Ok guys I drive a 2005 G35 Coupe roughly 90k miles on her in Alberta, Canada. Yes it's cold however I no longer think this has anything to do with my issues.

I love this car but recently it's been a pain in the a**. Starting the car is nothing but stress. Sometimes I'll turn the key and it will turn over but not start. Changed the spark plugs but did not fix the issue. Then I thought it had something to do with the key as I has been using a copy rather than the programmed one. I noticed a weird occurrence where it turns over and does not start with the copy but it does start with the programmed key. For a while there everything was fine until it began getting cold. Went out one day to turn her on and it did not even click. Plugged her in for about 10 mins. and started right up and blamed winter for it. However if left sitting for too long it will not start even when it's not very cold out. Now these are pretty well known symptoms of a drain but it quickly became obvious that it was something else.

I had set an appointment at the dealer for them to examine my car due to these issues. Took her in and got her back with them saying everything is fine and that no problems were found so that's what I thought. Drove her to work, plugged it in and did not think much of it.

When I got off I noticed my lights were on (headlights, tailights). Checked to see if I accidentally left them on but nope. Weird thing is I could control all of my light features, including brake lights and even the effing power windows, with the car completely off - not even the key in the ignition. Tried starting it. Did not start. Unplugged block heater and plugged it back in. Started rough after about ten minutes.

Drove it home and there she rest for all of eternity because the same thing happened except this time it does not even crank and I have many dash lights on including the traction control and seatbelt. There is a constant whirring noise coming from the engine bay and the A/C light flickers. I've had to unplug the battery because if I leave it connected a portion of the headlights remain on. I can still turn on my lights and use all electric functions without the key being in. Gonna have to tow it to the dealer and see wtf is happening.

Recap: Car had starting problems. Now it's sitting in my garage with a constant noise coming from the engine bay and weird electric occurrences that allows me to control all my electric features without the key even being in the ignition. Pls help.

Broke my brain trying to understand what's wrong with it. From starter to battery to spark plugs to fuses to the cold - does anyone have any advice or idea of what it could be?? Will keep updated.

 

It sounds like a battery issue. How old is the battery? Take it out and have it load tested by a battery shop or dealer. There may be several other things contributing to your issues. Battery cable connections on both ends, particularly the ground connection. Bad relay, short in the alternator, bad neutral or clutch switch could also prevent the car from starting. Go to nicoclub.com and download the service manual section on the electrical system for your car and start troubleshooting.

 

You're having classic symptoms of a wet IPDM.

-Power is on for various stuff without the car even being turned on.

-Failure to communicate with the ABS causing the ABS motor to run constantly, (temporarily you can unplug the 3 harnesses on the black relay box directly in front of the ABS valve block to keep from burning out the motor, just know you won't have ABS or traction control).

Also sounds like you're having either a battery problem or a parasitic drain problem, put the car on a charger and fill up the battery.

About the keys, the non-programmed key will allow you to crank the engine but not start.