Volvo Repair: Warning light on 240, flash flash flash, example 121

Question
hi. my dad owns a volvo 240 (H reg, lambda sond), it recently, unfortunatly overheated. I think no damage has been done but i do suspect the thermostat to be seized closed. However when it overheated the Lambda Sond engine warning light came on the dash. My question is how do i find the trouble code and erase it / fix it? I work for Rover and am well aware of flash codes and other fault finding diagnostic machines. But what does the volvo 240 have to diagnose these ECU stored faults?

Answer
below is how to check for codes in the fuel and ignition systems.probably the ECT sensor was overheated when it got hot.

in the engine bay on the drivers side near the strut tower there is a small black box with a wire attached to it.place the wire in the terminal marked 2.turn ignition key on (not started)press the small button for 1 second and the code will be displayed as a series of flashes.a red led displays the codes.the code will be three digits.small pause in between flashes for a single number long pause between flashes for the next number.example 121 will be flash.....flash..flash.....flash.repeat three times or until first code repeats itself.to erase the code after all codes have been checked hold the button for a good 5 seconds then release the light should light steady,then press for another 5seconds.this will erase the codes.  email me the codes and i will tell you what they are..socket 2is the fuel system 6 is ignition.