Transmission Self Diagnostic = Cool!

[Mint Q45A]

Q45, 1994.In the last few months I started to notice that the shifting wasn't as crisp as it used to be. Sluggish, delayed, like it was slipping, specially from 3rd to 4th.

Over the weekend I thought about exchanging the AT fluid, but it was perfectly clean so decided not to - it was probably going to be a waste of money.

Today I decided to run the Self Diagnostic, as described in the Service Manual (Section AT-41). The result: #3 ; Throttle Position Sensor Circuit.

Based on this I unplugged the connector to the TPS (on the Throttle Body) and cleaned the contacts with a small file - they had a tiny bit of corrosion; then applied some di-electric grease and plugged the connector back. Ran the AT diagnostic again = OK!!Went for a drive and the shiffting is now perfect....

This might help somebody else experiencing similar symptoms with the AT...

[AlabamaDan]

Congrats and thanks for the tip. Did the self diag give you a code about a bad connection?

[Mint Q45A]

Yep. Code #3....

[Window45]

mine does the same? where did you find the info to do the self test?

[Q451990]

It's in the FSM (Factory Service Manual) in the "AT" section.

The manual is available for download at http://www.phatg20.net

Heath

[Mint Q45A]

Here are the instructions (but I strongly suggest you revise the manual)

-Start the engine and warm it up to normal operating temp- Turn the ignition to the OFF position- Move the selector lever to "D" position - Note: This requires using the Shift Lock manual release, next to the lever- Turn the trip reset button counter clockwise and hold it- Turn the ignition switch to "ON" but do not start the engine

At this point you should get a message on the dash saying "AT Testing" (or something similar...I don't recall exactly). You can then release the trip reset button...

- Move the selector lever to "3" (gear)- Depress the accelerator pedal completely and then release it- Move the selector lever to "2" - Move the selector lever to "1"- Depress the accelerator pedal completely and then release it

At this point you are done and need to wait for the testing results

After a few seconds you should see some sort of message: OK, or a number...(in my case it was #3). Each number indicates a different issue

The table with the issues by code are located on the same manual....on sections AT-42 and AT-43.....

Hope this helps.

[Window45]

works wonderful.. however i dunno how to unlock the shifter, their is that little thinggy that says "shift lock" but i don't have a key for it... what to do?

[Mint Q45A]

Very carefully remove the black plastic cover - you can use a small screwdriver to pry it

You will fiind a small phillips head screw - remove it. A second piece of plastic will come off. Now you have access to the button/lock.

You can use a flat head screwdriver to push on the button (is spring loaded), hold it down...now you can move the lever to "D"...

Hope this helps...

[Window45]

muahah, thanks, and just do that test, and it will give me a code, eh sounds good ill go try it

[TBrack]

I was able to do the diagnostic by just shifting to drive and turning the car off instead of using the shift lock

[goody90q45]

I was able to do the diagnostic by just shifting to drive and turning the car off instead of using the shift lock

You didn't follow the FSM? You're lucky your Q didn't sprout wings and fly back to the manufacturing plant when the odometer button was rotated. Who knows what hidden commands are really in the ECU.

[Mint Q45A]

Good to know...And did you get any codes? Or is everything ok?

[maxnix]

I was able to do the diagnostic by just shifting to drive and turning the car off instead of using the shift lock

Seems like the shift solenoids might end up in a different state with car in D as opposed to P. But if there is no power, it may not matter.

[TBrack]

yea I was just being lazy and didn't want to pop the shift lock up. I got an "OK" on the diagnostic.

[666-g50]

alright so my check says A and D,

turbine revolution sensor,what does that do?

[Infinitiguy19]

D I think is the battery:The battery power is low or has been disconnected for a long time.

The turbine sensors are a common problem, Check the transmission for leaks (check around the top of the bell housing or where the 4 switches meet near the drive shaft.)

[Mint Q45A]

Make sure the connector(s) to the Revolution Sensor are clean and ok...The A error means that the circuit is shorted or disconnected (open, dirty...)

[Window45]

i was able to do mine too, i got an ok i too wonder what sort of hidden commands these things have in the ecu, anyone know of any other self tests you can do,. i know if you leave the car in park, turn the knob clockwise instead of counter clock wise, then turn car to on and let go of the knob the little screen just has a little dance , well it looks like a dance to my gf anyways

[Infinitiguy19]

i was able to do mine too, i got an ok i too wonder what sort of hidden commands these things have in the ecu, anyone know of any other self tests you can do,. i know if you leave the car in park, turn the know clockwise instead of counter clock wise, then turn car to on and let go of the knob the little screen just has a little dance , well it looks like a dance to my gf anyways

That checks the screen basically to make sure that the bulbs work and the screen is functioning.

[goody90q45]

i was able to do mine too, i got an ok i too wonder what sort of hidden commands these things have in the ecu, anyone know of any other self tests you can do

The electrical section of the FSM should be renamed the Voodoo section. It's packed with a couple hundred pages of self diagnostic tests.

http://www.nicoclub.com/FSM/Q45/1995_Q45/1995_Q45/

.......i know if you leave the car in park, turn the knob clockwise instead of counter clock wise, then turn car to on and let go of the knob the little screen just has a little dance........

I made the same mistake but enjoyed watching the screen go through its paces for a few minutes.

[666-g50]

mint

are these connections visible from the engine bay or do i need to go underneath,recommended cleaner?

[Haitian_King]

One thing that the FSM failed to mention to me is that you need to make sure the parking brake is engaged, or that the car is on a flat surface. The first time I did the AT diagnostic, I was in my driveway. I forgot to set the parking brake and the car started rolling as soon as it was out of Park. Keep in mind with the engine off, your brakes are a bit useless. At least in my case.

Then again, no one else was probably as dumb as I was when I first got the car.

[Mint Q45A]

666....You need to get under the car....As per the FSM there are four different connectors, including one from the revolution sensor harness, located on the back of the transmission, just above the transmission/exhausts rubber support/mount.

Note: the one from the turbine sensor is located on the upper left (driver side)

If you have access to the Service Manual, look undet AT-35 (pag 391 on the version I have)

You can unplug the connectors and clean them thoroughly making sure all terminals are clean - an electronic parts cleaner may work, but make sure you remove the rubbery seals (located inside at the bottom of the plastic housing/connectors) before using the cleaner - otherwise these will swell

I would give it a try...that's what I did with the connector for the TPS


Modified by Mint Q45A at 7:39 PM 10/11/2008

[jmorasch]

Does the diagnostics show any other codes if the D code is displayed?? Do you know when the check is over with...the little square that blinks on every few seconds...that mean the systems still checking?? D is suppose to indicate theres a charge problem with the battery??? Ive had no problems with the battery. I noticed that from 2nd to third shift,the trans.seems to drag for a brief second and then shift.Its not too noticable but its there.

[goody90q45]

Try running the self-test a 2nd time (short drive between tests) and I think the battery code will go away.

[jmorasch]

THANKS goody,will do!!!