Combination Meter Blackout Whilst Driving

[beskab]

Hi Guys

I am doing some research on a phenomenom that seems to be occuring on the series 4 /97-2000 LS400 in the UK

It manifests itself as follows.

Driving normally in any road conditions or environment when loss of electrical power occurs ,

affecting the direction indicators the instruments and lighting within the combination meter the audio

and navigation display.The engine and drive and braking behave normally.

The scenario persists until the ignition is switched off and back on at which time the problem dissapears.

Some members say that touching the ignition key during the event turns everything back to normal

but in most cases the key as to be turned to off and back on to achieve normal operations.

The general consensus is a faulty ignition switch but this does not occur through any pattern of wear and usage as my car as done only 25k and is only used on High days and special occasions some of the cars involved have done over 100k.

One member took his car to the dealership after the event and it could'nt be replicated or any fault found within the vehicle electronic analysis system,they were not looking specifically at the ignition switch at that time.

Because this is a fault that is difficult to replicate we are experiencing difficulty in getting Lexus UK to engage with us on this and they do not feel it is significant enough to warrant a recall or customer notification.

I can tell from my own experience which as occured twice now in the last six months that it is a very distracting and frightening occurence apart from the fact the instruments are dead there are no turn signals available and the head lights die as well.

I would be grateful if any members in North America and Canada who have experienced this scenario PM me so I can build a better case to confront Lexus with.

We are not after a free ride on this switch issue , my aim is to identify a potential dangerous safety issue and iradicate it before it causes a serious occurence.

[landar]

Hello Philip and welcome to LOC USA.

I have not personally experienced this issue but wanted to give you a potential troubleshooting tip.

So, you mention that turning the ignition key to off and back on restored operation. With all of the ECU's built into the car, would you not think that one which was being re-booted (restarted) might be the culprit? I do not see it as the ignition switch itself as much as an ECU. Possibly the Body ECU.

What I would be tempted to do next time this happens is to pull the Body ECU fuse instead of cycling the key. That would reboot the ECU and perhaps the lights would be restored. It would be a good clue anyway. It is going to take some time and patience to 'sleuth' this problem.

[beskab]

Hi Randall

Your diagnosis as been discounted through tests already tried .

The slight touching of the key as fixed the problem pointing to a misalignment of contacts .the ecu issue does not tie up the various electronic units and one owner had his vehicle codes tested at the dealership after a blackout and they found nothing in the check of the systems.

Further to that the switch is fitted to various toyota models and indeed other manufacturers vehicles and there have been reported incidents with those vehicles.

I appreciate your input but we are looking for other incidents concerning blackouts amongst Lexus car owners so we can get a definite pattern of the instances.

[landar]

Hi Randall

Your diagnosis as been discounted through tests already tried .

Got it. You have already determined that it is a faulty ignition switch. I wish you the best on your endeavor.