Replace without hassle,
Redesign to a life of the car ETM
Recall to replace all MM ETMs
Reimburse for costs alread incurred.
With the 10/200,000 eatended warranty the first and last have pretty well been covered. A recall without a redesign is sensless, so lets look at my ideas for a redisign.
So, let's take a positive attitude on the redesign. We can all think of ways of why it cannot be redesigned, lets look at how it could be designed. I do think that any redesign would have to have minimal effect on the overall system design, circuit board redesign and sofrware recoding. So I have limited my ideas to only the end caps.
While there may be some problems that cleaning might fix, or a software update the primary problem is with the potentiometers (variable resistors) that are used as throttle position sensors. After 30,000 to 100,000 plus miles the original design wears through the thick film resistors. For the 8644347 replacement this wear through is occuring as early as 7,000 as was reported from the UK
I have found two items that might be incorporated in a new end cap that would aleviate this problem.
First: A product by Wabash Technologies is their PRS 1047 non contacting rotary position sensor. The key is that it "is a form, fit and function replacement for the 1036 contacting sensor (potentiomenter). ---Typical applications are --- throttle position senors. I talked with them several months ago but the reply was that since Volvo was already a client of theirs, though on another product, they declined to comment. See
http://www.wabashtech.com/pdf/1047%20leaflet%20aw.pdf
[link edited by Matt -- removed trailing dot]
Second: Alps Technologies has "succeeded in developing a sensor resistor that supports one billion cycles." If the ALPS designed potentiometer was housed in something like the Bosch design, show below, it would accomplish several things. By using a superior resistor technology, resistors of the same value could be used, negating any need to redesign the circuit boards or the software.
First would be a long lasting thick film resistor, from 100 to 1000 times the life of the current thick film resistor.
Second, with the wider flatter wiper, insted of the multiple finger nail type wipers, the contact pressure would be lower.
Third, with the external connectors between the potentiometer and the ETM body, the end cap could be readily replaced.
