I have a 1990 740GLE I recently purchased a new oxigen sensor cause it was givin code 221(Heated Oxygen Sensor(Rich mixture/part throttle),it alsohas this code 321(Cold start valve-signal missing.) only that codeappear now, If I tried to erase it the red light start flashing very quickly and weird noises from the engine appear then it don't erase , I 've disconnected the negative cable on the battery to erase codes no chek engine light then after the engine start it starts a little misfire and the check engine light come on quickly what should about code 321 Do I have to replace air cold control valve or check cables or something like it any help would be aprreciate it thanks in advance.

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Gabyman97
1990 740GLE
1992 240DL
1994 940TurboWagon
1999 S80 2.9

 

Any advise for me????????????????????????????

 

you should first check and see if the cold start valve is connected. it's indicating there is no signal. see if you get voltage from the cpu. unplug and then replug it in.

 

i do not think it will affect drivability. all it does is injector more fule when the weather is under 60deg