Ecu Pin Out (1 Viewer)

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Joined
May 3, 2006
Threads
36
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445
Location
Ontario
The ECU on my LJ78 2L-TE is 175800-1070-12volt.
Dose anyone have a pin out pic of this ECU that can be posted??


Thanks
 
Just a bump.
 
Lj78 Twh Sensor

Is there any one out there that knows which pins on the LJ78 ECU
(PART NUMBER 175800-1070-12volt)
connect to the THW Sensor.. And colour code of both wires?

I know it is on plug 26P but need to get verification on pin out and wire colours.

Can any LJ78 Lovers help me with this .. assistance greatly appreciated.

Regards
 
OK Wayne, suck at electrics or not your the only one to offer, buddy.

What I need to know is ---
The colour of BOTH the wires from the water temperature sensor (THW SENSOR) located to the rear of the block on a prodo 2L-TE under the intake manifold behind vsv's.
IT is classed as hidden sensor 1 of 5 on the 2L-TE. Is a PITA to get to on the motor with out some sort of tear down.
Once I know the colour of the leads plugging into this sensor I can locate them at the ECU. ( 10 minute job) Then I can test it to see if it is screwed.
It is about the only sensor on this truck I can not get to to test. ANd is probably the bad one.

The other thing that would help is a labelled pinout diagram of the ECU for this truck.(LJ 78) It will show where the THW sensor plugs in.
If I had that I wouldn't need the wire colours
I just happen to have the number 175800-1070-12Volt.

Any help here would be appreciated.



Rich
 
Rich, you may have better luck over at www.toyotadiesel.com. There are lots of people on there who've swapped 2L-TEs out of JDM Hilux half-cuts into their minitrucks, and most of those folks will have dealt with wiring issues. You might want to start with a search and then follow it up with a question if need be.

As far as I know, there's no English-language shop manual for the LJ78, which is why you're prolly not getting much response to your question. You're in uncharted waters, my friend.

Robin
 
both my LJ78s are sitting at the acreage and it is raining
BUT
if you don't have an answer in a couple days i can go take a peek for yah...
OK Wayne, suck at electrics or not your the only one to offer, buddy.

What I need to know is ---
The colour of BOTH the wires from the water temperature sensor (THW SENSOR) located to the rear of the block on a prodo 2L-TE under the intake manifold behind vsv's.
IT is classed as hidden sensor 1 of 5 on the 2L-TE. Is a PITA to get to on the motor with out some sort of tear down.
Once I know the colour of the leads plugging into this sensor I can locate them at the ECU. ( 10 minute job) Then I can test it to see if it is screwed.
It is about the only sensor on this truck I can not get to to test. ANd is probably the bad one.

The other thing that would help is a labelled pinout diagram of the ECU for this truck.(LJ 78) It will show where the THW sensor plugs in.
If I had that I wouldn't need the wire colours
I just happen to have the number 175800-1070-12Volt.

Any help here would be appreciated.



Rich
 
Thanks for the responce Robin.

EDIT} Robin thanks for the wiring diagrams. They should be very handy.
I'll print them out put them to geather and see what I can find.


I have posted the question on all the major Toyota boards.

All I can do is check them now to see if any one has the info.
Actually.
All I really want to know is which pins or the colour code on an LJ78 ECU feed the THW sensor.
If I can get that I'm golded .

EDIT } What I am finding is different coloured wires to the THW sensor . I have to verify these colours on AN LJ78 Prado.
SO Wayne if you have an easy way to check the colour code of the THW sensor plug PLEASE do.....


The reason I posted the question is that the Sensor is a pita to get to without disembling part of the motor in some way.

I just figured some one would have done a sensor repair and know what these two wires colour code is on a Prado.
In my serching I'm finding there is more than one 12 volt toyota ecu in the cruisers. So one has to be sure of the info.

It would be great If some one with a PRADO has the info.
I know there are lots of them out there..

Nice to hear from you again Robin.
Cheers my friend..

EDIT} Thanks again guys.

Regards
 
Last edited:
More Info Off My Ecu

Ok was out in the dash after work.
Here is my ECU PART NUMBER 89661- 60111 this was hard to read.
Also the ECU is labeled 2L-TE A/T
PLUGS are 26 16 and 12
and again these numbers under the part num. 175800-1070-12volt.

Robin your diagrams has been a great helped but the colours coding is different on my pin 3 and 16 so still confused and need confirmation of THW sensor plug wire colours on a Prado.
There are I'm finding more ECU's for the 2L-te than I thought.

Thanks again for the help.

Regards
 
Last edited:
On the Prado, at least, the temp sensor is not that hard to get to. you have to move the fuel filter out of the way, then remove some of the EGR plumbing (I think crushers posted some info on EGR a while back - have a look at it) to access the sensor.

There are temp vs resistance tables available for this sensor in other Toyota manuals, since it's a commonly used sensor. Compare the heat of the block (with an IR thermometer) and the value the sensor provides.

This sensor is one of the more important ones for regulating fuel delivery.

hth.
John
 
OK
I had tested the sensor from the wire harness plugged into the ECU.
and found that as the sensor was cold it went out of spec. there for hard starts on cold morings and espesially in the winter. As it was heated and up to running temp went within spec..

I just wanted to verify things before I cut into the wire harness..
We I received some info from all the major boards on the internet as I tried to ask the same question on each.

Mainly pin out and colour code of the wires feeding the sensor..

