MFSW Fault code 01426

[gmac78]

Hi Guys,

My MFSW and paddle shift buttons have stopped working. The buttons are still illuminated, horn works, no airbag lights on, cruise control, steering wheel height adjustment, indicators etc work

Removed the clock spring to do a continuity check across the ribbon and cables too and from the buttons themselves. All checked out good with no issues.

With ignition on I get 11.5v feeding the buttons at the local 3 cable connection behind the airbag and around 8.5-9v coming out of the the buttons on the LIN bus cable ( not sure what voltage I should expect coming out off this cable?

If I press any of the MFSW buttons with the mulitmeter on the LIN bus cable/ground the voltage doesn't change, not even sure it should change?

I'm loathed to buy new buttons until I'm 100% sure that's where the problem lies.

Any help on this would be greatly appreciated. These electrical gremlins can be a nightmare to track down!

Cheers chaps

[Alan02]

VCDS would be helpful ( or an equivalent good diagnostic tester) to check that each button responds on the diagnostics when depressed rather than guessing inputs and outputs without knowing any values. You would also get any current trouble codes.

[gmac78]

Hi Alan.

I've got VCDS mate, none of the buttons respond to being pressed, the only code on the car as of today when I cleared some older ones was the 01426. There doesn't seem to be any info available on how to test the buttons with regards to voltages/resistances that would indicate if the the buttons are operating as they should.

Perhaps the fault lies elsewhere as the LIN bus signal goes back through clock spring ribbon then into the steering wheel control module, where it goes from there I have no idea.

Any experience with this yourself?

Cheers

[gmac78]

Is this not a common fault on Q7 guys?