Dash Warning Lights On

[KUDOS]

It's KUDOS here from New Zealand - after owning the car for 6 years I have my first problem and need some help.

I have a 1990 Celsior (LS400) done 180,000km and runs as a LEXUS should. Recently I have been having an intermittent problem with dashboard warning lights coming on. Lights up like a Chrismas tree.

It only seems to happen when I accelerate hard - foot on the floor. Although it has happened a couple of time in heavy traffic. During a 2 hour drive yesterday I was able to make the warning lights come on by putting my foot to the floor. When I accelerate hard 5 warning lights come on, bulb out, Battery condition, cat converter, oil level and radiator level. I think the fuel gauge drops slightly as well. On the return trip - still at 120-130kph but no real hard acceleration - no lights.

No problem with the way it performs when this happens. If I back off they go out after a few km.

Fluid levels are OK, Battery seems OK.

My thoughts are low voltage - but its and idles no problems.

Possible problem with the transmission - maybe getting too hot when pushed hard.

Can anyone help???????

[ROYT]

Have you checked for the popular fault of broken wires in the boot lid hinge?

This gives weird problems but the only time I had the fault you describe [not on my Lexus]

it was a faulty Battery....

[steve2006]

Hi,

Welcome to the LOC.

As Royt says check the boot hinge wiring 1st.

It may also be helpful to read the fault codes which with this car is fairly simple with no code reader being required.

If you need the info on how to do it let me know.

BTW whereabouts are you in NZ? always interested so I can have a look on Google Earth.

Cheers.

[ManicMark]

Could also be to much Voltage I had the same problems with a Vauxhall I owned 15.7 volts at high revs. voltage regulator was shot.

[KUDOS]

Thanks guys.

I've just got back from another 5 hour trip.

No problems while driving at steady speed with modest acceleration. When I did floor it in power mode so that it kicked down 2 gears and reved out on came the lights. Need to try it with power mode off.

They also came on when I loaded up the electrics at a steady speed, lights and fan on high. They went out when I turned the lights and fan out - usually takes about 6-8 km. This would make me think low voltage, but under hard acceleration when it gets up to 5-6000 rpm has me stumped.

Steve2006 - I live in Churton Park in Wellington. Not sure on how to read the fault codes. My AC/clock LCD panel has the usual problem, so if they are displayed there I can't read them.

My AC/clock LCD is different to any other I have seen and I'm not sure if I can replace it. The car has the full rear seat kit - heated, massager, full electric adjustments. Full AC controls in centre rear arm rest etc.

KUDOS

[ManicMark]

Thanks guys.

I've just got back from another 5 hour trip.

No problems while driving at steady speed with modest acceleration. When I did floor it in power mode so that it kicked down 2 gears and reved out on came the lights. Need to try it with power mode off.

They also came on when I loaded up the electrics at a steady speed, lights and fan on high. They went out when I turned the lights and fan out - usually takes about 6-8 km. This would make me think low voltage, but under hard acceleration when it gets up to 5-6000 rpm has me stumped.

Steve2006 - I live in Churton Park in Wellington. Not sure on how to read the fault codes. My AC/clock LCD panel has the usual problem, so if they are displayed there I can't read them.

My AC/clock LCD is different to any other I have seen and I'm not sure if I can replace it. The car has the full rear seat kit - heated, massager, full electric adjustments. Full AC controls in centre rear arm rest etc.

KUDOS

Have you checked with a volt meter what readings you are getting at tick over & at high revs, should be around the 13.5 to 14.5 volts mark.

[steve2006]

Hi,

Thanks for your location I will have a look later on Google Earth.

You don't need the LCD to be working to get the fault codes as it is the blinking light system.

Here is a link to Lexls ( very useful site) on the fault code proceedure.

http://www.lexls.com/tutorials/intro/codereading.html

With having the rear massaging seats it sounds like the top range spec model do you have air suspension or coil springs?

You can get the LCD modules from the USA for RHD models if you are confident on replacing them.

With the problem you appear to have it does sound like an alternator problem, the power steering resevoir seal fails and the fluid gets in the alternator have a feel around below the PS pump to look for tell tail signs.

As ManicMark suggests if you have a digital voltmeter measure the Battery voltage on the terminals at tickover speed then get someone to hold the revs high and see if the voltage increases significantly.

What kind of temperatures are you getting in NZ at the moment?

Cheers,

Steve

[KUDOS]

Thanks Guys.

I'll put a volt meter on the Battery today. I did check it with the engine off and it was around 12.5.

The power steering pump is OK -no leaks - I've not had to add a drop to it since I've had the car.

The AC/clock LCD display is quite different to others I've seen. It's only about half the size of the radio one. My dash has a set of controls in the top left for the rear AC. The car has the air suspension. I suspect it was set up as a chauffeur driven car. The front passenger set folds up and moves into the foot well to give more rear leg room and better forward vision. Rear seats have a console with a full set of controls for the AC and stereo.

Temperatures here at the moment are around mid 20deg C.

[KUDOS]

I've been out and checked the Battery, and it looks OK to me.

