Bosch #VAE0280752029 pedal potentiometer

[MRichards]

I recently had intermittent limp home mode on the 3200GT which diagnosed as SD2 code P0225,intermittent pedal pot. failure.
Since the OE unit is no longer available I investigated the reason for failure. It was a 2 minute job to disassemble the part and I found microscopic scratches on all four of the ferrite tracks near the null point. It amazes me that such tiny defects disrupt the operation.
The pot. has obviously been designed such that the tracks can be easily removed & replaced.

Does anyone on here know of,or have access to,replacement tracks for the pedal pot. ? All four tracks are formed on a circular disc which is a push fit in the casing.

Alternatively,can the scratches be polished out to restore the surface ?

 

[allandwf]

Davy, on here, does a contactless one. I have an original spare I can lend if you need to prove it is the pedal pot, better going contactless though.

 

[davy83]

The ECU and pedal sensor system on the 3200 is seriously screwed up. Maserati made it far too sensitive in an attempt to make it super safe. I have dismantled a few of the Bosch units and they would have owrked fine in any other car, but as you say the 3200 won't have it. After buying a new one (when they were still available) and having it fail after 3 years, I decided I could do better and have been making new contactless replacement sensors for 6 or 7 years now. I have tried to make the new ones work round the crazy senstivity of the design so it does not cause any problems, and it broadly seems to work, more than 250 of them out there now and all still working to my knowledge.
I have tried to resurrect a couple of the Bosch units but the problem is that the two redundant outputs must be very closely matched, and produce a voltage that is within 0.015v of each other. I think Bosch Originally either laser trimmed the carbon tracks or just cherry picked the sensors with matching outputs, hence the £7-800 price tag when they were still available. So when doing repairs you need to find a way to match the two outputs and its not really very easy. When I did get an older one going it didn't last for more than a few months.
I also reckon all the second hand ones on e-bay are there because they were causing faults, as the one I got off e-bay didnt work in the car but appeared to be completely functional.

 

[MRichards]

Thanks for your info. I'll bow to superior experience.
I noticed several "used" units on eBay,money wasted I reckon.

 

[davy83]

Thanks for your info. I'll bow to superior experience.
I noticed several "used" units on eBay,money wasted I reckon.

Clearly its up to you, you might get lucky on e-bay! I was quite demoralised with this problem in the early years of owning my car having bought a new one and an e-bay one and it seemed such a mess, I was driven to make an alternative, which took me 2 years more or less to get working properly.