09 Malibu intermittant AC issue
August 1st, 2012, 12:54 PM
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09 Malibu intermittant AC issue
09 Malibu intermittant AC issue
<HR style="BACKGROUND-COLOR: #ffffff; COLOR: #ffffff" SIZE=1><!-- / icon and title --><!-- message -->Hello all and let me say thanks in advance for any help I may gain here. After reading some of the posts, looks like there are some pretty smart people here to assist. So with the @$$ kissing done let’s begin.
Let me preface by saying, I'm no stranger under the hood of a car. I wrenched professionally for 10+ years until a back injury took me out. So I'm familiar with many troubleshooting flow charts and ideas. This is my girlfriends car, she purchased it new and its under 60K on the clock.
The patient: 2009 Malibu with the ECO tech 4 cyl.
The issue: Intermittent AC function, not blowing cold. This occurred AFTER a coolant temp sensor replacement and SES light came on. Light cleared, temp sensor replaced. The dash temp guage stopped working, or would act flakey.
The symptoms: The hotter the day, the less likely to blow cold.
What have I done: Checked AC charge and pressure, its smack dab in the middle of the gauge in the green charge zone, of your over the counter ac charge kits. I attempted to add charge, which caused it to be over charged, and had to release some Freon. The gage fluctuates on the low side like it should when the system cycles.
I have checked fuses, all good, relays, and all good. AC compressor cycles when its working, and when it works, you can make freezie pops in the vents.
What happens exactly? If it’s a hot day out, car sits in the sun or for more than a day, the AC will not always blow cold. It will intermittently work; cold, warm, cold, warm. This occurs driving, or stopping. So it’s not like it’s a low charge, because when it works, like I said above, you’ll get nipple hard-ons from it being so cold! All the while it works; it doesn’t lose its cool when stopped, so again, I feel this is NOT a charge issue. She can also just leave it on, and it will eventually begin working. Some days, it will work from the start of the day and not quit for a couple of days. Then it will not work at first, give its little hissy fit of cold and hot, then start working ok, and then the days...well forget about it, it will not work! We can play with the controls, sometimes that makes it begin working, or like I said, just wait it out and it will begin working.
My conclusion: I feel it’s the body computer. I’m not comfortable ripping it apart without a little guidance, and I know there has to be some way to reset it back to defaults and force it to relearn. But not knowing the correct procedure I’m hesitant to try some things. I have tried searching for them to no avail.
From another forum, it was suggested that the sun sensor was the issue.
The symptoms appear that you still have a sun load sensor issue for the compressor to cycle on/off/on/off that way. You mention that once the compressor kicks over it stays on and it only cycles the way it does on days that are hot. The way I see it there are 3 possibles 1) There has to be a bad ground from the sun load sensor to the PCM, 2) Sensor is defective.
So all of you good wise people, can you assist me with this? Or must we be at the mercy of the mighty Mr. Goodwrench service department?
Thanks!
Warren
<HR style="BACKGROUND-COLOR: #ffffff; COLOR: #ffffff" SIZE=1><!-- / icon and title --><!-- message -->Hello all and let me say thanks in advance for any help I may gain here. After reading some of the posts, looks like there are some pretty smart people here to assist. So with the @$$ kissing done let’s begin.
Let me preface by saying, I'm no stranger under the hood of a car. I wrenched professionally for 10+ years until a back injury took me out. So I'm familiar with many troubleshooting flow charts and ideas. This is my girlfriends car, she purchased it new and its under 60K on the clock.
The patient: 2009 Malibu with the ECO tech 4 cyl.
The issue: Intermittent AC function, not blowing cold. This occurred AFTER a coolant temp sensor replacement and SES light came on. Light cleared, temp sensor replaced. The dash temp guage stopped working, or would act flakey.
The symptoms: The hotter the day, the less likely to blow cold.
What have I done: Checked AC charge and pressure, its smack dab in the middle of the gauge in the green charge zone, of your over the counter ac charge kits. I attempted to add charge, which caused it to be over charged, and had to release some Freon. The gage fluctuates on the low side like it should when the system cycles.
I have checked fuses, all good, relays, and all good. AC compressor cycles when its working, and when it works, you can make freezie pops in the vents.
What happens exactly? If it’s a hot day out, car sits in the sun or for more than a day, the AC will not always blow cold. It will intermittently work; cold, warm, cold, warm. This occurs driving, or stopping. So it’s not like it’s a low charge, because when it works, like I said above, you’ll get nipple hard-ons from it being so cold! All the while it works; it doesn’t lose its cool when stopped, so again, I feel this is NOT a charge issue. She can also just leave it on, and it will eventually begin working. Some days, it will work from the start of the day and not quit for a couple of days. Then it will not work at first, give its little hissy fit of cold and hot, then start working ok, and then the days...well forget about it, it will not work! We can play with the controls, sometimes that makes it begin working, or like I said, just wait it out and it will begin working.
My conclusion: I feel it’s the body computer. I’m not comfortable ripping it apart without a little guidance, and I know there has to be some way to reset it back to defaults and force it to relearn. But not knowing the correct procedure I’m hesitant to try some things. I have tried searching for them to no avail.
From another forum, it was suggested that the sun sensor was the issue.
The symptoms appear that you still have a sun load sensor issue for the compressor to cycle on/off/on/off that way. You mention that once the compressor kicks over it stays on and it only cycles the way it does on days that are hot. The way I see it there are 3 possibles 1) There has to be a bad ground from the sun load sensor to the PCM, 2) Sensor is defective.
So all of you good wise people, can you assist me with this? Or must we be at the mercy of the mighty Mr. Goodwrench service department?
Thanks!
Warren
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