If your glow plug light flashes on a Mk III Mondeo and your car goes into limp home mode don't panic. Even if a constant yellow engine warning light comes on too just step back and go for the least cost option. A faulty cam sensor will not give a DTC code when you run the dash diagnostic test (zero cost vs taking your motor to a garage to have DTC codes read off). Just hold in trip button for three seconds before switching on ignition to go into gauge sweep etc etc etc. You should see DTC / NONE come up after the first few dabs on the trip button. Then, if you've checked all the engine's electrical plug connections (zero cost), cleaned your cam and crank sensors (zero cost) and, the glow light / engine light continue to haunt you purchase a cam sensor for around £20 - £25 pounds from Ford or EBay. Pop it in and see if the glow plug light has now gone when you start up again. If it has but, the engine light is still there after start up switch off and try the following procedure. Switch the ignition on and off (without starting the engine) twenty, yes TWENTY times. You'll hear the "Program A New Key" beep after about six goes but carry on another fourteen times then, finally start the engine. Low and behold the dash will now be free of warning lamps and you'll only have spent 25 notes. Hope this helps anyone who reads this.