Hybrid warning light switches on then goes off

Hello all,

Every 325 miles or so my hybrid warning light seems to come on and then after about 50 miles is goes back off with no change in the car's handling or performance. The car has done 181k miles or so and I replaced the hybrid battery with a second hand one last year. The problem with the light goes on and off again started a few months ago I think.

One of the warnings light is on, something to do with emmisions according to the mechanic but he did not think it was worth the money to fix it. It has been on for over a year.

The car is getting an MOT in January so I am not keen to spend large amounts of money on it until I know whether it is going to pass or not.

Does anyone recognise this 325 mile - 50 mile pattern.