940 auto transmition

arcturus · Apr 5th, 2019, 09:36

Hi, Is there any connection with the operation of the transition in AW auto and the rev counter. In my old 960 it seemed that there was some connection in the operation. When the rev counter started to fluctuate wildly this affected the transmission (the one with the sport button) which would change up and down. The rev counter on my 940 is starting to flicker and as yet has no effect on the transmission. It usually starts doing this early on in the journey then seems to right itself.It may just be cold and humidity.

Laird Scooby · Apr 5th, 2019, 10:21

It sounds like your old 960 had an igniton related problem and was feeding this information to the gearbox ECU which then responded by chaningn up and down.

However, without knowing exactly which box you have in your 940, it's probably not possible to say, rough rule of thumb is if it doesn't have cruise control or Sport/Economy modes on the gearbox, chances are the box won't be effected by the rev counter doing its little dance.

You're probably right on the humidity causing the problem but it might be worth removing the instrument cluster and cleaning the connections on the plugs that plug into it and the tracks of the PCB where they plug in.

Also worth removing the ignition amplifier module, cleaning the mating surfaces of the back of it and the heatsink on the inner wing with a non-abrasive solvent cleaner and adding some fresh heatsink compound before refitting it and checking the earth connection for it.

arcturus · Apr 5th, 2019, 10:42

thanks but you lost me after the second paragraph. Don't know what or where half these parts are.

Rversteeg · Apr 5th, 2019, 10:47

The rev counter on my 940 occasionally looses about 200 rpm. It can flicker between this too low value and the actual engine speed without having any influence on the engine running. As the rev counter gets its signal directly from the ignition coil, I do believe the ignition system is okay and the problem must be in the instrument cluster or indeed in the rev counter module itself.
As it only happens every now and then for many years now, I am not too bothered about it.

Laird Scooby · Apr 5th, 2019, 11:33

Quote:

Originally Posted by arcturus

thanks but you lost me after the second paragraph. Don't know what or where half these parts are.

The instrument cluster is right in front of you when sat in the driving seat, you'll find the plugs etc on the back of it.

As for the ignition amplifier module, usually on the left hand inner wing behind the headlight hidden by the air filter box.

I could explain further but your reply suggests you wouldn't be comfortable doing it - if i'm wrong on that, let me know and i'll explain.

arcturus · Apr 5th, 2019, 13:49

Thanks but as it seems to be not really a problem i will leave well alone. BTW always wondered what the funny panel with dials was, you live and learn

But really, I appreciate your input.

Laird Scooby · Apr 5th, 2019, 14:03

I've just re-read my post - i didn't intend to come across as sarcastic! That said, i've come across many people who geninely don't know the name of it and often refer to it as a "speed thingy"!

If it isn't a problem then probably best left alone.

360beast · Apr 5th, 2019, 15:46

Quote:

Originally Posted by Laird Scooby

The instrument cluster is right in front of you when sat in the driving seat, you'll find the plugs etc on the back of it.

As for the ignition amplifier module, usually on the left hand inner wing behind the headlight hidden by the air filter box.

I could explain further but your reply suggests you wouldn't be comfortable doing it - if i'm wrong on that, let me know and i'll explain.

Just thought I would add Dave that on a 940 turbo it is bolted just above the battery... still need to do mine!!! My list of jobs keeps growing.

Laird Scooby · Apr 5th, 2019, 16:14

Quote:

Originally Posted by 360beast

Just thought I would add Dave that on a 940 turbo it is bolted just above the battery... still need to do mine!!! My list of jobs keeps growing.

I keep forgetting they had two possible places for the battery and air filter Luke, depends on the model. As far as i'm aware, n/asp cars have the battery on the right and air filter on the left, turbo cars other way round although i daresay there are exceptions to this as well!

rwdkev · Apr 11th, 2019, 14:49

Quote:

Originally Posted by Laird Scooby

I keep forgetting they had two possible places for the battery and air filter Luke, depends on the model. As far as i'm aware, n/asp cars have the battery on the right and air filter on the left, turbo cars other way round although i daresay there are exceptions to this as well!

Based on every 700/900 I have ever seen to date, my understanding has always been:

TURBO PETROL & TURBO DIESEL : battery on LHS as air cleaner on RHS

N/A PETROL: battery on RHS as air cleaner on LHS

N/A DIESEL : battery on LHS as air cleaner on RHS

Apr 5th, 2019, 09:36	#1
arcturus arcturus Last Online: Today 07:31 Join Date: Mar 2006 Location: Sagres Portugal	940 auto transmition Hi, Is there any connection with the operation of the transition in AW auto and the rev counter. In my old 960 it seemed that there was some connection in the operation. When the rev counter started to fluctuate wildly this affected the transmission (the one with the sport button) which would change up and down. The rev counter on my 940 is starting to flicker and as yet has no effect on the transmission. It usually starts doing this early on in the journey then seems to right itself.It may just be cold and humidity. __________________ life's too short to drink bad wine

Apr 5th, 2019, 10:21	#2
Laird Scooby Premier Member Last Online: Today 01:27 Join Date: May 2012 Location: Lakenheath	It sounds like your old 960 had an igniton related problem and was feeding this information to the gearbox ECU which then responded by chaningn up and down. However, without knowing exactly which box you have in your 940, it's probably not possible to say, rough rule of thumb is if it doesn't have cruise control or Sport/Economy modes on the gearbox, chances are the box won't be effected by the rev counter doing its little dance. You're probably right on the humidity causing the problem but it might be worth removing the instrument cluster and cleaning the connections on the plugs that plug into it and the tracks of the PCB where they plug in. Also worth removing the ignition amplifier module, cleaning the mating surfaces of the back of it and the heatsink on the inner wing with a non-abrasive solvent cleaner and adding some fresh heatsink compound before refitting it and checking the earth connection for it. __________________ Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........

Apr 5th, 2019, 10:42	#3
arcturus arcturus Last Online: Today 07:31 Join Date: Mar 2006 Location: Sagres Portugal	thanks but you lost me after the second paragraph. Don't know what or where half these parts are. __________________ life's too short to drink bad wine

Apr 5th, 2019, 10:47	#4
Rversteeg Master Member Last Online: Yesterday 17:12 Join Date: Feb 2006 Location: Amersfoort (NL)	Flickering rev counter The rev counter on my 940 occasionally looses about 200 rpm. It can flicker between this too low value and the actual engine speed without having any influence on the engine running. As the rev counter gets its signal directly from the ignition coil, I do believe the ignition system is okay and the problem must be in the instrument cluster or indeed in the rev counter module itself. As it only happens every now and then for many years now, I am not too bothered about it.

Apr 5th, 2019, 13:49	#6
arcturus arcturus Last Online: Today 07:31 Join Date: Mar 2006 Location: Sagres Portugal	Thanks but as it seems to be not really a problem i will leave well alone. BTW always wondered what the funny panel with dials was, you live and learn But really, I appreciate your input. __________________ life's too short to drink bad wine

Apr 5th, 2019, 14:03	#7
Laird Scooby Premier Member Last Online: Today 01:27 Join Date: May 2012 Location: Lakenheath	I've just re-read my post - i didn't intend to come across as sarcastic! That said, i've come across many people who geninely don't know the name of it and often refer to it as a "speed thingy"! If it isn't a problem then probably best left alone. __________________ Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........

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