Another interesting gearbox fault.

ian_s · #1 1st March 2015, 11:02 PM

Evening all,

I have a gearbox issue I hope someone may be able to shed some light on, i'll try to describe it accurately. I'll also say that I'm a mechanic by trade but I have zero A8 or ZF trans experience.

Basically my daily journey is half B road and half on the M1. When the car is warmed up I slow down for the villages and the gearbox thumps/jolts down the gears, not every shift mainly the higher gears around 40mph. On the M1 it is absolutely fine with no jolt when I use kick down to shift. When I pull onto the slip road the inevitable jolt comes.
If I drive in S instead of D I have no issue at all, its like the higher revs sort it out.
Sometimes when stationary it also jolts as I move the selector into D or R.

In the couple of months I've owned the car I've changed the trans oil along with a new filter in the sump. I didn't find any nasty chunks on the magnets or burning in the oil.
I also changed the air mass meter as these can cause all sorts of auto trans issues.
The F125 selector position switch also needed changing to sort a 01119 fault in the abs fault memory. (pig of a job!!!)
All parts used were genuine.

The only re-occuring fault I have in the memories is the engine saying that both cats are defective, this has only came about since the air mass meter replacement.

Anyone have any suggestions? It's like it doesn't know when to shift so the jolt is the torque convertor trying to catch up?

Any help is greatly appreciated,

Thanks in advance.

evo · #2 2nd March 2015, 05:09 PM

Mine does the same, specifically when dropped from 4th to third when i slow down - yet curiously, only when the car is warmed up. When its cold, its smooth as ever.

ian_s · #3 2nd March 2015, 07:52 PM

Quote:

Originally Posted by evo

Mine does the same, specifically when dropped from 4th to third when i slow down - yet curiously, only when the car is warmed up. When its cold, its smooth as ever.

I think mine is 5th to 4th but could be the same as yours. The warming up and ok in S position makes me think it isn't a major gearbox issue. Does yours still do it in S position?

HPsauce · #4 2nd March 2015, 08:13 PM

Quote:

Originally Posted by ian_s

The F125 selector position switch also needed changing to sort a 01119 fault in the abs fault memory. (pig of a job!!!)

There has been many a discussion about the infamous "01119 - Gear Recognition Signal (Intermittent)" in ABS and at least one person here has solved it by cleaning the abs rings and detectors.
Did you have any other symptoms other than the code in memory and why did you decide to replace the F125 switch?

I ask because I get this code and occasional "oddness" in terms of a variable throttle response, but no obvious link between them.

ian_s · #5 2nd March 2015, 09:14 PM

Quote:

Originally Posted by HPsauce

There has been many a discussion about the infamous "01119 - Gear Recognition Signal (Intermittent)" in ABS and at least one person here has solved it by cleaning the abs rings and detectors.
Did you have any other symptoms other than the code in memory and why did you decide to replace the F125 switch?

I ask because I get this code and occasional "oddness" in terms of a variable throttle response, but no obvious link between them.

I should have explained it better, I had the 01119 stored all the time. Even after cancelling it would return after every journey. The trans module eventually gave me a similar fault reading which was for the f125 switch. Neither code has come back since i replaced it.

HPsauce · #6 2nd March 2015, 09:23 PM

Quote:

Originally Posted by ian_s

The trans module eventually gave me a similar fault reading which was for the f125 switch.

OK, thanks, not my situation.
If I clear the 01119 error it comes back "sooner or later" (usually sooner) but not after every journey.
And I have no other codes and no warning lights.

Do you recall what the TCU error was?

ian_s · #7 2nd March 2015, 11:10 PM

Quote:

Originally Posted by HPsauce

OK, thanks, not my situation.
If I clear the 01119 error it comes back "sooner or later" (usually sooner) but not after every journey.
And I have no other codes and no warning lights.

Do you recall what the TCU error was?

It seems to be a pain, i've just been researching 01119. I can't see how the speed senders can be connected to this fault but you never know.

The fault was 17090 Trans range sender f125 implausible signal. This ties in perfectly with 01119 as the abs unit can't understand the gear selection position. When I replaced it I thought that the state of the connector was more to blame than the f125 itself. Worth a loom at the connector first as the f125 is an awful job even on a ramp.

HPsauce · #8 3rd March 2015, 08:39 AM

Quote:

Originally Posted by ian_s

the state of the connector was more to blame than the f125 itself. Worth a loom (look?) at the connector first as the f125 is an awful job even on a ramp.

Yes, I've (along with others) looked at just about everything posted online about these issues and corrosion in the connector seems to be something to look at, and if possible deal with, first.