KendalG

Bought this car a while back, it's been fine up until the past few months, then everything went south. Have done LOTS of repairs, and down to the final stretch, I think.

What I have done.
Engine wiring harness replaced
Starter
Alternator
Battery
Plugs
Coils
Evap core

So, at this point everything's put back together, but it still won't start.

The fob will lock and unlock the car. The anti theft light on the dash by the windshield blinks but never goes out. With the fob in range the security light on the dash goes green.. green box with the key inside. The ignition will turn from OFF to ON, and then ACCESSORY fine, and all that works. When I try to start the car, the light on the dash goes solid red. Red box with a key inside. Have checked all fuses visually and with a probe, everything that should get power does. Did not use a volt meter because the light on the probe was bright and steady.

Checking codes with an OBDII shows only one code, P0075 - Intake Valve Control Solenoid Circuit Bank 1. A locksmith I'd contacted about programming new keys said he thought it was a bad ECM and recommended getting an ECM from a junkyard and getting it programmed. I'm not sure if it's the ECM that's bad or the immobilizer that is keeping it from starting. I've seen sites that say a used ECM cannot be programmed to my VIN, but then there are many places where you can buy a refurb ECM programmed to your VIN.

Is there a way to determine is it the immobilizer that's not reading the key, so it doesn't send the right signal to the ECM and the car doesn't start, or because of the code, is the ECM not getting proper voltage and that's the issue?

I got this car for cheap off a high school kid who'd clearly done a ton of work (poorly) and now I'm chasing down his eff ups. This is the last hurdle, getting the thing to turn over and run.

TDGrant

My guess is that it is the key. I went to my uncle's, and when I tried to leave, the car was dead in the water; crank all day but would not even try to start. Towed the car to the dealer and they reprogrammed the key. Its been good ever since. Why it got corrupted...they had no explanation.

If you send it to the dealer, then make sure you have any additional key fobs with the car so they can reprogram them as well.

KendalG

I called a locksmith to program two keys. He refused and pointed me to either ECM or immobilizer. His experience being it was rarely the key itself and one of the other two. The immobilizer sounded like a safer bet based on my description. Called a couple local shops, they said same thing. Replacement immobilizer on the way and fingers crossed.

Costee

Keeping the fob far away from the car, have you tried starting the car with the mechanical key? What do you mean by the immobilizer? The immobilizer is integrated into the BCM.

KendalG

I've tried to start it with the physical key, but the fob is in the car. The immobilizer is attached to the ignition cylinder. It's a ring around the ignition cylinder that reads the transponder code of the key. If the immobilizer doesn't give the ECM the all clear signal.

Costee

Try out the key with the fob out of the way, and revert. No, for your car the immobilizer is in the BCM. The ring around the ignition is the antenna that receives and sends the transponder code to the BCM.