Transmission codes are most likely cleared using the Body diagnostic port

 

Correct indeed; I found the unit hiding just behind the instrument facia between the CD-drive and PRND buttons, see below:

 

SOLVED!

Dear all, just happy to let you know that the problem is sorted and the car is back in business as it should. A big thanks to this forum that made it all work!

 

Reviving this old thread.....

Just noticed its been 3 years I performed the ground modification. From memory this ground modification applied to the whole pack of switches; i.e. a restored ground to make sure the whole pack of switches perform as they should.

They did for 3 years though. However, recently the P(ark) and R(everse) in particular have been playing up. D(rive) has not been an issue so far and N(eutral) is intermitted in terms of failing.

I know measuring resistance according to the P0705.pdf found in this thread would be the first check but before I tear my dash apart and LH wheel liner I'd like to put this matter into the group:

1) Perhaps a newer SB has been released since on Pre 09 cars?
2) Or could the buttons be at fault / is that a known issue when they get older? My car is an early October 2004 production (311th) car so these electrics are nearly 20 years of age.

Any guidance on how to start tackling this matter would be appreciated: I would be keen to check the buttons switching them out but I believe they all sport different connecters so I guess thats not an easy check.

Keen to hear, thanks!

 

20 years is a long time. Maybe replace your old switches with the nice glass ones first? May solve the problem and upgrade the looks at the same time. That’s where I’d start.

 

+1 on this, buttons are easily replaced and they have definitely served their purpose for 20 years. And you have the satisfaction of shiny new parts to look at.

 

I guess you are both making a valid point. I will try to measure resistance on the buttons one way or the other and ideally narrow the problem down to that.

 

The problem I've seen with buttons is there are 2 momentary contacts mounted on a board, and if values don't match it can cause a fault. Earlier cars would flag P2800 code if you didn't press directly in the center. Software update resolved a CEL for this but would still store the code.