Brake Switch / Lockup wiring

[Tonyd]

Guys,

Just putting the finishing touches to the first Cobra ready for the govt inspection in a couple of weeks and thought that I'd get it moving under its own steam.

Its got a 93 LS400 standard engine and auto box ( with an ECU configured with 34/28/22/16 plugs) and some time ago following a wiring diagram for a 90 and a 96 LS400 I wired in the brake light switch into pin 16 with a Green/White on plug, the 28 pin plug.

Well it now appears that this is the wrong location for this signal to cancel lockup and therefore the ecu doesnt activate any solenoids whatsover.

Can anyone tell me what pin on which plug I should put the brake light signal down to enable the ecu to recognise the brakes are on and its safe to engage gears and necessary to cancel lock up?

Cheers,

Tony

 

[Lambo]

location of green/white wire

Hi Tonyd, maybe this will help it's from the 1990_ 1995 ls400 manual it shows the wire in question going to pin 19 of plug b if you can identify from the attached drawing which is plug b you should be all good if you need more help just ask.

regards
Lambo

 

[Tonyd]

Hi Lamb,

Thanks for that it confirms other wiring diagrams I have for my second 1990 engine and box but it does not apply to my 1993 year model because the plug configuration has changed from rectangular with two rows of pins into much more squarish plugs with four rows of pins.

Moreover it appears that even within a model year the wiring colour changes although the plugs may stay the same..........An aquaintance has the same year engine, same ECU plugs but it now turns out has different colour wires to mine in different locations on identical plugs. I had been using a 93 official Lexus wiring diagram which matched his wiring pin out chart in which the pin numbers and the wiring colours all coincided,

I then use his wiring diagram, that matches to the Lexus diagram, to wire up my gearbox connections and even though the wiring colours match to my plugs and wires, the functions do not as the gearbox refuses to play ball.

It appears that I was far too confident in the wiring department leaving it to this late juncture to get the car mobile but having had such an easy time getting the engines to run a couple of years ago I just thought "hey I have the diagrams, I have the plugs, I have the pin out chart.....its just a couple of wires........"

So at the moment I'm looking for a 93 loom chart with both colours and plugs that coincide with my own.

I do have another plan to get the info but I'll use a different thread to facilitate a means to achieve my quest for knowledge.


Cheers,

Tony

 

[sideshow]

brake switch has nothing to do with the auto changing gears

u prob have some other wiring issues there
not sure whta u might have gotten wrong but if the ecu starts the enigne then the auto should atleast get some gears
u can also try to find the 2 solenoid wires and power them up seperately
one at a time and see if it gets gears
as long as the auto has the front and rear speed sensor connected it should change gears
maybe u forgot to plug the solenoid plug in
ive seen it done before
the solenoid wires get given 12volts by the ecu to select gears
so its not as if u forgot the 12vs for the 2 other solenoids as it should still run
try get error codes from it
but im guessing u dont have the check light connected

any 1uz ecu with a 34 38 22 26 pin config can have 4 or 5 diff diagrams
they bloody changed things every few years
way i figure it out is connect a diag scanner and measure the left over wires and trigger then carefully and see what the scanner says
but nothing on the 26 pin plug should effect the auto not selecting gears
the spd signal wire is a backup
so as long as u have sp2+ and sp2- connected it should in theory change gears unless u have very low oil or a stuffed tranny

 

[Tonyd]

Thanks for that sideshow.

My understanding is that the brake light feed into the ECU is a safety feature to make sure that you can't take the vehicle out of Park without a foot on the footbrake. It also enables the auto lock up to be disabled when brakes are applied to prevent gearbox damage.

The engine and box came unsplit as a complete unit with the ecu and engine/ gearbox loom complete so if the required wiring is in the engine/ gearbox loom it should be present. Its the interface with the body loom where things have gone pearshaped.

I'll check the solenoid action with a 12 volt feed just to make sure but we were assurred that the engines and boxes were good, and the engines which we have run up certainly are fine, so I presume the boxes are also OK.

I know what you mean re the scanner, my B in L is an electronics engineer so I may have to borrow his intellect and get him on the case. I'll just drink beer and watch him play with the wiring.

I'm also contacting Lexus technical help in the UK as we have the original VIN number of the vehicle the engine and box came out of. Hopefully they should know exactly what wiring diagram for this particular car I need and may even supply same for a small fee. They have already provided documentary evidence ( proof of engine age) that negates the govt requirement to use catalytic converters so heres hoping, but if anyone else has any ideas I'm all ears.

Cheers,

Tony

 

[Cobber]

Hi Tony,

Lambo's drawing indicates pin 19 but that is for the 26 pin plug not the 28 pin plug you have. You will need to get the correct dwgs for your ecu plug configuration.

