Trying To Save A Lovely Classic From The Scrapyard

[fuddymucker]

Hello everybody

I have just bought a 1993 LS400 with only 66000 miles on the clock, problem is I bought it at auction and the engine light is always on and it wont rev above 2000rpm.

I know these engines are bullet proof so at that low milage I'm guessing it must be a faulty sensor or something, is this a common fault?

Cant find anything by searching the forum except how to reset the ecu, as soon as I restart the engine the fault light comes back on..

If it is a terminal issue it will go to the scrapyard but would be a shame if its because of a £20 sensor or dirty probe somewhere.

Thanks

[Chris Skelton]

Hold on! I'm sure someone will help!. Can't be anything TOO serious!

Plenty of scrappers around once you find the fault, if needed!

treasure it. Not many folk can cruise about so smuggly!

[fuddymucker]

While trying to read the fault codes I hit a problem before I start

1. The malfunction indicator lamp will come on when the ignition

switch is turned ON and the engine is not running.

HINT: If the malfunction indicator lamp does not light up, proceed

to troubleshooting of the combination meter (See page

BE−194).

2. When the engine is started, the malfunction indicator lamp

should go off.

Well the light does not come on with the rest of the ignition test lights but it does come on when the engine is started...

Guess I need to find page BE-194?

- Show quoted text -

[stani1029]

I had a problem like this before on a micra where it would only rev to 3000rpm. A throttle body swap fixed this, i cant tell for sure if its the same on a lexus.....

[steve2006]

First of all welcome to the LOC

Ok the 1993 model has the "paperclip" diagnostic system so you don't need a fault code reader just a shorting link and read the codes as blinking lights,the link below explains the proceedure.

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

You need to do this 1st to gain an idea where the fault may be.

If you get to the point of scrapping the car let me know first I am always up for a challenge.

[ROYT]

page BE-194 is all about engine oil level warning including switch and combination meter

circuit plate...

[Malc]

I don't believe for one moment that benfur on here wouldn't have the answer !

It's bound to be something silly and trivial: What's the rest of the car like ? immaculate maybe !

Malc

[mike213735]

Again, not sure about Lexus, but on the Vauxhall Omega this would definately be the Crankshaft Sensor.

Thanks

Mike

[fuddymucker]

page BE-194 is all about engine oil level warning including switch and combination meter

circuit plate...

Thanks ROYT, does anyone have a copy of this page they can send me please

[fuddymucker]

I don't believe for one moment that benfur on here wouldn't have the answer !

It's bound to be something silly and trivial: What's the rest of the car like ? immaculate maybe !

Malc

The rest of the car is not perfect and looks like it has been unloved for the last 2 years

ding on front ns wing, smashed os rear boot light where the boot lock has been beaten out and all bumper corners have been scratched.

On the plus side every internal luxury electric works and the interior is clean. Also she drives smooth as silk even if only up to 2000rpm the ride quality is like nothing else.

[Malc]

17 years old and a few body dings and bumper scrapes, well, that's not so bad really. I guess the car only cost a few hundred £squid maybe ?

And you could spend £80k and still get body dings and bumper scartches in the first few days !

You might actually have the bargain of the month !

Malc

[fuddymucker]

Well I have spent all day trying to sort this issue..

I have removed every fuse and checked them all, all OK.

I have blown out the air filter with a high pressure line and it looks

much better.

I have removed and dismantled the display cluster, cleaned all

connections and boards with electrical cleaner and reassembled, still

no check light on ignition).

I have disconnected all ecu plugs and cleaned with electrical cleaner, no change..

If it would only display the fault code I would stand a much better chance of sorting it, but I am just having no luck getting the engine check light to show when the ignition is turned on, do you actually need the engine running to do this code finding? or will I damage a computer somewhere when I short the terminals out with the engine running?

Can someone else please test this on there LS400 (mine is a 93), go out turn the ignition on and see if you get the engine check light symbol displayed.

Many Thanks

FuddyMucker

[steve2006]

Hi,

Just checked my 1994 (same model) and the engine management light does come on with the ignition then goes out when the engine is started.

I wouldn't think checking the codes with the engine running would create any problems the ECU is live when the ignition is turned on so the only difference is the engine actually running.

Is the engine running on all cylinders?

it sounds like it is in LHM (Limp Home Mode) with it only revving to 2000, the AFM does fail on this model so it may be worth checking.

[ACLex]

We had a similar thing on a GS300 recently and it turned out to be an airflow meter :) worth a try.

Andy

[SteveLS400]

Well I have spent all day trying to sort this issue..