Well last night I pulled the battery leads off the battery, pulled the 26 pin plug out of the ECU got hold of that pesky (red and White wire in my truck) THW sensor feed wire ...I then proceeded to cut it. That's right I cut it stripped and tinned the ends. My wire harness is no longer virgin..
I then wired in a variable resistor, mounted the knob in the dash..

Results -- Fixed my cold start issue. dial in high resistance for first start of day.. tells the ECU to fuel more and away I go. As It warms up dial out the extra resistance.

As long as there is continuity in the sensor this can be applied.
If the sensor is open this will not work.

Thanks to all that gave me some badly needed help.
This has been a persistant problem for me since last winter.
Tried a lot of things..Tested just about every testable sensor on the truck & the best thing of all Learned so much along the way.

Regards
 
Last edited:
OK


Results -- Fixed my cold start issue. dial in high resistance for first start of day.. tells the ECU to fuel more and away I go. As It warms up dial out the extra resistance.

As long as there is continuity in the sensor this can be applied.
If the sensor is open this will not work.

Thanks to all that gave me some badly needed help.
This has been a persistant problem for me since last winter.
Tried a lot of things..Tested just about every testable sensor on the truck & the best thing of all Learned so much along the way.

Regards

congrates...
 
I have been following along the thread. I have a similiar problem but is sorted out by heating the feul pump right around the RPM senser connection. That is the plastic lead that sticks staight up on the top of the feul pump.

My query here is that the RPM sensor is not a temp senser but is proven temperture related problem that I fix by heating that specific part. Do you know if the senser you bypassed feeds that senser? Which makes the RPM sensor term wrong. It's an output of some kind . that works for proper feul feed.

Could you give an accurate description and placement of that part? I pict if possible.

Thanks
Fellow Prado Lover
 
Hey Prado-kirk
All I can tell you is my experience.
The THW sensor was my issue.
This was figured out by procces of elimination over months of testing sensors etc..
I tested this sensor and it showed shorted with next to no movement on the ohm meter as the motor heated up. Cold the resistance should be high and hot it should be low.
This sensor is connected into the ECU and as the THW sensor changes resistance different signals are sent to the fuel pump by the ECU. So for example when it is cold out it tells the ECU it is cold and the ECU in turn tells the fuel pump to fuel more on start up. AS the THW sensor warms the resistance changes and that tells the ECU to fuel less. This is critical on a cold start. If the THW sensor is not functioning then the fuel pump may not pump enough fuel to start the engine. Which is where I was when my troubles started.
The truck became very hard to start. Almost impossible to get going.
SO since the sensor is shorted like no resistance it tells the ECU not to fuel enough on a cold start.
Since this is a hidden sensor on the 2lte I went after the pin out on the ECU to determine if it was good or not. That is why I was after the pin out of the ECU.
In the end I wired in a veriable resistor that I control.. ON a cold start I just dial in the area it needs to be in to tell the ECU to Tell the fuel pump to fuel more.
On a hot day I just leave it alone.. You can only do this as long as the sensor is shorted out.. If open is like a really high resistace that would possibly tell the fuel pump to pump too much fuel or be out side the range the ECU needs to read it properly on a cold day.
Once I knew the problem and how to fix it sort of, away I went.
It was -21 this morning and she started on the second crank I just dialed in the resistance pushed the wilson switch and away I went.. I should note here that the air sensor in the air intake also figures into the equasion and what it senses also goes the the ECU. I never went after as it was not the problem for me.
The THW sensor here is 260.00$$ labour to change it was never disclosed to me so I have to figure it was a lot of $$.
Cost of variable resistor was $0.25 Time to install in dash board 0.5 hours..
Just have to know what your doing as your into the ECU harness..
I 'm putting a disclaimer on this long blurb as I want no one blaming OR flaming me for screwing up thier truck.
As I said at the begining My experience.

As far as the sensor? you are heating up. What are you heating it with??
You need to determine if it is a sensor of some kind then figure out how it works then you can figure out your next step. To be honest I have not looked at my fuel pump lately.. And probably won't till next service.
If you are sure that is your issue perhaps try and get a part number for it then re search that to find out exactly what it dose and what tells it to do it.
That would put you in a better position to rectify the problem and understand what is going on. Thats the big thing what is going on.. Try for a wiring diagram
it may point you in the right direction.

Hope this helps you some what. I know it can be frustrating..very frustrating.


Regards
 
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Thanks for the response.

I heat that senser on top of the feul pump that sticks straight up with a gallon of warm water poured over it. It's a pain but it gets me going. It also pains me that I'm pouring water over electrical connections.
It a real temperture sensitive problem. If the whole engine bay cools to 3 to 8 C then it won't start. Its starving for feul.
I have been looking at diagrams but they don't help if I can't determine their location. I need to find out what those other sensers are on the pump itself.
My search continues.
 
Yes Rummat81..
Thanks so much I have it already printed out.. err ah... long ago..
Tells the pin outs.
I finally just used that pin out to locate wires in the harnes.
I'm still using this set up -- It reminds me of a choke from the old days..

Regards
 
And this sensor i believe is not hidden,
it is the left most sensor on the thermostat housing, while looking from the front towards the engine. It has 2 wires going to it.

The EPC lists this sensor for the ECU at this locations as well.
I tested myself with resistance present when the sensor was plugged in and not plugged in.

hope that helps.
Ali C.
 
The sensor is on the block above and sorta behind the starter.
It is not the one on the thermostate housing.

That would have been an easy fix.

I have already fixed my problem ages ago,, check the posts.:hmm:
 

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