We have learned some interesting news about the newer Piezo style injectors installed in many late-model diesel engines. They are suffering from something called ‘voltage drift’, which is something that we’ve actually seen on our Bosch EPS205 test bench when the ISA codes are checked and do not match. Voltage drift is basically an electronicinjector failure, and will cause running complaints. It is usually caused by moisture intrusion into the crystal stackinside the injector body. Bosch has been investigating this issue but doesn’t have a solution for the problem quite yet. Recently we’ve heard that Bosch may be going back to a solenoid triggered injector design (standard on the previous generation injectors), as they’ve now found the speed, control and performance of the newest generation solenoids has dramatically improved.
Also of note – beginning in 2015 – The emission controls computers can new monitor “Excessive DPFRegeneration”which is now an OBD-II code commanding the check engine light to turn on.