Intermittent Fault With Auto Gearbox

[kenneth]

I recently took over the ownership of a 97 Fiat Brava 1.6 ELX. It has clocked 90,000 km. The car runs well except for:

1)A problem with the automatic gearbox
2) Engine seems to hesitate a little when revving from cold start

Auto Gearbox problem
--------------------
Its gearbox indicator light will flash to indicate a fault when I attempt to drive off after starting the car in the morning ? I will then have to turn off the engine and restart the car, and after a number of attempts, the fault would clear, and I would be able to drive it without any problems. What could be the cause of this ?

I have sent the car to a local Fiat authorised garage, they interrogated the gearbox ECU with the Fiat Examiner which reported:

- A hard" on "lock solenoid open circuit or short circuit to +" failure.
- Soft "incorrect gear lever position" error

My questions (and I hope someone out there can shed some light in this matter):

1) Has anyone out there encountered a similar fault condition before ?
2) How can I physically check the condition of the lock solenoid (the Haynes manual does not come with an electrical diagram for the Aisin gearbox) to confirm the problem ?
3) Is it an easy repair job to access and replace the lock solenoid ?
4) Could the gear lever position sensor be intermittently failing ? How can I confirm this ? Is this a common failing item for a car of this age ?
5) Does the lock solenoid and gear lever position sensor (Aisin gearbox)have common parts with other makes of Japanese cars (Toyota, Nissan, etc.)?

I have the external wiring and connections leading to the gearbox and they seem to be OK.

Engine hesitating problem
-------------------------
Examiner interrogation of engine ECU gave:

- Soft intermittent error for lambda sensor
- Soft engine operating parameters out of range

Any advice or responses is much appreciated and eagerly awaited.


Great forum !!!

Regards,
Kenneth
Malaysian Fiat owner (small Fiat community)

 

[Chris]

Aisan

Nice to see you have so much technical detail. You don't say whether the box is really in trouble or whether it's just the warning lights.
The box is used in Vauxhall/Opel mainly Astra and Vectra. It's not unusual for the Fiat dealers not to know the details as it's such low volume for them. I believe that they bought the whole installation from Aisan. Your best hope is an Auto G/Box specialist. My own experience is that many of the ECU faults are related to the connection blocks. The extra resistance is enough for clever ECUs to pick up an out of tolerance reading. Pull all the plugs and give them a firm push home.
On the misfire I would start with the Lambda sensor. Its life will be over at this mileage and the 60 uk Ponds cost is well worth it.

 

[kenneth]

Intermittent Gearbox Failure

Chris,

Thank you for responding.

I doubt it is the indicator light which is giving the problem, more of the gearbox or the gearbox's electrics itself. Once the car warms up during the drive, I have no problems with the gearbox (i.e. the warning light no longer comes on) for the rest of the journey. Strange huh ?

As for the Lambda sensor, if 90k km is beyond the live expectancy of the sensor, I will have it changed then.


Regards,
Kenneth

 

[Chris]

I didn't make myself clear..

I was asking whether you really have a fault with the gearbox (ie something not working) or is it just a warning light on (ie the box is normal but you have a warning light for the first part of the journey).
If it is the latter, remove all the connector blocks and dry them out and then reseat them.

 

[kenneth]

Allow Me to Clarify

Hello Chris,

My apologies if I did not make myself clear in earlier appends. Let me try putting things right....

I only have the gearbox light flashing when I attempt to start the car from cold (eg. in the morning) and I attempt to engage gear. Once the light comes on, I will have difficulty selecting gears, I need to restart the car, and after one or a few attempts at starting and engaging, the problem will clear and I will have no problems (no gearbox flashing light or difficulty in engaging gears) for the rest of the journey.

I read from related appends in this forum that the gearbox light tend to flash after starting to indicate to the driver that an error/fault was encountered from the previous drive. Do you think this is what's happening with the problem symptom that I have described ?

Could it be the "lock solenoid" hard fault causing the problem as I have described in my earlier append ?

You mentioned checking the connectors. Which ones are you refering to ?


Regards,
Kenneth

 

[Chris]

Cold etc

I imagine that the problem relates to heat. The fact that it works fine when hot is GOOD. I still favour that a circiut is not properply connecting until some volts have flowed through it. (You could check by just starting it once and leaving it for 10 mins to see if it drives fine) If it is my diagnosis then pulling the plugs on the gearbox and cleaning/drying will cure. I believe that the LOCK referred to is the Torque Converter lock up which should operate at about 56MPH. It can be induced to lock by lifting the throttle slightly and you will notice about a 500RPM drop in engine speed. If this is working then it's definitely a wiring fault.
Now re-reading your note perhaps you do have a driving fault but this may just be the gearbox going into protective mode. I have had this! It clears when you restart.
Before any expensive repairs I would also drain the box and refill with new Fluid.

 

[terry]

Auto Gearbox Problem.

Hi Kenneth.

I'm from KL, Malaysia. Own the same car with the same problem as yours...

Anyway, here's what I guess. The gear switch selector is at fault. IE: Soft "incorrect gear level position" error. So far over a two months period, i had 3-4 occassion of this occuring.

There is no problem while the gear is in D, either Sports or Normal mode. Problem is when i downshift the gear to 3-2, sometimes the gearbox warning comes out and the gear refuses to change. I stopped the car and restart the engine and the problem goes away.

Otherwise, everything else runs fine. Anyway, to be safe, I won't be taking my car up to Genting...hehe.

No solutions yet, but just to let you know that u're not the only one facing the same problem.

Goodluck and let me know if you're able to get it fixed!

 

[terry]

Auto Gearbox Problem.

Hi Kenneth.

I'm from KL, Malaysia. Own the same car with the same problem as yours...

Anyway, here's what I guess. The gear switch selector is at fault. IE: Soft "incorrect gear level position" error. So far over a two months period, i had 3-4 occassion of this occuring.

There is no problem while the gear is in D, either Sports or Normal mode. Problem is when i downshift the gear to 3-2, sometimes the gearbox warning comes out and the gear refuses to change. I stopped the car and restart the engine and the problem goes away.

Otherwise, everything else runs fine. Anyway, to be safe, I won't be taking my car up to Genting...hehe.

No solutions yet, but just to let you know that u're not the only one facing the same problem.

Goodluck and let me know if you're able to get it fixed!