A168 automatic transmission noise issue

[holymans]

Hi all,

I hope it is okay to ask for advice in my second post

I own a 2004 Mercedes A168 with automatic transmission (model 722.7). The car transmission has started to make a clicking noise while driving at the time when transmission is switching from gear 2 to 3. The noise is similar to electric contactor switch that is not working. The noise disappears at higher gears or at lower gears. No noise when parked or neutral either. I have had the car diagnosed with software DAS Xentry which suggests there is a fault with FGS, citing Y3/7n2, Y3/7n3 modules fault codes from #2000 through 2009. Other codes were 200B.
I have had the Y3/7n2 and 7n3 parts replaced, but the noise persists. DAS still identifies faults in the FGS module.

My questions:
1. What could this problem be and where should I look further?
2. If the problem is with the ECU module, can I program the module with DAS or do I need to have some other software?
3. Can I replace just the ECU module and would my transmission work with it or are the ECU modules programmed specifically for a VIN of the car?

Many thanks for your advice,

Adam

 

[Steve@Avantgarde]

Could it be a worn CV joint? The extra play in the joint is just making the gearbox give a fault code because its loading the drive shaft too much?

 

[holymans]

Hi Steve,

thank you very much for your reply. I have thought so too and checked the CV joints, but they are fine.

To better describe my issue:
- the shifting from gear 2 to 3 is not fluid - most of the times, there is the clicking noise. At other times, the gearbox successfully shifts into 3rd gear.
- the engine seems to lose power at the time when the gearbox is trying to shift into 3rd gear, slowing the car down.
- shifting gears from 1 to 2 and 4 to 5 work just fine, no noise

Thanks for your advice,

Adam

Could it be a worn CV joint? The extra play in the joint is just making the gearbox give a fault code because its loading the drive shaft too much?