Toyota Supra mk4 OBD1

Hi

can anyone tell me what the OBD1 DLC connector looks like on the mk4?

It's the service connector you connect a scan tool or a computer to.

A picture would be nice, especially with the cover pulled open.

I'm assuming it will have TE1 TE2 E1 W VF1 VF2 Ox1 B+ connections.

Thanks.

hmmm.

i'm not 100% but i'm sure this has been discussed before with the result being you can't use a uk scan tool or computer to diagnose imports.

*goes to search*

hmmm.

 

i'm not 100% but i'm sure this has been discussed before with the result being you can't use a uk scan tool or computer to diagnose imports.

 

*goes to search*

That's a shame. On the mk2 MR2 the OBD1 seems to be compatible on the UK NA mk2 (post 1991) and it also works on the JDM 3SGTE turbo import. Also works on the later UK ECU 1997+.

So I was hoping it would work on the Supra mk4 for UK + imported models.

you can use a bent paperclip, there is a thread somewhere, ill have a search and post the link

you can use a bent paperclip, there is a thread somewhere, ill have a search and post the link

There's also some real time vehicle data that can be read out of OBD1 connectors using a scan tool or laptop.

eg rpm, EFI, ign timing, throttle, o2 sensor, fuel trim etc.

Just wondered if the UK/import Supra4 had this data stream as well.

Isn't this the round plug under the dashboard?

Hi

can anyone tell me what the OBD1 DLC connector looks like on the mk4?

 

It's the service connector you connect a scan tool or a computer to.

 

A picture would be nice, especially with the cover pulled open.

I'm assuming it will have TE1 TE2 E1 W VF1 VF2 Ox1 B+ connections.

 

Thanks.

Go to your local Toyota dealer and ask them.

Go to your local Toyota dealer and ask them.

My nearest Toyota dealer is 12 miles away and they get twitchy if you ask about scan tools or anything to do with the ECU.

My nearest Toyota dealer is 12 miles away and they get twitchy if you ask about scan tools or anything to do with the ECU.

IIRC Tectom is the only way to capture streams from the "JZGTE ECU, i think Toyota's expensive equipment only monitors whats available via the diagnostic port which isnt much to be honest. Best thing to do is check the wiring diagrams and trace the non complient port on the later supras back to see which data channels it actually interfaces with..my bet is the usuall Ox1 and Ox2 as well as iGF. but its something ive never looked at. I guess the only thing people are interested in, is the Stock Ignition and fuel maps - again a TecTom thing?

IIRC Tectom is the only way to capture streams from the "JZGTE ECU, i think Toyota's expensive equipment only monitors whats available via the diagnostic port which isnt much to be honest. Best thing to do is check the wiring diagrams and trace the non complient port on the later supras back to see which data channels it actually interfaces with..my bet is the usuall Ox1 and Ox2 as well as iGF. but its something ive never looked at. I guess the only thing people are interested in, is the Stock Ignition and fuel maps - again a TecTom thing?

You can't get the fuel/ignition maps out with the OBD1 but you can monitor rpm efi ign timing etc. I worked out how to decode the OBD1 data and put it on a laptop.

You get:

EFI duration

Ign Timing

Throttle Pos

ISC idle valve Pos

Speed in mph

Coolant temp

AFM (MAP)

Closed Loop On/Off indicator

EFI fuel trim (short term learning)

O2 sensor status

IDL switch

STA (starter signal) status

and a few others.

Also a mpg display if you do some number crunching with the EFI/rpm/mph

So I'm trying to find out which Toyota models have OBD1 as the data seems to have a consistent format across all the various MR2 ECUs both UK and import. Maybe it's the same on most Toyotas.

This display is fairly basic but it would prove useful for faultfinding especially if the car has problems with mpg.

Chris wilson was looking into the Obd1 port data on the vvti IIRC, he also bought a new "device" tro try. Maybe worth contacting him..

I thought VVTI was OBD2.

Does the Supra connector look like any of these?

http://alexserp.nm.ru/Vista/poleznosti/Connectors1.jpg

Indeed it does... both right hand side ones..

I thought VVTI was OBD2.

VVTI is obd2, that is correct.

Indeed it does... both right hand side ones..

So some are DLC 1 (rectangular) and some are DLC 2 (round) ?

I was hoping it would be the one in the bottom left or maybe it would be DLC 1 at the top.

No1 in the engine bay, No2 under the dashboard.

No1 in the engine bay, No2 under the dashboard.

That's interesting. I wonder if the mk2 MR2 has a round one under the dash as well?

I've just designed a connector for the DLC1 type in the engine bay

This needs a 3 metre cable for the MR2 if you want to sit/use the laptop in the passenger seat as the DLC1 connector is at the back of the engine bay near the boot.

If I can make a generic cable that only has to be 1 metre long then that would be great.

Both right ones for me too.

That's interesting. I wonder if the mk2 MR2 has a round one under the dash as well?

If it does I never found it

Just spotted a problem with the round connector.

It doesn't seem to have a connection to the 02 sensor so this function on the display would be lost with this connector.

So I guess it's back to the square one and the long cable.