oil present is not enough to account for the puffs of smoke.

Stalled once at the end of the block this morning.

Heard dull hum twice again.

I changed the oil & filter and although the filter didn't look too bad the oil was black... I cannot believe the dealership actually changed it like they said... and even if they did... I doubt they used synthetic.

When I started this morning I had a good amt of dull-white smoke out of the tail-pipe for a few moments... it was super humid/ rainy all day yesterday... possible condensation?:dunno:
This is a classic sign of a leaking valve cover gasket. The puffs of smoke happen because the oil is being burned off on the outside of the manifold. If you're going to DIY the CVV, you might as well take on the valve cover gasket too. It's much easier.

And I'm not insisting your VCG is leaking, but you do have some classic symptoms. Keep an eye on it.
 
#12 ·
as Smolk says, replacing the amb temp sensor will restore A/C. When the sensor goes iffy, as a precaution to prevent damage, the computer shuts out the compressor b/c it thinks its too cold for it to run.

I recently had to have my radiator replaced in my 00 after a small fender bender and the old one had a good amount of crud covering it... beforehand the fan was pretty loud and sometimes howling when driving; in a long about way I'm just trying to say that you may have alot of crud between the radiator and condenser causing inefficient cooling and possible noise as air is not flowing right ... ever since my new radiator alls been silent as a nap.

White cloud from the tailpipe can be a sign of burning coolant... especially if the exhaust smells a bit sweet. Blueish smoke is a sign of burning oil.

Here is a tip which someone once told me about "diagnosing' the ccv -

One common failure item you didn't mention is the crankcase vent valve and 4 associate hoses. Here is some info on this.
The crankcase vent valve and 4 associate hoses fail and cause a vacuum leak. The valve gets stuck open and the hoses crack. These last 70-120k miles and usually fail 80-90k miles. Here are a couple diagnoses.
At warm idle, place a small plastic freezer storage bag on its side over the oil fill hole. If the bag sits on top or gets slightly sucked in, ~1", the valve is good. If the bag gets significantly sucked in the hole the valve is stuck open and bad.
With the engine off and cold, carefully remove the hose at the valve cover front corner. Blow hard into the hose. You should hear oil bubbling in the oil pan. If you don't hear the bubbling the top or bottom hose is likely cracked. The bottom hose often breaks just below the valve connection. There can also be cracks in the other two hoses.
 
#15 ·
Spark plugs - Complete

VCG - Complete

O2 Sensor - Complete

Waiting on CCV to arrive.

Waiting on Temp Sensors to arrive (I have Auto-interior temp control).

Found out that both temperature sensors behind the front bumper have been ripped out... just two thin, dangling wires on each side of the car.
 
#16 ·
Found out that both temperature sensors behind the front bumper have been ripped out... just two thin, dangling wires on each side of the car.
IN the interim you can twist the two wires together, this will give you a constant reading of 122 degrees. Not accurate obviously, but it will make your A/C blow cold ALL the time. The wires on the passenger side are not for the ambient temp on the dash, it is for heated nozzle washers I believe.
 
#18 ·
That pic is correct. But I always like to real time scan my 02 sensors with a scanner that has that capability so as to make sure. But as easy as it is to replace, I would just do it and see what happens.
 
#19 ·
Work Complete but SES on

Replaced the hard hose (which was apparently cracked and "fixed" with electrical tape) that goes from the valve cover to what I believe was the ccv. The ccv is simply too big a job for me and I did not hear the Chewbacca at all.

When I was changing the vcg I found a lump of charred stuff behind the 3rd cylinder... cleaned it out...

Started car after all above was complete and did not get the white smoke from the tail-pipe; however, the car did still stall when I gave it gas in park... SES light was still on... I am wondering if the computer is still using the old info before all corrections were made?

If so, do I just head to Advance Auto and clear the code?
 
#21 ·
Reset codes. Everything run well w/o issues for an hour. However, when I was about the leave Advance Auto my operating temp gauge started to go through the roof. I shut down immediately in the parking lot. My radiator light had been flickering all day. The mechanics next door took a look... I thought it was the thermostat and figured it would be better to just get it down right then rather than tow home and do it myself. I had seen it bump to the 3/4 mark 2x before but nothing like this. Turns out the system just needed to be bled as it let out air. The dealership (Jeep) where the car was traded in did their little check-up on the car before I bought it and so far I found out that they only added ~5qts of oil, the breather hose from vcg to ccv was fixed with electrical tape, and they didn't bleed the radiator after topping it off...
 
#27 ·
2 questions or one question 1 comment. you're saying the p0155 was one of the pre cat sensors? And...I was told it was a get some sort of Federal Regulations for the auto parts store to clear your codes. is that not true?
 
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