2003 Mazda 6 Wont start in cold weather
 

I have 2003 Mazda 6, when the weather is below 40-42 out side the car will not start. When i turn the key I just get a click and the car doesn't try to turn over. If its warmer outside the car starts and operates fine. I have tested it for codes and received three different ones p2107, p2110, and p2100.

After receiving the codes i have taken the following steps, I put a fuel additive that is supposed to remove moisture, tried heating fuse relays, and using cold start spray. Sometimes the cold start spray would start the car and once it was running it normally stayed that way.

I took the car to the Mazda dealer and they ran a diagnostics check on it, told me the throttle body needed to be replaced. So i picked up the car and replaced the throttle body myself, same issue still exists.

I started heating different sections of the car Fuse relays under hood, throttle body, fuse relays under the dash, and the PCM. It seems like after heating the pcm the car starts. So i figured i need to look into replacing it, but when i run the part number it comes up as an ecm, i thought they were different.

I have not had much luck finding a replacement and i have read that you need to get the exact match for your cars options.

Any help would be much appreciated.



Steve

PCM/ECU/ECM all the same thing, just different names.

I'm guessing you have a V6?

P2107 : Internal problems with PCM - Requires replacing

P2110 : NOT in my market

P2100 : NOT in my market

Read this, 2003 Mazda 6 codes P2100, P2107, P2110 - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum

Also, something I read, Non-genuine spark plugs may corrupt the
electrical signals in the throttle body actuator
circuit and cause electrical noise to be input
to the PCM. Also Dodgy Ignition coils can cause corruption too!!

Thanks for the reply, I had taken the car to the dealership to have them replace the plugs, and we did have a bad coil at the beginning of the last year. Do you know a good place to look for a new ecm? I wasnt having much luck looking online.

I Have a 2003 Mazda 6. Every year when temps get below 40 degrees car wont start. 50 degrees starts fine no problem. Runs fine. It is the TEMPERATURE SENSOR. Was reading I think -40 degrees outside so that is the problem with mine. Hope this helps.

Hi make sure your all ground wires body to the engine and v.s. have no corrosion have good connection .when warranty expired on my vehicle I never go to the dealer for repairs just for parts I tell you why.they just charge you big time what other mechanics charge you half the price or less.