09 LaCrosse CXL - More sudden issues - P0327, Low Oil Level & A/C not working

NittanyDoug

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I don't know what the heck happened this week but my car has a gremlin in it somewhere.

First in another thread I'm chasing down ABS/TC issues/lights.

After I started that thread I went out to go and I get a Low Oil Level warning in addition to the TC/ABS/Stability warnings and a CEL on plus the A/C in auto mode (or any mode) stopped working. I went to a parts store to get the codes read and he told me the TC/ABS/Stability is from my front passenger, ok no problem. The CEL was P0327 which is Knock Sensor #1. If I look at the service manual correctly it must be tapped into a cooling passages of the block because it tells you to drain the coolant first.
I am due for an oil change this weekend (still shows 45% left but I have almost 6,000 on it, Mobil 1 and I wasn't low on oil.) Guy said sometimes that sensor gets funny when you need an oil change.

Then and probably most frustrating is the A/C. He said there was a code in the reader about the A/C not working. I didn't pay any attention because it had come back on when I drove to the parts store. I thought it was a fluke thing until last night driving home. Next week is supposed to get hot again and I need A/C (have a toddler.)

I put a gauge on the A/C but I couldn't get the compressor to kick on so it wouldn't give me an accurate pressure reading.

Any help on any of these? I tried searching and not much out there.
 

douger

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The HVAC control module gets voltage through 2 fuses. One is a 10 amp "HVAC" fuse on the instrument panel fuse panel, which is hot all the time, and a 10 amp "display" fuse, number 16 on the underhood fuse panel, which is switched.

There's an oil level sensor, p/n 12603782 located in the middle of the front side of the oil pan. I don't sell many of them, but I have sold a few. That sensor has nothing to do with oil life, which is basically an algorithm based on mileage, speed and other inputs. I'm making the assumption you have the V-6 engine.

Yes the knock sensor is in a coolant passage. There's a note in SI not to put any more sealant on the threads than what comes on the part already. The #1 sensor is at the front of the engine.
 

NittanyDoug

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Thanks Douger. I'm going to try to pick up the knock sensor as well. I doubt on such short notice that I can find the oil level sensor replacement. I'll check the fuses on the HVAC. I just don't understand how these issues pop up at once like this.
 

douger

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Re: 09 LaCrosse CXL - More sudden issues - P0327, Low Oil Level & A/C not working

One seemingly common failure point in all of your issues is the BCM. I'd check the grounds, two of which run off the negative battery cable. The three other ground points are behind the left knee bolster, near the steering column, one is bolted to the instrument panel carrier, to the left of the glove box, and one is at the left sill, forward of the seat. All but one have black wires, with one being black with a white tracer. Remove the bolts, make sure all terminals are clean and firmly attached to their wires, and that the body attachment points are free of corrosion.

- - - Updated - - -

Thanks Douger. I'm going to try to pick up the knock sensor as well. I doubt on such short notice that I can find the oil level sensor replacement. I'll check the fuses on the HVAC. I just don't understand how these issues pop up at once like this.

I wouldn't sweat the oil level sensor until you're ready to change the oil.
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NittanyDoug

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Re: 09 LaCrosse CXL - More sudden issues - P0327, Low Oil Level & A/C not working

Oil will be changed sunday regardless of getting a replacement sensor. I know it has oil in it. It seems to come and go. Sometimes it shows up and not other. And it doesn't throw any kind of code along with it.

I'll look into the grounds. It would seem to be something where I got water in or something like that. A squirrel decided to chew wires, who knows. I'm not totally surprised by the wheel speed sensor as it has been intermittent for months.
 

NittanyDoug

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The HVAC control module gets voltage through 2 fuses. One is a 10 amp "HVAC" fuse on the instrument panel fuse panel, which is hot all the time, and a 10 amp "display" fuse, number 16 on the underhood fuse panel, which is switched.
.

I checked Both of those 10A fuses. They both look good and test good on a MM.

You have to give me some hints as to where to start looking for the BCM though....never dug that far into things. Motors, gears, sure, but not so much on this electrical controls stuff.
 

douger

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I checked Both of those 10A fuses. They both look good and test good on a MM.

You have to give me some hints as to where to start looking for the BCM though....never dug that far into things. Motors, gears, sure, but not so much on this electrical controls stuff.

On the left side of the instrument panel, there should be a piece of removable trim that makes up the end of the panel. It clips in, so gently pry it off. The BCM is hiding behind that panel.

The best you can do as a DIYer with a BCM is to unplug both connectors and plug them back in to reseat them. BCM replacement involves programming. I'm not saying your BCM is at fault, rather it seems to be a common point of failure for all of your issues. Checking the grounds won't cost you anything but your time.
 

NittanyDoug

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Everything is a possibility at this point. I also have the info at home on what things should ohm out to. Ugh I hate this.
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NittanyDoug

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Wel like in my other thread...I found the problem. A squirrel, rat, chipmunk or other nefarious rodent chewed through 7 wires in that harness. It wasn't a terrible fix, just time consuming after I found the cut wires. I have a feeling he sat on that aluminum cross member and happily chewed his way into my misery. I cleaned it all up, soldered and shrink tubed all connections. I also added a couple of inches just to make it easier for soldering when it was just on ramps. I added more wire covering too. As soon as I done I cleared the codes and fired it up. Everything was perfect. I cycled things a few times and checked pending codes and nothing. It's all clear! All told it was the wheel speed sensor wires, a/c compressor clutch wires, knock sensor wire and oil level wires.
 
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