Nightmare Scenario. Taking parents to Heathrow in 156 Sele. All good. Plenty of time. Approaching Buckden roundabout (A1) southbound, selespeed warning light starts flashing and car stays in 5th gear.
unable to change by any means
As I came to a stop at the roundabout, the car put itself into neutral and I got the warning beeps. It wouldn't go into gear manually and wouldn't select City mode.Too noisy at roadside to hear if pump was priming. Too dangerous to get out of drivers side.
Called up RAC and in meantime, checked all the usual areas, including all sensors. Sprayed a little WD40 on the underside sensors and then waited for RAC as i did not have hex key to remove SELESPEED ECU cover. I intended to unplug and replug the connector. Once we had battery disconnected, unplugged ECU, plugged it back in and connected battery and turned key to MAR. In effect, rebooted the sysyem. All working. !!!!
By this time, parents had got a taxi to Airport, to be on the safe side. It was Friday pm appraoching CAR PARK FULL o'clock on M25.
Thinking back to the earlier part of the journey, I had managed to clip one or two unavoidable tarmac craters which may just have been enough to knock a connection loose. No other explanation could be reasoned. Drive carefully out there but don't panic, a battery disconnect could be the answer.