ScratchSF

In May, my car (1999 GS300) developed an intermittent problem where it would sometimes crank, but not start. After searching this site and others, it sounds like an immobilizer problem. I took it in over the summer and they changed the transponder coil around the ignition cylinder. That solved the problem for about two weeks and the intermittent problem persists.

The curious thing is that it might go for two weeks without a problem, and then I will have the problem for several attempts. (Actually, I've trained myself to look check if the security light goes off when I insert the key in the ignition - if it doesn't I'm destined to wait for the required 6 minutes.)

If this were constant, I think it is easier to troubleshoot. But because it is so intermittent it is hard to figure out. I will take it back in, but since their first fix didn't solve the problem, I don't want them just randomly trying things that may or may not work.

At this point, based on what I've read online, think I can look at wiring, the transponder amplifier on the steering column or the ECU. I think cost is lowest if a wiring harness problem and the most if an ECU problem.

Wondering what advice / recommendations people here might have?

MasterKwan

I'd try a different key. Try with ONLY the key and nothing else on the keyring.

You're looking to disassemble everything when it's not looking like a hardware problem to me. I'd try the simple stuff first.

ScratchSF

Have tried the two master keys as well as the wallet key. Have also tried without anything (e.g. a keyring) attached to the key. If upon the first attempt the security light comes on, it then doesn't matter which key I then use; I will need to wait the 6 minutes. I have tried using both master keys first; with the same intermittent result. So, I haven't been able to trace this back to being a key problem.

ScratchSF

I may have found the problem. I have a bridge toll transponder in my car, which I kept in my center console. I have now moved it to the left and keep it in the door storage compartment. Since I made the move, I have not had the intermittent problem I described in the original post.

While I'm not will to claim victory yet, the problem hasn't repeated since the first of December, when I moved the transponder. So, I am feeling pretty positive that this was the problem.

Posting in case someone else has this intermitting problem. This would be something to look for.

Rara1989

im having the same problem i don't know what to do sometimes it cranks and runs sometimes it don't it sits and try's too but the security light is on