 

[sideshow]

those drawings lambo are for yr most common 1uzs going round
most are those diagrams
ls400 or celsior
anyway i think the ecus are too dumb to do that brake switch no rev thingy
maybe u have the inhibitor inputs to the ecu wrong
like is said there are afew differences on that style of plugs u have
maybe yr inhibitor is tellign the ecu yr in reverse and yr in drive or something similar
anyway i might be wrong but having no solenoids working might not be ecu related surely if u have speed signals to the ecu it should select some sort of gear
u might have another problem
test s1 and s2 for 12vs when starting to take off

 

[Tonyd]

Cobber, yep I need the right diagram for my 93 plug configuration, unfortunately there seems to be a number of different wiring diagrams that use my plug configuration.

I have a complete wiring diagram for a 93 ( which is my year) with the correct plugs, but on close inspection the differences in wire colour coding going into each plug are many and varied..........

You've got to love the engineers that thought of the ruse to keep changing the wiring colour codes and pin placements etc......Still the Lexus version of Spocks three dimensional chess is what keeps sideshow in the money.....

Sideshow, thanks for the advice, the ecu is at present not allowing any gears to be selected whatsoever, even though the mechanical linkeage is selecting the gears the ECU is not operating any solenoids.

Hence moving the gearlever out of park into any gear has no effect. The car just sits there with the engine merrily idling away. Still at least I'm not using much petrol......

Sticking 12volts into the solenoids does get them to operate however and the oil level is correct.

The engine and box only have 56k miles on them so its doubtful whether the box is naff...........it seems to have been working very well just prior to it running under the back of the artic that caused its retirement to the breakers yard. ( We even have the invoice for the cars last service......that bill must have hurt as much as running under the truck))

Its a wiring fault no doubt , wrong signal going down wrong wire, I just have to chase to find out which one it is.

There's a call into Lexus tech support atm asking for the wiring diagram for the exact, particular donor cars Vin Number so as long as I get that within the next two weeks the govt inspection can go ahead.

Anyone with any further 1993 LS 400 34/28/22/16 plug pin outs I'd love to hear from you.

Alternatively re my other thread, anyone know how to access the ECU in our snotter LS 4000 which is the same year and may have the same wiring loom?

Cheers,

Tony

 

[Tonyd]

Just a quick update.

I now have three printouts from Lexus techi help all of which could be applicable to my car, so I have asked for the actual pin out to the individual ECU.

In the meantime I have had a bit of a play and...........Bloody hell I think I've cracked it.

I used a bit of intuitive thinking, ie a couple of beers, a multimeter and a bit of guesswork, and the bloody thing shot off down the drive.........I found out that the brakes may need a bit of bedding in.....spongy as a loofah....reverse is good too......

Right then, time for another thread........

" How do I get rubber acceleration marks from wide soft compound Toyo's on a block paved drive........preferably before the Mrs get home...."

Cheers,

Tony

 

[cribbj]

Just a quick update.

I now have three printouts from Lexus techi help all of which could be applicable to my car, so I have asked for the actual pin out to the individual ECU.

In the meantime I have had a bit of a play and...........Bloody hell I think I've cracked it.

I used a bit of intuitive thinking, ie a couple of beers, a multimeter and a bit of guesswork, and the bloody thing shot off down the drive.........I found out that the brakes may need a bit of bedding in.....spongy as a loofah....reverse is good too......

Right then, time for another thread........

" How do I get rubber acceleration marks from wide soft compound Toyo's on a block paved drive........preferably before the Mrs get home...."

Cheers,

Tony

Boggles the imagination. Tony you've missed your true calling as a comedy writer.

 

[twong]

wiring

Hi Cribbj, I am working on a supra/ v8 project and I am having some problems
with my body wiring.Have you finished your supra project?

 

[cribbj]

Sorry Twong, not even close.

Lots of ideas on paper, but haven't built the harness yet.

 

[twong]

Do you by chance have the pinouts for the smaller plugs thats next to the ecu plugs, trying to avoid having to destroy my harnesses to figure it out.

 

[Lambo]

Just a quick update.

I now have three printouts from Lexus techi help all of which could be applicable to my car, so I have asked for the actual pin out to the individual ECU.

In the meantime I have had a bit of a play and...........Bloody hell I think I've cracked it.

I used a bit of intuitive thinking, ie a couple of beers, a multimeter and a bit of guesswork, and the bloody thing shot off down the drive.........I found out that the brakes may need a bit of bedding in.....spongy as a loofah....reverse is good too......

Right then, time for another thread........



" How do I get rubber acceleration marks from wide soft compound Toyo's on a block paved drive........preferably before the Mrs get home...."

