"o/d off" Keeps flashing on dash

[Z2TT]

Hi,

1989 Soarer GZ20 Automatic

This is the situation :

I always have O/D turned on, and at random times the O/D off switch on the dash would begin flashing at a constant rate while driving, and the car drives so bad aswell.

Ussually if overdrive is off, if I switch it off using the switch on my paddle, the "o/d off" light would remain lit.

But I dont understand what it means when the "o/d off" light is FLASHING, even when o/d is ON.

Why at random times would the "o/d off" light begin to FLASH, is it some kind of error report with the transmission computer or something?

Any Ideas?

Thanks.

[RA35GT]

Dood thats the "check engine" light but for the auto transmission. (I.e. the auto computer is not happy).

(Due to the way the light is wired up, it can only flash the light when O/D is on).

Some info here dood. http://www.cygnusx1.net/Supra/Librar....aspx?S=AT&P=7

[Z2TT]

Thanks for that.

I read here :

http://www.cygnusx1.net/Supra/Librar...aspx?S=AT&P=14

The thing I don't get is :

"Using SST, connect terminals T and E of check connector"

Are these some types of contacts that are located under the small box that says "Diagnostic" on it?

If so what is it that I must do?

[RA35GT]

Yeah mate, they are in the diagnostic box. open the lid and there should be a label for which terminal is which.

Just get some wire (or a paper clip is easier) and join the two terminals together. Then follow the instructions in the manual.

[Z2TT]

Ok I just spent a while trying to get it to flash.

I followed the instructions on the manual correctly, but i could never get the light to flash, It should be flashing (once every second) even if there is no errors according to the manual, but it does not flash at all. I used a wire to bridge the 2 connectors and made sure it had good contact, but still nothing.

I am sure that the wire is not corroded, and is making good contact because I tried to bridge other terminals and I was able to get the TEMS lights flashing on and off, but I was never able to get the O/D off switch to flash by joining terminals Tt and E1, I tried about 10 times double checking everything, but it does not flash.

[wilbo666]

You need overdrive on to make the light flash, did you have the overdrive button on?!

Cheers
Wilbo

[Z2TT]

No, I left overdrive ON, as per manuals instructions.

http://www.cygnusx1.net/Supra/Librar...aspx?S=AT&P=14

"1. Turn ignition switch and o/d switch to ON"

[wilbo666]

Haha, yah that's what I meant (got it arse about) .

And the light does come on when you turn overdrive off? (i.e. the bulb isn't blown...)

Cheers
Wilbo

[Z2TT]

Yes it does, Heh if the bulb were blown it would have never began flashing while i was driving in the first place

So nope thats not the case, the light works.

[wilbo666]

Yep, just wasn't sure if you had checked to make sure the OD light still worked since you started to pull codes

It might be an idea to check the Tt pin in the diag box has continuity to the ECU...not sure if the GZ20 has a separate Auto ECU or not...

Cheers
Wilbo

[Luke20t]

is the light on when the car is started? if not it may be an intermittent fault, take the car for a drive, wait for the light to come on, bridge the diagnostic connector with out turning the car off and see what happens.

Also bridge te1 to e1 in the normal way, to see if any engine codes are stored.
(I also wouldn't mind betting that this is related to a speed sensor problem)

[Z2TT]

wilbo666 what do you mean by continuity to the ECU? I think the GZ20 has a separate automatic ECU as did all 1g-gte with a340e's didnt they?

Taken from 1g tech thread : http://www.toymods.net/forums/showthread.php?t=10548

Gearbox ECU:
(Electronic Transmission Control)
1G-GTEU Toyota (Aisin) 89530-24270 (ink stamp: 7F26 - serial number or ROM version?)
connectors: 24pin

Luke20t the light does not flash when I start the car, But sometimes while I drive it the light will just begin flashing, this usually happens once every 3 days while i am driving the light will just begin flashing, but does not happen on every drive.

But the error code should still be stored, and like the manual says even if there is no errors stored the light should still flash, but continuously once per second when the terminals are bridged - This does not happen when I bridge the terminals.

[Z2TT]

Luke I bridged te1 and e1 and now BOTH CHECK ENGINE and OD/OFF lights are flashing?
Why is the o/d off light flashing? shouldn't only the check engine light be flashing?

There spitting out heaps of codes

[Luke20t]

Luke I bridged te1 and e1 and now BOTH CHECK ENGINE and OD/OFF lights are flashing?
Why is the o/d off light flashing? shouldn't only the check engine light be flashing?

There spitting out heaps of codes

I think you will find that the auto ecu and engine ecu are one unit.
what codes have been stored?

[Aphox]

Have the codes built up? You should be able to reset the error code status and wait for the flashing light to occur again to read that?