Hi folks, I recently had injector seals replaced. All good for a couple of days then while cruising at 60mph I had a very slight engine stutter, small amount of whitish smoke from exhaust and engine malfunction warning. 

This reset itself overnight, but later same day the engine malfunction showed again and engine management light stayed illuminated. 

I used the car the following day and it stalled and has not restarted since. 

Mechanic has pulled fault codes linked to exhaust temperature sensors. Front sensor showing approx half resistance of rear, so I'm thinking the front is the knackered one. This sensor is green and as far as I can work out is part 12B591 BB. 

With both sensors pulled car still won't start. Should it? I thought it would run without them, but of course I could be wrong. 

Busy ordering a new sensor (which is quite hard to come by!) 

Any suggestions? 

OK, so have replaced front sensor (BB) after lengthy delay awaiting delivery, and then finally car started after lengthy delay for correct software to reset egt sensor values. Car apparently ran, however while warming up cut out with rear sensor in dpf (AA) showing 400C while front showed 100C. Mechanic diagnoses rear sensor also knackered and needing replaced. 

Seems unlikely to me that both sensors would go simultaneously. Any other ideas?