The code I was getting was the P0128, I replaced the thermostat (Autozone) , the rubber seal around the T-stat was torn, after I replace, the problem went away for about a month. Well now it is back again and the code I get now is P0118, and P0116

 

Did you buy the temp sensor from Autozone also? You fixed it with the t-stat last time but due to where it came from it most likely went bad again or is the wrong temp. You must use an OE t-stat for a long term repair. I would never buy any electrical component from a chain store. Engine control sensors I always recommend Dealer parts. I have seen many aftermarket electronic sensors that were just not quite right.. Chain style parts stores are good for brake parts, fluids, filters, light bulb etc.... Anything else should come from a real auto parts Napa, Rock Auto, Fisher, Olympic etc.... Or the Dealer. Either reinstall your original temp sensor or buy one from the dealer. On Impala, Malibu, 4.2 liter Trailblazer and Envoy po128 is a common code. For the 4.2 liter engine we use aftermarket t-stats no problem but for some reason the Impala and Malibu you get a 50/50 shot with aftermarket so I only use a dealer stat in them now.

I see the same problems with different makes over and over. Its to the point when a certain make comes in with the check engine light on I know which choice of 2-3 codes are likely to be in them. The repair is always the same
Here is something else for you only partially relevant on a Toyota po128 is always a bad oxygen sensor. Not relevant to the coolant system per say but the O2 is what they use to measure.

 

MDTAHOE..Thank you so much for your replies, I guess I really didn't think different brand names and/or models would make a difference but apparently it does. So let me start by saying this. My car is not a Malibu. It is a 2007 Saturn ION 3, yes I know, slap me for posting in the wrong forum. Saturns are GM, so, looking to see what the fix is for GM cars. The T-stat I bought from Autozone is a duralast part # 4698, the sensor I bought from Autozone as well which is also a Duralast part number SU112. Would that be different than what the dealer would order? Thanks

 

There is a quality difference. You must use dealer parts for this.

 

I've had this problem for months. I replaced the temp sensor, no fix. I saw where a person said it was the thermostat. I didn't think it was possible but I was WRONG!
It is the thermostat. Malibu's with high mileage the thermostat will start leaking. Mine had the rubber internal gasket broken. This keeps the car from coming to normal temp in the correct amount of time the ECM is expecting. When this happens the ECM goes in a free run condition and turns off the temp gauge and the AC will not come on when the temp gauge is off. Get a good quality thermostat and replace it yourself (bottom left front of engine above the AC compressor. 2-10mm bolts, no gasket. Be sure new thermostat fits in the housing smoothly, especially the rubber gasket.

 

I am an owner of a 2011 chevy malibu LT. I don't know if this is normal or not, but my temperature gauge is a hair above the line below 1/2. it stays there and doesn't go up or down. my a/c gets cold and my heater gets hot. I thought it usually ran at 1/2, but maybe I just never noticed that this is where it was at. Is this a problem? temperature yesterday was about 80 if it has to do with that.

 

Hi 11malibuowner,

I understand that you are experiencing some concerns with your Malibu. I cannot guarantee anything, but I will be happy to take a further look into your concern. Please feel free to send us a private message in reference to this thread if any further assistance is needed. I look forward to hearing from you soon!

Kristen A.
Chevrolet Customer Care

 

the car is designed to run approx. between 80 to 100*C. If its in that range, everything is ok. Will a scan tool you can see the actual ect sensor reading.

 

My thermostat pin goes all the way up close by the H when I'm driving my car and the fan kicks on its not running hot or nothing. When I turn off the car the fan stays on for a while and turns off can anyone tell me what's going on with this situation. Appreciate it.

 

I had the same problems with my 2007 Chevy Malibu. Temp gauge was stuck on cold and air conditioning not blowing cold air. Drove it the day before and everything worked fine. So after stopping at a mechanics garage, they said it was a sensor in the control panel to bring it in the next morning and they would replace the sensor, at an approx. cost of 350.00. When I got home, I pondered over paying 350 for a sensor, so I let the car cool down, checked the coolant to make sure it was ok and not low. Everything good there, decided to remove battery cables to check the fuses. As a woman, I did not want to take any chances of getting shocked,,lol. I removed each fuse one at a time, replaced them. After approx. 15 minutes of checking fluids, no corrosion on battery cables, fuses all ok, and knowing the compressor worked from driving it that day and switching the a/c flow from face to floor to defrost, etc. I gave up and put the battery cables back on, and wandered what else it could be, as I know the a/c and temp gauge do not work together. So, I started my car back up, gave it a minute to see if the temp gauge would move or a/c would start cooling, and to my surprise, everything started working great. This was approximately 9 weeks ago, everything still works great on it. I talked with a mechanic who lives near me after I did all of this, and he said what I did was reset the control panel from unhooking the battery cables for approx. 15 minutes. Saved me 350.00 from a local rip off mechanic. I am a woman, and dollar signs light up when a woman walks into a mechanics shop. I know this for a fact. But, with 160,000 miles plus on her and me, we are both running fine.