I have removed every fuse and checked them all, all OK.

I have blown out the air filter with a high pressure line and it looks

much better.

I have removed and dismantled the display cluster, cleaned all

connections and boards with electrical cleaner and reassembled, still

no check light on ignition).

I have disconnected all ecu plugs and cleaned with electrical cleaner, no change..

If it would only display the fault code I would stand a much better chance of sorting it, but I am just having no luck getting the engine check light to show when the ignition is turned on, do you actually need the engine running to do this code finding? or will I damage a computer somewhere when I short the terminals out with the engine running?

Can someone else please test this on there LS400 (mine is a 93), go out turn the ignition on and see if you get the engine check light symbol displayed.

Many Thanks

FuddyMucker

Have you taken the advice from steve2006? If you follow the instructions in the link http://www.lexls.com/tutorials/intro/codereading.html it says to set it up and turn on the ignition, not start the engine. If you haven't done it have a go, then come back with the results. It sounds like the car is in "get me home mode.*

[fuddymucker]

Hi Steve2006 thanks for doing the test for me :) I also think it is in some form of limp home mode but I don't know what AFM stands for sorry.

Hello SteveLS400, yes I have followed it to the letter but still no engine check light.

Just to be sure I'm not getting my symbols mixed up, when I say engine check light I'm talking about the orange symbol thats shaped like an engine (I have no hand book sorry)

[ManicMark]

Hi Steve2006 thanks for doing the test for me :) I also think it is in some form of limp home mode but I don't know what AFM stands for sorry.

Hello SteveLS400, yes I have followed it to the letter but still no engine check light.

Just to be sure I'm not getting my symbols mixed up, when I say engine check light I'm talking about the orange symbol thats shaped like an engine (I have no hand book sorry)

Have you tried disconecting the Battery neg terminal with the ignition switched to acc position leave it for 20 secs & reconect it. this cancelled the limp mode on my vauxhall omega may work on your ls400 to. yes the orange light like an engine is the management light. Good luck Mark

[steve2006]

Hi Steve2006 thanks for doing the test for me :) I also think it is in some form of limp home mode but I don't know what AFM stands for sorry.

Hello SteveLS400, yes I have followed it to the letter but still no engine check light.

Just to be sure I'm not getting my symbols mixed up, when I say engine check light I'm talking about the orange symbol thats shaped like an engine (I have no hand book sorry)

AFM is Air Flow Meter and the unit is between the air filter box and the black ducting which goes towards the engine inlet manifold,it is made from alloy and has an oblong shaped black box attached to it,check the wiring loom and plug to it.

There is no easy way to test it without specialized equipment but it is a known failure item,there is a member on the forum who would be able to supply a known good one but if you could access the fault codes it would save the guesswork.

[steve2006]

Just had a thought,have a look under the bonnet as there is a duplicate code reading port under there as well as the one under the dash,it's on the right hand side on top of the engine and oblong in shape,flip off the cover and see if anyone has left the shorting link in place as this may be upsetting the EML.

[fuddymucker]

Thanks Steve2006

When you say it is a duplicate code reading port, does it do eveything that the one does inside the car But its just a diffrent shape? If so do you have a diagram of each connector TE1 + E1?

[fuddymucker]

Ok I have checked the diagnostic port on the engine and WA and WB have a jumper on but it looks like a proper jumper not a piece of wire. Can someone check there port to see if these are jumped as standard please

[TigerFish]

The picture in this thread tends to suggest that Wa/Wb are normally linked.

http://www.lextreme.com/forums/showthread.php?p=102167

[fuddymucker]

Cheers TigerFish, that was really helpfull to see the same jumper in the same place as mine, also it is intresting to see the socket looking so bad as mine looks the same, guess it is some sort of waterproofing on the spades and not just muck :)

[steve2006]

Hi,

As far as I am aware all the test points are in there for the oxygen sensors,cam sensors etc and the TE1/E1. The port is just to the left of the oil filler car (looking from the front of the car) and is clearly marked "DIAGNOSTICS" on the top,if you carefully unclip the cover off all the pinouts are marked on the inside of the cover (clever Lexus thinking eh!).

I wished you lived nearer I would love the challenge of trying to sort it!

Cheers,

Steve

[steve2006]

Cheers TigerFish, that was really helpfull to see the same jumper in the same place as mine, also it is intresting to see the socket looking so bad as mine looks the same, guess it is some sort of waterproofing on the spades and not just muck :)

Yes it is grease,you find it everywhere on the electrical connections,Lexus quality!!!