lexo1998

For about a couple years now my 1998 Lexus Gs300 wont start right away. Sometimes I have to leave the key on the on position without starting the car for about 10 minutes till it finally shuts off the anti-theft so I can start it. I've fixed all the door acuators so all my doors lock and unlock properly, I had a new key and fob done neither thing has fixed this problem. Ive put a new key amplifier and key ring cylinder still no luck. Is there a way to turn off the immobiliser or to bypass it. Or can someone tell me how to fix this problem? I would really appreciate any help thank you!

vijayn

Also check the wires between the Transponder key amplifier and engine ecu. It could have bad signal wires or the 12V or 0V supply is bad on the amplifier.

Have you confirmed that the starter circuit is all good? (fuse, relay, ign switch, stater solenoid and starter motor)

lexo1998

Thanks for the help Vijayn im going to make some time to check out what you said. By any chance do you know if i can disconnect the anti-theft feature or the immobiliser? thanks once again for the advice ill let you know if i find anything

vijayn

Happy to help mate,to my knowledge I dont think you can disconnect the anti-theft devices. I'm pretty sure that the code that gets transmitted from your key to the transponder amplifier module gets converted further to a signal that then gets sent to the Engine ECU. After this happens and its the correct code, only then will it allow you to start the engine.
So I'm not sure if a new transponder and key would work either as it is coded to a specific engine ECU. You would probably have to get the transponder, key and Engine ECU together.

I could be wrong though, as these cars were at the early stages of when transponders came out so it may not be that advanced.

AndyRX300

Hello mate i was hust wondering if you ever figured out the probelm or got it fixed? I have the exact problem with my rx300 and any help would be much appreciated!!

Thanks

Andy

burteboy

Does your car has a remote start.? If so that's the problem, just use the remote start. The key in the remote start is causing the problem . The car being confused thinking it's being stolen so it shut down the vehicle. Leaving the key for awhile eventually it will be reconizethe security light will go out and you can start. If you don't have a remote start try programming another key and try that.

Johnhett

I have the remote start in my 99 gs300, I get the same issue occasionally while using the remote start. It doesn't matter key or remote start. Turns over, light stays on, car stays off.

scott802

Hello all,
I have the same issue with the immobilizer not going off and the car will not start.
I've changed batteries in both keys same problem.

What are the chances this is the amplifier or key ring cylinder versus the entire ECU?

My local trusted Lexus tech said he doesn't want to 'throw parts' at it without knowing the issue 100%. It's frustrating because I'm afraid to drive it as it will leave me stranded from time to time.

Are the amplifier and key ring cylinder expensive parts? Wondering if anyone else has had the issue, and resolved it if so what was the cost of repair?
If it's something I could do fairly easily myself I would do so.

Thanks very much

Scott

phantomgray

Hey Scott, my family has been dealing with the same issue going on 4 years now, does you're car not start at all right now? or is it random? Also, do you have to leave the keys in the ignition for a certain period of time for it to "read/reset"? It seems we are a rarity even though i did come across someone on craigslist not too long ago selling theyre car for parts with one of the main reasons being this issue(sad). Later on this week or next week i'm just going to have it reprogrammed/reflashed i believe is what it's called by a mobile auto locksmith that was referred to me by a friend who says this guy knows alot about lexus. So instead of going to the stealership and have them do it, i will let the mobile guy give it a shot since he has the software and knowledge. If that doesnt seem to help/fix it, another type of mobile locksmith said he would check the signal power of the antenna by the key ring/ignition area and go from there. One of the two locksmith said that's something that usually "doesn't" fail. I have also tried sending out my ecu to one of those places that connect them to theyre scanners and or visually inspect to see if there's any codes or issues and it came back to me saying there was nothing wrong. I will let you know what's up with my results or you can reply to discuss more details.

