Cant get auto transmission in 89 GQ auto to go into diagnostic mode.

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Originally Posted by Alitis007

Have fun mate! I just remembered when i had my TPS. Fault every time i started the car the POWER button would flash but now it just stays illuminated for 2secs showing theres no code. Have you played with the TPS again after you got the converter sorted? Maybe the auto is thinking your accelerating harder then you are and its trying to kick down n go??

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TPS is fine, kick down works fine, power button works fine, just cant get into diagnostic mode

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Originally Posted by ckh

manual it say if the power light stay on and doesnt go though the test its either Inhibitor switch, power shift switch, kick down switch idle switch or the A/T controler is damaged.
1. Inhibitor switch must be working as I can only start the car when in park or neutral.
2. power shift switch is working as when triving if I hit the power switch, it drops down to 3rd, when I turn switch of it will go into 4th and then converter lockup if doing over 85
3 kick down switch is working as if I press accelerator hard it unlocks converter and kicks down a gear, or if driving slowly will drop down a gear, if going really slow and hit the pedal, it kicks down and the power light comes on.
4 idle switch dont know how to check this one
5. A/T controler is damaged. cant test this either as dont have a spare A/T controler at the moment but may be aquiring on in a few weeks.
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Originally Posted by ckh

TPS is fine, kick down works fine, power button works fine, just cant get into diagnostic mode

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Diagnostic mode is ment to tell you what's wrong with the auto box. By having the power light stay on its trying to tell you that one of the above things isn't right. So that's a diagnosis isn't it?
You're expecting it to show something different than what it's showing you?
Another thing that got mentioned to me is to clean the pins/plug on the tcu.(in the passenger foot well on the door side). It made no difference to me but worth a shot

FanTapstic!

anyone got any tips on fault finding the wiring looms, it has to be one of the a broken wire or something....

If it was a broken wire would the problem come and go (ie engage/disengage)? Or would it just never lock up?

FanTapstic!

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Originally Posted by taslucas

If it was a broken wire would the problem come and go (ie engage/disengage)? Or would it just never lock up?

FanTapstic!

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well there is something telling the computer to unlock every now and then or maybe the computer its self, the fact I cant get it into diagonostic mode since the guy dropped the box ans did the converter, any plugs or wires he had to disconnect to do that job could have got bent or broken

Yeah that's what I mean, there's something making it unlock but if it was a broken wire it would probably be a constant thing. Not saying it's not a broken wire, just that it's more likely something else.
As I've said above, my diagnostic thing was doing the exact same as yours.
I wouldn't be too concerned with "getting it into diagnostic mode". I think it is diagnosing the problem as the books clearly state that a continuous light means those things you've mentioned above. Isn't that the diagnosis??
Anyway I would start checking all of the suggestions people have made.
TPS
Fuses
Loose or dirty plugs
Faulty power/overdrive button
Tcu plug condition
Fluid condition, type and level
TC condition
Temp sensors
Speed sensor




FanTapstic!

The temp sensor may have been incorrectly fitted or damaged when the box was out

FanTapstic!

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Originally Posted by taslucas

The temp sensor may have been incorrectly fitted or damaged when the box was out

FanTapstic!

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he shouldnt have needed to touch it

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Originally Posted by taslucas

Yeah that's what I mean, there's something making it unlock but if it was a broken wire it would probably be a constant thing. Not saying it's not a broken wire, just that it's more likely something else.
As I've said above, my diagnostic thing was doing the exact same as yours.
I wouldn't be too concerned with "getting it into diagnostic mode". I think it is diagnosing the problem as the books clearly state that a continuous light means those things you've mentioned above. Isn't that the diagnosis??
Anyway I would start checking all of the suggestions people have made.
TPS
Fuses
Loose or dirty plugs
Faulty power/overdrive button
Tcu plug condition
Fluid condition, type and level
TC condition
Temp sensors
Speed sensor




FanTapstic!

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I wouldn't be too concerned with "getting it into diagnostic mode". I think it is diagnosing the problem as the books clearly state that a continuous light means those things you've mentioned above. Isn't that the diagnosis??
Anyway I would start checking all of the suggestions people have made.
TPS
getting a second hand tps this sundat will try it..
Fuses
can only find one fuse related to A/T in fuse box near drivers kick panel
Loose or dirty plugs

have unplugged the connectors near the battery and cleaned them with contact cleaner, and even a "nipple cleaner" for a gas cutter to make sure contacts were clean, can you tell me the location of "all" the plugs they would have had to undo to drop the tranny out.... Am also getting a second hand wiring loom and computer for it along with a spare transmission this sunday so will have bits and pieces to swap around, I agree bad or dirty plugs/contacts as appart from lockup everytyhing worked and tested fine before they changed the converter, Put 12V to the lockup wire yesterday and it locked and stayed locked until I turned switch off, so want to find whats telling the computer to unlock for that befif period.
Faulty power/overdrive button

It works perfectly, press it, power light comes on and it drops down gears, turn on get 4th back
Tcu plug condition

cleaned the conects and plugs on it yesterday after doing the 12V test and soldering it up when finished
Fluid condition, type and level

The tranny guy says it the correct specified fluid and levels are correct
TC condition
New, and by running 12V straight to the solinoid and bypassing all other electricals that come into ply, locks up and stays locked
Temp sensors

Found a thread to wire a resistor in place so the TCU thinks the tranny is always are right temp regardless if temp sender is faulty or not...
Speed sensor

Dont know how to test speed sensor... but as said earlier everthing was fine until he dropped the tranny out, so leaning towards either a dirty or not fully connected plug, or if one of his apprentices did it, maybe there was a plug he forgot to unplug when starting to drop tranny ut and resulted in stretching or breaking a wire..

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Originally Posted by ckh

he shouldnt have needed to touch it

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Doing the trick with the resistor will get around the temp sender if there is a problem there and may cure my unlocking issue, but i want to solve WHY I cant get into diagnostic mode and what the problem is there...