Help! At Light Suddenly Comes On When Driving

[Guest]

When I start my car up AT light goes on and then off straight away....

Whilst driving for about 10 - 15mins AT light comes on, gears jam up and as i put my foot on accelerator revs go up, but i dont go anywhere maybe like 20 kms at most.

I then turn the car off and start it again AT light goes on and off straight away, car changes gear but it still doesnt feel quite right. The same thing has happened twice now, i am taking the car to my mechanics tomorrow to have a look, he said he has never heard of the problem and thinks it may be an electrical problem and will have a look at the computer.

Has anyone heard of something like this? Im pretty worried.

I recently had the car serviced as well as a transmission service too.

But i havent driven the car in the last week which did cause the battery to die, i recharged it and the car started, but would the battery dying affect the transmission?

Thanks

[GTSBoy]

Don't let your mechanic waste any time looking for the transmission computer. If he doesn't know where to find it, he can't help you. Hint. It's in the ECU.

[Moodles2]

Check out MV Automatics, best place to get jap autoboxes looked at.

I would be suspecting the transmission service, what fluid did they use, was it Genuine Nissan fluid or wasn't genuine, if it wasn't genuine did it conform to the correct fluid that autobox requires (Matic-D, Matic-J etc)

[Guest]

ok. on Wednesday I drove it up to my mechanics in the morning, nothing was wrong, no AT light...perfect drive.

My mechanic calls me up during the day, says the car is running perfectly, he took it for a drive, says it was good. He said that he'll keep it overnight, and have another look, and drive tomorrow....all good nothing happened.

I then get it back and drive it home, I thought that was it.

I just drove it, the problem is back. I had to stop and start my car 3 times to get back home. Im getting sick of this, I cant even drive my car.. What could be the problem?

I think its an electrical fault somewhere it has to be.

If u can imagine me starting the car, drive it down the road...then all of a sudden AT light comes on, gear changes and the car wont accelerate....WTF?

*If i put it in tiptronic after the AT light comes on, it is in 4th and wont change, till i stop and turn off the car.

***when my mechanic had it, the only error code that came up was something to do with air flow, but that didnt seem to be a problem he said, as he took it for drives and said it was running great...he said that it would most likely be a faulty sensor, and not to be affiliated with the A/T problem

Edited March 10, 2012 by Jα©òβ

[kosmo90]

Sounds like it happens more when it gets up to operating temperature????

Can you borrow an ecu off someone?

[Guest]

Sounds like it happens more when it gets up to operating temperature????

Can you borrow an ecu off someone?

no i dont know anyone with an ecu

its so unpredictable....it happens just like that.

[GTSBoy]

If your mechanic is using a generic fault code scanner and it is returning code 070 (with a description that says INT/VOL or something similar) then it is not correct, and is in fact a fault from the traction control system. Alternatively, it could be a TCU fault. I have seen this happen on an R34 ECU using a generic scanner, but when you connect a Nistune laptop to it and look, it comes up as the correct fault (for the car I was looking at) where the traction control throttle motor switch was not being triggered. Anyway, the lesson here is that the generic code scanner could be telling lies.

[Guest]

been looking on other forums and stuff and it appears that people that have had the same or similar problem, have performed an auto diagnostic test:

R34 GTT Tiptronic Self Diagnostic

1. Warm engine.

2. Turn ignition on-off more than once and then leave OFF.

3. Turn ignition ON with selector in "P" position and ensure A/T warning lamp is ON for 2 seconds.

4. Turn ignition OFF.

5. Depress brake pedal and move selector to "D" position.

6. Turn ignition ON.

7. Release brake pedal and move selector to "3" position.

8. Depress brake pedal with left foot and depress accelerator pedal fully down with right foot and move selector to "2" position.

9. Read A/T warning lamp flashes for codes.

R34 Tiptronic Codes

After a long initial 'start' flash, the A/T lamp will flash through it's full code sequence (RB20DE 10 flashes or Non RB20DE 13 flashes), but any faults will be shown by a longer flash on the relevant code number. This sequence will then be repeated until you turn the ignition OFF.

1. Vehicle speed sensor 1

2. Vehicle speed sensor 2

3. Throttle postion sensor

4. Shift solenoid A

5. Shift solenoid B

6. Overrun clutch solenoid

7. Lock-up solenoid

8. A/T fluid temp. sensor, TCM power suply or throttle position sensor power supply

9. Engine speed signal

10. RB20DE Line Pressure Solenoid or Non-RB20DE Turbine Sensor

11. Non-RB20DE Line Pressure solenoid

12. Non-RB20DE Total control signal

13. Non-RB20DE Shift control unit

No flashes:- PNP idle switch/full switch or RB20DE Overdrive control switch or Non-RB20DE Stop lamp switch

A lot of the forums have said that it is probably a faulty solenoid, or something to do with the solenoid. Does anyone know if this is expensive to fix? Is it a big job?

As the car is really not drivable without me stopping every 10mins, I wold rather someone to come out and fix the issue, is there anyone in Adelaide that specializes in transmissions and is able to come out?

[Moodles2]

As I said before, MV Automatics, they are in SA and if I had any auto box problems I couldn't diagnose/fix I would be taking it to them.

[Guest]

yeah might have to do that.

btw i took the car for a half hour drive during the day yesterday not a problem....it might sound very weird and stupid, but the problem has only occurred whilst driving at night.

[daineisdabomb]

my gfs does the same thing. and its also intermittant. hers may drive fine for weeks and then it goes into a/t mode. have u run the gearbox diagnostic test and written down the fault code/codes? if so which codes have come up? urs sounds like an easy fix because it is happening so frequently. check the codes n see what it says. another thing if the throttle position senson stuffs up it triggers a/t mode which sounds like ur problem. to check it u need to check the correct pin on ur tcm/ecm with a volt meter and it should read .5 volt with throttle closed. if it reads 5v then its stuffed but u will need to check it as soon as the a/t light goes on. let us no how u go.

[rs44me]

My car has just started to throw the a/t light at me in my gtt. It has only happened twice both times on the freeway with cruise on and 1500km apart . Did you guys have any luck? Im going to change the fluids in the next week or am i wasting time and money. anyone know of a good auto center on the central coast nsw.

[GTSBoy]

You do know that the TCU retains fault codes in the same way that the ECU (as if they were different things on an R34 anyway!!) does, and that any 6 toed moron with a scan tool can pul the codes out and tell you what is wrong with it, don't you?

[dumpit]

my stagea started doing that when we removed the battery while waiting for new turbo to arrive. A week later once new turbo was installed driving to get nistune and on the way it just stopped, no acceleration and unable to steer.

Has only now happened for a couple of days but since then has not come back. This issue happened with stock computer and with new computer with nistune board.

[xntrq]

This happened to me before driving down the hume HWY @ 110 KM/PH. pulled over and restarted and was fine. never happened again.