The DEF tank appeared to be leaking. I brought the car to a shop where they said I needed a new DEF heater and DEF pump. Shop could not obtain parts due to backordering, and allowed me to obtain parts for them to install. I bought a Bosch Diesel Emissions Fluid pump for $269.99 from autohausAZ & a XeModeX DEF Repair kit at $549 from XEModeX where two weeks after installation "check engine light "illuminates."

I brought it back to Jason Auto in Telford, PA where diagnostics are run and he says both parts are bad. Two codes are reflected: P20E8 (reductant pressure too low) and P208D (reductant heater "B" control circuit/open - heating element failed - pump is faulty, will not turn on - seems to have burnt itself out). Brought to Mercedes Benz of West Chester PA to have them run diagnostics where code 20E823 - The pressure in the AdBlue system is too low and code 20BD1B - the output for heating element amble tank has an electrical fault or open circuit. the limit value for resistance has been exceeded.

Mercedes says that the parts installed failed and were not installed correctly; said that Mercedes vehicles don't like non-Mercedes parts - said cost to repair was $2,674.50. I declined to have them perform repairs because it seemed irrational/doubtful/suspect, etc... that two different parts from two different entities which were installed by a reputable shop went bad two weeks after installation, where Mercedes attitude was caustic/unsympathetic/highly overpriced.

I am now out of the money that I used to purchase the parts online ($818.99), labor & diagnostic fees to install the parts ($991.50). The parts are warrantied but they are still in the vehicle where I must have them removed and sent to parts distributors, all which will increase the cost of this nightmare. This is a known issue from Mercedes where it is unrealistic for these parts to fail as often as they do and prohibitively expensive to have the fixed/maintained. Dealer that I purchased the van from said the "check engine light" often illuminates and may not be accurate. I need help.