Hi Arnold,

Usually, timing chains don't come with a set replacement schedule, as they're supposed to be designed for the life of the engine. However, the chain in the 2.2-litre diesel Mazda engine you have is known to stretch and cause many issues, so it does need replacement. The crankshaft sensor error is likely to be a symptom of the chain stretching and you should get the car looked at right away, as, if the timing slips, it can do massive engine damage.