This has been on for the last 500 miles.. All started at the time I replaced one of the handbrake cables.. This involved disconnecting the lambda sensor. So I took plug out again, then reconnected making sure it was firm. Then might went out for 100 miles or so, now back on permanently. As suited dodgy Linda so bought another but was unable to remove the old one that seems stuck solid. Is this warning light likely to be down to the sensor? Is there any way if resetting and seeing if it comes back?