Cheers,

Tony

hi tonyd, so what was the fix to make it move forward, would you be able to share for all, what pin did the brake go to, or was it a case of removing the wooden beer crates from infront of the wheels after you drank the contents lol

Regards
Lambo

 

[Tonyd]

hi tonyd, so what was the fix to make it move forward, would you be able to share for all, what pin did the brake go to, or was it a case of removing the wooden beer crates from infront of the wheels after you drank the contents lol

Regards
Lambo

Hi Lambo,

Following my couple of hours of hard thinking and gratuitious use of multimeter batterage Lexus techy support got back to me to confirm what I founmd out by trial, error and sparks.........( ok no sparks actually)

What I found is as follows. This is true for a 1993 LS 400 made for UK spec between August 92 and October 94 using the ECU part number 89661-5960.

The correct Lexus wiring diagram is denoted as EWD 154F.....quote this number and it will give you a definitive wiring diagram for a Lexus LS 400 UK spec car built betwen 08/92 and 10/94

The correct classification of the four dark grey ECU plugs are

22 pin plug A
28 pin plug B
16 pin plug c
34 pin plug D


Note : a number of wiring diagrams on the net show different plug denotions with plug A having 34 pins, plug D 16 pins, and plug C 22 pins.........you can imagine the confusion this can create.

Check your plug codes are correct for your particular ECU part number.

Now the correct pin and colour wire connections are for my particular donor car are

Positive Feed from brake light switch to cancel lock up Plug B Pin 16 Green/ White.

Feed from ECU to earth via kickdown switch Plug B Pin 15 Green/ Yellow.

Positive feed from Power Button switch into ECU Plug B Pin 4 Light Blue/White.

Overdrive -: Normal position is 12 volt Positive feed into ECU Plug B Pin 6. To turn overdrive off you remove the 12v feed by diverting it to ground via the Overdrive Off warning light.


On a seperate note I checked the transmission oil cooler yesterday and despite going up and down the road outside my house a few times and the car having been idling for an hour or so it was as dry and cold as a witches tit .........So I backfilled the cooling system with half a litre of ATF and it didn't even show an increase on the dipstick level which previously was already showed full.....don't believe the dipstick, it lies.

Also found out why the brakes were spongy......the Servo was giaphram was leaking so thats now been removed, replaced and all's well stopping wise. ( Note to self do not ever buy any braking components from Ebay)

Cheers,

Tony







.





.

 

[Tonyd]

Success (almost)

Right guys a quick update following a recent inspection of the almost completed Cobra by Her Majesty's Vehicle Inspectorate.

Last Friday morning at 7.00 am ( it was also 4 degrees C and foggy here) I took the Cobra that had all of 2 miles on the clock to the local Birmingham testing station for Single Vehicle Approval.

It failed............on an incorrect dash radius and the wheels protruded outside the body plan if measured with a micrometer ( I kid you not it was measured with a digital vernier gauge).

The dash radius was down to the trimmer who didn't pad the bottom of the leather covered dash enough and the wheels were down to the fact that we had a stickler for detail (Or as the govt is replacing the SVA with Individual Vehicle Approval, they have no IVA tests booked for May so they were making retest jobs for themselves....In that out of 20 cars tested last week, not one car passed, the inspector proudly told me)

We were told by the inspector to go and pad the dash a bit more and to borrow any set of wheels with correct speed rated tyres on the retest which would be a 20 minute job and we could go and refit the original wheels the next day.

So all in all not a bad result. The dash has already been retrimmed, borrowed wheels sourced and fitted, so we are now waiting for a retest date.

Most importantly the Lexus engine box combo behaved absolutely faultlessly.

I was terrified that it was running a bit rich for the emissions test, even though because its a 93 engine we didn't need cats, and the inspectors body language when doing the emissions test was disconcerting. It was only when he gave me the printout from the machine CO 0.14 versus 3.5 limit and HC 214 versus a 1200 limit that I relaxed. He even ventured the opinion that the engine may be running a bit lean at the high end of the rev range so I'll be checking out /cleaning the injectors in the near future.

The test was over by lunchtime so we took the long road back home, me thawing out in the Lexus support vehicle, aka snotter, and Tim owner of the first almost legal 1UZFE powered Cobra in the UK taking the lead.

Given that the weight of the Cobra is 1038 kilos with a full fuel tank, and the weight was measured at the test, it should indeed go well with a 56k miler donor engine sans those cats.

I can now confirm that it goes like stink. I was expecting Tim to give it a bit of a blast so in the snotter I had the power button operated, Overdrive off and tried to keep up. Absolutely no chance whatsoever......:lmao::lmao::lmao::lmao:

Once home we cracked a few bottles of juice, as we do, to celebrate.

Cheers,

Tony

 

[Kurtis]

Tony can you please send me the wiring diagram you it won’t down load from your post bro you already know what i am going through my email [email protected]

 

[gloverman]

This might help too