Volvo Repair: 240 fault codes, coolant temperature sensor, engine coolant temperature sensor

Question
i did what you said to do regarding what happened when my 240 overheated and the engine warning light came on. i got the folowing codes from the flash unit...  121 on fuel system and 224 on the ignition system. Can you tell me what these mean please.
thanks
Matt

Answer
the 224 is for the engine coolant temperature sensor(ECT).the sensor probably got damaged when it was overheated.I would replace it.the 121 is for the airmass meter but does not mean it is bad.I wouuld replace the ECT sensor then see if the 121 comes back on later.