Vexing alarm problem

[MartinH]

Neither smart key will open car remotely. Use mechanical key to open — alarm starts, with flashers. Engine starts when dashboard Start button is shown smart keyfob, but alarm and flashers continue, ceasing only after the automatically-set period. This is a repeatable cycle.

Is anyone able to diagnose this? And, even better, to offer a prognosis?

It is beyond vexing because my wife needed the car to come and pick me up from hospital, where I've been for the last week — behold me taking the train home. This is very much not the Lexus experience we expect!

[johnatg]

I assume you've tried new batteries in the fobs? 

[MartinH]

Both smart keys fail identically — were supplied new by Lexus Edgware Road as part of last year's rebuild. For both to fail at exactly the same time would be a surprising coincidence. But it's not impossible I guess.

[ColinBarber]

sound like interference is stopping the fobs working if the batteries are ok. Move the vehicle to see if they work elsewhere.

[MartinH]

That's possible. It's not parked where it usually is.

[PCM]

11 hours ago, ColinBarber said:

sound like interference is stopping the fobs working if the batteries are ok. Move the vehicle to see if they work elsewhere.

+1

Had a similar problem.

The ONLY way I fixed it was to switch ALL the power off in my house at the fuse box, and switch it all back on again.

Bizarre as it sounds!

[MartinH]

Bizarre indeed! But the car is not parked outside my home — we live in inner London, so never any chance of that.

Lexus Edgware Road concur with @ColinBarber that it may be some extraneous RF interference. By and by I shall gird my loins to move the car, shrieking and flashing, to a different parking location and try again. But shall I be able to find a legitimate parking slot? That is by no means assured, where I live. It is indeed a vexing problem!

[MartinH]

So here's the conclusion. I rummaged around among my spares and found a pack of CR1632 batteries, installed one, went to the car, all normal. Got in. Drove it.

So I guess that the brand-new key fobs, supplied at eye-watering cost as part of last year's electronics and fuel-system rebuild by Lexus Edgware Road, were just taken off the shelf and not fitted with new batteries. Talk about spoiling the ship for a ha'porth of tar!

[Mr Vlad]

Blimey. Personally I'd get hold of them cowboys and tell them of your stress caused by their negligence and get compensated c/o a free service and MOT.

[Texas]

Fault finding 101, always start with known good parts ( even new out of the box parts have been known to be unserviceable!).

Glad you got it sorted ( cheaply) and as the key fobs are ‘always transmitting’ I change the batteries every year with Panasonic ones from eBay for pennies! So hopefully negate ever having such calamities!

[MartinH]

But here comes the curveball: having parked the car (very nearly) outside our home, I took the other keyfob out to check its operation, without having replaced the Battery. And guess what? It works perfectly.

[johnatg]

I'd guess that the original problem was caused by interference which has gone away so your fob worked anyway - eg some equipment has been switched off. Hopefully where you're parked now is not going to suffer from interference. Worth remembering that this can happen though.

Anyone got any tips for overcoming such interference if you need to?

[MartinH]

3 hours ago, Mr Vlad said:

Blimey. Personally I'd get hold of them cowboys and tell them of your stress caused by their negligence and get compensated c/o a free service and MOT.

To be fair, it looks as though the problem were not of Lexus Edgware Road's making, rather that it was set off by an unusual, localized RF hotspot. But it did cause a great deal of anguish because my wife was all set to come to pick me up from an unscheduled and worrying 8-day stay in hospital. She has never had to unlock the car using the mechanical key, so I had to talk her through it, with the car shrieking like a banshee. It was not a good moment.

[ColinBarber]

26 minutes ago, johnatg said:

Anyone got any tips for overcoming such interference if you need to?

There's really not much you can do. If you know where it is coming from you could try and block it with some sheet metal / foil, but that's not really practical.

If it is persistent (and not of your own doing) then reporting to Ofcom is all you can do - if something is interfering that isn't near the vehicle then it is almost certainly operating above permitted power levels and therefore Ofcom have the powers to get it shut down/prosecute.

[Texas]

The fresh batteries might have made your fobs signal of better strength than that of the interference.

[Las Palmas]

Today I read: Remote key Battery low

or something like that. Was changed by Lexus service 6 months ago. Rather short life for a Li-ion bettery.

Seems Lexus/Toyota are selling old batteries at tripple price of fresh from supermarkets.

CR1632

[MartinH]

Well all this stuff about vibes in the air is so much baloney. About six weeks ago, the car again failed to start. Tried both keys, nothing. RAC called, their tech puzzled over it, said Battery was all good, must be deep-seated electrical problem (again). Trailered back to Lexus Edgware Road — their hearts must have sunk to see the same car again after its three-month sojourn in their workshop last year.

UX loaner offered without demur, lead tech goes back to work on it (he must know this green IS250 better than any of his customers' cars by now) and eventually diagnoses...

A blocked drainpipe from the sunroof surround!

Water leaks out into the engine bay and fritzes the electronics. I was most unlucky, the tech said — he had never seen this on an IS250 (tho he had seen it on several RXs). Remedial work was done under guarantee of last year's work, so that, together with the loaner for a planned trip to the country, makes me a happy customer of Lexus Edgware Road. Nobody ever said they were low-cost however!