Total System Shutdown (ignition)

[deskbound]

The trusted RX300, 2001 (petrol/lpg), had a sudden and catastrophic failure yesterday, in probably the worst place in the country, Tower Bridge London! It just stopped and on trying to switch it back on, ABSOLUTELY NOHTING, no cranking, no clicking, NOTHING. After what seemed an age, I had to push it forward (no one helped) with the aid of gravity into the side of the road just after the bridge (RED route, no stopping, no doubt I will get a fine too)

Recovery guy came and was confused too as the Battery, alternator, starter, cambelt all fine. Finally tracked it down to a blown 20amp fuse, marked AM2. Once this fuse is replaced, the car starts instantly, as it has always done. But rev the car a bit or put it into Drive and the fuse blows again and everything is dead again. Put in a new fuse and all is fine once more. This means that the car is undriveable and had to be piggybacked on the truck...a painful site :(

Question is why does this fuse keep blowing...are the wires from the ignition to this fuse shorting somewhere as you rev the car? I couldnt spot any loose/exposed wires. Is this going to be a monster problem of tracking down some issue in the wiring loom?? Recovery guy tried to read the engine codes but there were no faults stored at all. He spoke to Lexus who said "yes we have seen such ignition problems before", he offered to bring the car in, but they were not interested.

Any ideas would be most welcome. I am really scared of such electrical problems and am seriously considering getting rid of it, once it gets fixed.

thanks

[Duncan Roberts]

The trusted RX300, 2001 (petrol/lpg), had a sudden and catastrophic failure yesterday, in probably the worst place in the country, Tower Bridge London! It just stopped and on trying to switch it back on, ABSOLUTELY NOHTING, no cranking, no clicking, NOTHING. After what seemed an age, I had to push it forward (no one helped) with the aid of gravity into the side of the road just after the bridge (RED route, no stopping, no doubt I will get a fine too)

Recovery guy came and was confused too as the battery, alternator, starter, cambelt all fine. Finally tracked it down to a blown 20amp fuse, marked AM2. Once this fuse is replaced, the car starts instantly, as it has always done. But rev the car a bit or put it into Drive and the fuse blows again and everything is dead again. Put in a new fuse and all is fine once more. This means that the car is undriveable and had to be piggybacked on the truck...a painful site :(

Question is why does this fuse keep blowing...are the wires from the ignition to this fuse shorting somewhere as you rev the car? I couldnt spot any loose/exposed wires. Is this going to be a monster problem of tracking down some issue in the wiring loom?? Recovery guy tried to read the engine codes but there were no faults stored at all. He spoke to Lexus who said "yes we have seen such ignition problems before", he offered to bring the car in, but they were not interested.

Any ideas would be most welcome. I am really scared of such electrical problems and am seriously considering getting rid of it, once it gets fixed.

thanks

Embarrassing and indeed irritating but you should surely not get a fine if the thing had failed.

Assuming a search does not show up a thread, would you not be better placed getting this to a dealership to investigate (or an auto electrician/independent given its age and lack of warranty) and then advise us?

[Monster-Mat]

agreed id assume that if the dealership says it has heard of this before, then this is a fault, that can be sorted, but assume its a complicated one, or the dealer is just ****........

id go with the latter...

[deskbound]

Car is with auto electrician/my trusted mechanic now. Will post an update if we get to the botton of this.

thanks for the input

[Cymro]

Car is with auto electrician/my trusted mechanic now. Will post an update if we get to the botton of this.

thanks for the input

Please do keep us posted as to what caused your fuse to blow repeatedly - you've got me worried now as to whether my (identical) RX300 will suffer the same fate.

I hope it won't turn out to be too expensive for you.

I've just had the third (in 8 years) failure of an engine sensor, with its customary bill for £300!

[deskbound]

Still working on this folks...battery had totally discharged as the recovery guy had left the key in the ignition (just the act of putting the key in the ignition sucks up current and WILL discharge the Battery over 24 hours or so). Recharged Battery was put back in but the car refused to start...immobiliser had lost its settings I think??? Anyway have got it to start using the procedure detailed by Coiln Barber.

Still working on why the fuse keeps blowing...to kill the whole thing off once again.

[deskbound]

Update 2.

Car is cranking fine now but refuses to start (although fuse does not blow now). Strangely, the immobiliser light is flashing continuously (previously it used to go out when the key was put in the ignition). Could this be something to do with it now? ie the ECU is not allowing a spark to be generated because the immobiliser light is flashing??

Any iputs most welcome.

Looks like a long saga for me :(

Time to go buy a stop gap motor and definitely a pre 1999 basic, non electrics heavy one at that.

[Boxbrownie]

Have you tried the US forums for this problem, the UK forums seem very sparse on maintanence information.

Best of luck, defo keep us updated please.

Best regards David

[deskbound]

Ok the trusted steed is back up and running..no wiring loom issue, no heavy electrics no broken bits and above all, no massive bill!

Turns out that the problem was the ignition key itself. The fob and the blade had become loose in its casing over time (design issue I guess) and when the car had cut it out it was due to this which in turn blew the 20 amp fuse, which in turn meant that the car would not start.

The key fob and the metal blade HAVE to be in one piece for the car to start. The transponder in the fob sends a signal to the blade which sends it further down the line. Just using the blade on its own will NOT do and car will be immobilised, as it was in my case. The recovery man had used the key so vigorously that he had actually broken it clean away from the fob but didnt think this was an issue (apparently in some cars it isnt like Benz and Audi, as the transponder is in the key blade itself and not the fob).

The fix was to take it to Lexus, who plugged it in to switch off the immobiliser, then they ordered and recoded two keys and hey presto it fires up instantly. In fact it was also starting using the old key, but only when the key blade and fob were held tightly together whilst the ignition was being turned.

All in all a good result, and all for £200 (for 2 keys, whcih by the way look same as the old ones in terms of design. LX guy did say that Toyota Derbyshire know of this design 'fault' but havent really addressed it) To be fair the key did last 7 odd years. Faith in Jap engineering restored :)

[stringbender]

Thanks for sharing this information. I've dropped my keys quite a few times so will be extra careful from now on!

Alan

[Cymro]

Oh, that's a relief for you (and for me!). Thanks indeed for sharing this information. Whilst I hope that my RX300 won't suffer a similar catastrophic shut-down, it's good to know a possible cause, and a remedy.

£200 for two new keys is a good price - having lost one of my daughter's Skoda keys, I paid £147 for one replacement last week.

Cymro.

[deskbound]

Oh no!! It happened again...car died all of a sudden and that was that...another truck recovery to garage.

No faults found anywhere in the wiring. After much head scratching it was thought best to change the ignition starter (£63). Mech had seen this in a few other cars (Avensis and a RX300). New Ignition starter looks just like the old one, which showed no obvious signs of damage but was clearly only doing its job intermittently. Car is running fine now.

The replacement keys must have been a red herring, but I needed them anyway as they were broken.