At idle (650rmp) and no load it 13.8 volts.

Turn all the lights and fan on high and its 12.8 at idle. Take the revs up to 1800 and its 13.8.

[ffcary1]

From those figures that you quote then the problem is not the alternator, it would suggest that the rear boot hinge loom should be your next point of investigation, check for broken cables as this is the looms weak point. My rear fogs dont work and when the weather improves then i will attack mine. Good luck and let us know how you get on.

Gary

[KUDOS]

Thanks - I'll check the rear loom.

An auto electrician friend has suggested that seeing I can induce the problem with hard acceleration and high revs that it could be the brushes and at high revs they are skipping or bouncing.

I think it may be time to pull the alternator out and have it serviced.

[Haylands]

Hi

Alternator brushes are unlikely, if you want to test them then measure the voltage at a much higher revs than 1,800... somewhere around 6,000... it will sound very harsh but will not harm the engine to rev it like this with no load for a short period of time... The reason I say I don't think it's this is because the Battery should have enough in it to run the engine at high revs if the alternator is failing then.

I agree with the others, first thing to check is the boot loom, if that is OK I would check the engine earth, if the earth is poor then it will suffer at high demand, i.e. high revs. This is easy to check, get a pair of good quality thick jump leads and fix both to the negative Battery terminal and then to different parts of the engine, try the car and see if the problem is still there.

Don't just spend money having things rebuilt because someone else thinks it might be it, if the above prove fruitless then get the car checked by a qualified electrician who will find the problem, it may cost a few bucks but it will be cheaper than just rebuilding everything....

Good Luck and let us know how you get on

Pete

[KUDOS]

Where does the rear loom give problems? Where it bends round the boot hinge? I've had a look and there are no obvious problems. I have found 1 of the number plate lights is out - any idea how to remove the bulb holder?

Cleaned the Battery posts and connections and volts at idle have gone up to 14.

KUDOS.

[Haylands]

Hi

You cannot check the wiring just by looking at the outside of the loom.... here is an old post from steve2006

"Go straight for the wiring loom that passes over the nearside (RHD) boot lid hinge, it is wrapped in a black plastic sleeve, carefully open it up and look and feel for damaged wires, repair as required and retape.

Apparently when the cars were built they were not too generous on the wire lengths and the opening of the boot over time causes breaks to the wire inside the insulation (having said that it seems to take 14 years to cause a problem!)."

Even wires that look OK on the outside plastic could be broken inside, you have to feel and check every mm to see if this has happened or use a continuity meter and probe them.

Do a search for "boot hinge" and you will find details, look on the USA site as well. There is loads of info about it, it gives the symptoms yours has... funny dash lights as well as sometimes loss of power... the wiring here is not just for the rear of the car...

Pete

[Leadfoot]

Gidday Mate, always nice to have another Kiwi on the boards!

(Steve, I'm based in Whangaparaoa if you are looking on google earth Lat -36.582993° Long 174.664193°. Check out my new motorway!)

Given your cars age and the description of the problem hopefully it is related to the classic trunk wiring loom fault. Usually the fault occurs when you brake though, the short circuit backfeeds voltage into the ECU in an unexpected way and she gets upset. You state that it always occurs on heavy acceleration, which implies that the kickdown may be involved. I will have a search through the boards (this and the US one are a treasure trove!) and see what we can find. The transmissions are pretty tough, it is more likely to be an electrical gremlin than overheating from SPEEDING!!!.

Good luck, and please post any fault codes if you get them. The proper procedure is to read them, wipe the memory by pulling the EFI fuse for more than 15 seconds, then plug it back in and take it for a drive to get the problem, then read the fault codes again. The lexls site is a goldmine.

Good luck.

[steve2006]

Hi

You cannot check the wiring just by looking at the outside of the loom.... here is an old post from steve2006

"Go straight for the wiring loom that passes over the nearside (RHD) boot lid hinge, it is wrapped in a black plastic sleeve, carefully open it up and look and feel for damaged wires, repair as required and retape.

Apparently when the cars were built they were not too generous on the wire lengths and the opening of the boot over time causes breaks to the wire inside the insulation (having said that it seems to take 14 years to cause a problem!)."

Even wires that look OK on the outside plastic could be broken inside, you have to feel and check every mm to see if this has happened or use a continuity meter and probe them.

Do a search for "boot hinge" and you will find details, look on the USA site as well. There is loads of info about it, it gives the symptoms yours has... funny dash lights as well as sometimes loss of power... the wiring here is not just for the rear of the car...

Pete

I'm now so famous I get quoted! Where's my Golden Globe! Got to go now and finish my latest blockbuster novel LOL.

Hi Marcus I take it you're in N.Z. at the moment mid 20s very nice!.

[KUDOS]

Thanks for the help everyone.

I've got as far as taking out the boot lining and stripping back the wrapping on the loom - trouble finding time.

Leadfoot

I have also had them come on when I brake and had them go out when I brake?? Does seem to point to the kickdown switch and brake lights.

I've got a numberplate light out - any ideas on how to remove the numberplate bulb holder??

KUDOS