The injectors can't really be repaired except by Bosch. The parts aren't available, so injector "reconditioners" simply swap parts about to make the injectors work again. Unfortunately this doesn't guarantee a perfect injector, and also changes the injector characteristics, making coding them a pointless exercise. Bosch will issue new codes calculated on the actual injector performance.Ahh I see. Was hoping to avoid a full new set of injectors. Hoping it could have been seals or o-rings. Would this only really happen with freezing temperatures?
However new vs Bosch rebuilt injectors, it's still better to simply install new injectors.
There's nothing to stop a single faulty injector from being replaced, rather than the whole lot.
A spill or leak back test can't be done on these injectors as the return line is held at 10 bar to ensure the injectors always have fuel in them. The injector uses 10 bar of fuel pressure as part of a hydraulic linkage between the piezo firing element and the injector needle . No pressure in the return would prevent the injectors from firing at all.Had the issue last few days when the temperature was above 5c so the glow plugs wouldn’t even be on. Will get a leak off kit and test the injectors