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Last night I was driving and all of a sudden the car stalled on me. I was not able to get it going again and had to push it home. After I got home I tried but it wouldn't start again. The car does crank over like it wants to start and intermittently it gets a little bump of power like it almost starts, but always fails too. I tried starting it this morning. It started and ran for 2 minute's but died again. I ran a Diagnostic code scanner and I have this. Is it possible I have a bad ecm considering how many sensors failed here. Or any clue what could have happened or the cause for this.

68429
 

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If a check engine light or message was not already present before this happened the first thing I would check is battery terminals for corrosion or loose connection and relays, fuses, ground cables. when you open fuse box check for a burnt plastic smell but sometimes relays go bad with no sign or smell, shine fuses with flashlight from side to look for any obvious blown fuses/resistors look for PCM or ECM relays/fuses I've seen a bunch of random codes and intermittent starts and cutoffs on other cars caused by PCM relay not specifically on yours. Also I noticed oil pressure switch codes make sure there's no new oil leaks under or on side of motor locate oil pressure switch and if possible unplug it and check for oil coming out of connector they usually have a diaphragm inside if it starts to leak through connector it can short out and cause all kinds of problems and just having a slight drop in oil pressure alone will cause issues especially with VVT motors. I don't know the specifics on your vehicle or motor but I was looking at this site for info on a Malibu and thought I would give some universal info from my experiences with other vehicles with similar problems Good luck!
 

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Check harness to these components for short/damage. Then I would check 5v reference voltage to each component as one may be shorting out the 5v voltage. This is upper level diagnosis. One of the sensors or harness may be causing all the codes as they use the same 5v reference. Try unplugging one at a time and testing. P0641 is for the 5v circuit and is shown several times in your scan. Good luck.

Diagnostic Aids

The 5V reference 1 circuit provides 5 V to the sensors listed below:

- Air conditioning (A/C) refrigerant pressure sensor

- Exhaust and intake camshaft position sensors

- Engine oil pressure sensor - cylinder head

- Engine oil pressure sensor - engine block

- Fuel pressure sensor

- Fuel rail pressure sensor

- Fuel tank pressure sensor

- Multifunction intake air sensor
 

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Discussion Starter #4
Check harness to these components for short/damage. Then I would check 5v reference voltage to each component as one may be shorting out the 5v voltage. This is upper level diagnosis. One of the sensors or harness may be causing all the codes as they use the same 5v reference. Try unplugging one at a time and testing. P0641 is for the 5v circuit and is shown several times in your scan. Good luck.

Diagnostic Aids

The 5V reference 1 circuit provides 5 V to the sensors listed below:

- Air conditioning (A/C) refrigerant pressure sensor

- Exhaust and intake camshaft position sensors

- Engine oil pressure sensor - cylinder head

- Engine oil pressure sensor - engine block

- Fuel pressure sensor

- Fuel rail pressure sensor

- Fuel tank pressure sensor

- Multifunction intake air sensor
I actually figured out the problem last night when diagnosing I did check all the wire harnesses but that 5v code really threw me off so I decided to inspect the ecm itself. When I pulled the top gray plug for it oil/water substance came out of the plug and after further inspection 3 pins were corroded and this substance somehow go into the ecm aswell. I cleaned the pins on both the ecm and the plug, and all the codes went away and it starts perfectly ok now but I couldn't open the ecm and because there was this liquid in the plug I have no doubt it is in the ecm aswell. After further inspection, the O-ring on the plug appeared to be brittle and broke off easily and wasn't making a seal. I ordered a new O-ring for the plug as well as a new ECM because as I said before I have no doubt in my mind that there is that liquid inside of it as more came out when I tipped it. Better to be safe then sorry.
 

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I use Deoxit on all my electronic connectors as getting into the plugs is impossible. I coat around the outside of the plugs with dielectric silicone to seal them, not on the pins as once it's in there it's impossible to clean them if needed.
Glad to see you solved your problem, unusual issue.
 

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@Powerup0 thanks for posting your resolution! It really helps out the forum when people share their information. It's great you got the car fixed pretty inexpensively.
 

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Discussion Starter #7
I use Deoxit on all my electronic connectors as getting into the plugs is impossible. I coat around the outside of the plugs with dielectric silicone to seal them, not on the pins as once it's in there it's impossible to clean them if needed.
Glad to see you solved your problem, unusual issue.
This is a good idea this is what I will do. The codes came back briefly yesterday when I was test driving it to see if they would and they did after an hour of driving the service stabilitrack and reduced engine power came.on after a hard acceleration. I still 100% believe it's the ecm after finding a pin out and seeing which corroded pins belong to which sensor. However if this doesn't resolve my issue I'm going to manually check every sensor myself. I will keep you all updated. And when I get a new ECM I will use dielectric grease to seal the plugs that's a good idea.
 
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