2006 Mazda3 Won't Start / Immobilizer Question

Hi everyone, I'm new here.

I have a 2006 Mazda 3 and it will not start. It was working fine for the most part, but I started having some issues starting it recently when I had to turn the steering wheel and unlock it to start the car.

Now, it has gotten to the point that it will not start at all even if I turn the steering wheel. I got to turn on briefly for one day and I had the parts store run the scanner on it and they confirmed that the battery and starter are in good working condition. So, in that case the most likely cause is the immobilizer/anti-theft system. There is a red light with a key that blinks in my instrument cluster that keeps blinking even when I unlock the car and try to start the car. The lights and radio will turn on, but it just clicks when I try to start it.

I called the dealer about this and the service tech told me I might need to have it reprogrammed so the best option is to purchase a new key from a locksmith.

I just have a basic transponder key with a metal portion that unlocks the doors and starts the car. I don't have a key fob or anything like that.

I really need to figure out how to get my car to start again, so any advice would be helpful. I have tried to remove the battery terminals, I tried leaving the key in the ignition for a certain amount of time reprogram it, I tried locking and unlocking the doors a number of times, but nothing has worked so far.

I just need to figure out how to disable the immobilizer or reprogram the system or the key to get it to start consistently.
 
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2014 Mazda3 S GT auto, 2008 MX5 6-speed
How did they determine that the starter is okay? Typically you would remove the starter before bench-testing it. Some people will tap the starter solenoid with a hammer to see if that frees it sufficiently so that it will start.
 
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2010 Mazda 5 Sport
Could be battery cables. A slow degradation of the car starting often is the circuit going bad between the battery and the starter.

The fact that you get a CLICK when you turn the key makes me think the ECU is saying the key is OK. I *THINK* (but may have forgotten), that NO CLICK happens with a new unprogrammed key. The ECU says NOPE not a valid key and I won't energize the starter relay.

Getting a CLICK makes me think of a few possibilities:

#1 the starter relay is getting enough power to engage, so it's not a key issue.
#2 There is not enough juice to make the starter go. Starters take a TON of current compared to EVERYTHING else in the car.
#3 the starter is bad and no amount of juice will kick it over.

Based on that:

#1 - Might mean key is ok if the CLICK is the starter relay. If not the starter relay, then maybe key is not programmed.

#2 - Bad battery cables, ground connection, bad connection to starter. Cables can rot out from the inside out. Disconnect from the battery and bend them a good bit. Do you hear crackling inside? Is there major corrosion on the terminals? This needs to be addressed first with new terminals and/or new section of battery cable. Check connections to the starter and body/engine grounds.

#3 - If the problem hasn't been found by #1 or #2 then a new starter may be needed.

Honestly, you should just take it into a dealer and get it looked at. They should be able to figure it out quickly, the starting system is fairly straight forward. The only complication is that the key needs to be programmed to the ECU. I doubt that programming was lost though.

Why do you not have a key fob? You should have multiple sets of keys/fobs. It is actually useful for troubleshooting and not getting stranded. Luckily they are not that expensive for this car. New cars, the fobs and programming run about $600 each now.
 
I had an issue with my 2010 mazda 3 where the car wouldn’t recognize the transmission was in park. If the car isn’t in park it won’t start. This could also be the source of your issue. This wasn’t a bad fix for a mechanic to solve (The lines in the gear selector get stuck).