scott802

Hey there, I can't believe you've had the same issue as I have. It doesn't seem like anyone has any answers.
I will say, I already tried reprogramming the key at a locksmith. The problem I have is that for some reason I do not have a master key. All I have is 2 valet keys apparently. I've owned the car for 15+ years so I have no idea how this happened. The locksmith cannot do anything without a master key.
So what I'm left with is this
1. Replace the entire ECU and have brand new keys made off the new ECU. I saw ECU's on ebay for 200-$500 so I'm not sure why my local Lexus tech (not the stealership either) told me it would cost in the 'thousands'.
2. Change the amplifier and key ring cylinder. Not that expensive apparently.
3. Leave it as is, which means the car isn't driveable reliably. It basically starts 50% of the time now. It will frequently just briefly catch with the immobilizer light off then it immediately dies as the immobilizer light comes back on.

No pattern that I can tell. The local Lexus tech even put a code reader on it and the error code it throws is some ambiguous 'error' which apparently doesn't narrow it down enough so he can't tell whether changing the amplifier and key ring cylinder would even work. He did tell me it's extremely rare for the ECU to go out. That doesn't mean it can't happen, but it's rare.

At this point I'm stuck with a car that's treated me so well all these years but it's pretty useless now. I'd sure like to know what others have done and if changing out the amplifier and key ring cylinder have worked for others. My plan is to (if I can get it started) just drop the car off over at my local shop I've been using and tell them to keep it until they can give me an accurate resolution, they said they are willing to do that. I just intend to tell them I'm only willing to pay 1 hour of diagnostic time so I don't get robbed.

Any other ideas?

Thanks

Scott

scott802

My local shop just confirmed it's a bad ECU. They want $1200 for another ECU and $600 labor to put it in.

What? How hard can it be to swap this out??? Anyone?

Thanks,

Scott

phantomgray

Hey Scott. I'm still dealing with the issue and had talked to the mobile mechanic over the phone and we discussed that it might not be worth his time and my money to have it reflashed. He doesnt think that's the problem. So the fact that you said your shop said it was the ecu, did they say how they came up with that decision? 600 in labor does sound like more than you would think. I'm assuming it would be plugging it in and syncing up the keys?

JohnGalt1

@scott802 @phantomgray I had the same issue on my '98. $600 labor is absurd, it was 20 minutes to remove the glove box and the ECU.

I had my ECU "rebuilt" however it didn't fix the issue I was having with my immobilizer (codes B2796&B2798). Essentially my car would crank but not start. My solution was to have a locksmith remap the ECU and disable the immobilizer. The only downside is that when you disconnect the battery you have to disconnect the top plug of the ECU and then restart the car. Reattach the top ECU plug and you're good until the next battery swap in a few years.

What we do believe to be the issue on mine is not the ECU, however the key transponder amplifier(Part # 89783-50050) which is no longer available. I have a query set on Ebay and am checking the scrap yards regularly so that if I find one, he can remap the ECU to stock after it is installed.

Hope this helps.

phantomgray

Oh thanks for the info John, that's what i heard as well as far as amplifier, also something about the antenna within the area. He did tell me to look at junkyards as well, i guess he knew about it not being made anymore rather than just cheaper. I will keep the page updated if any major changes. One thing i did recently notice was the light was not going off even after an hour or so on 2 different attempts to start it within 2 days and on the third day i went to start the car and the battery was low/almost dead, so i started to think maybe the problem was getting worse with a weaker battery, i then started to put my charger on it throughout 3 weeks on the weekends on a 2amp trickle charge. I started to take readings of my battery at different times and researched when i purchased my last battery, it was 3 1/2 years with 84 month warranty, so i took it in to my local lexus dealership and they prorated it. Of course has been starting with no problems but i still don't dare to take it on a short trip to see if it will have a no start issue becuase i don't want to jinx it.

phantomgray

lol nevermind, i knew i jinxed it just by talking about it, my car has been in the garage all day due to no start, maybe it's finally failing