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alexgraf
Joined: 17 May 2002 Posts: 319 Location: Michigan, USA
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Posted: Thu Jan 22, 2009 10:12 pm Post subject: Code 1221 |
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Hi:
Code 1221 lit up last night on my '95 325 iS. I have been doing some diagnostic before spending $80 for a new O2 sensor.
I am trying to determine if the O2 heater function is working properly. My question is: does the ECU provides voltage to the heater at startup or is always on. I measured the voltage with the engine warm and there is no voltage.
Thanks for your help. _________________
'95 325is
'99 528iT - a real SUV |
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mabm325
Joined: 09 Jul 2001 Posts: 572 Location: Montreal, Canada
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Posted: Fri Jan 23, 2009 9:08 am Post subject: |
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I believe the pre-heater is on only for a short period of time. You should check for voltage with a cold engine. It would not hurt to check the heater element resistance as well while you are down there. _________________ Mario
Hers: 1988 325iA/4 (232000 km)
Mine: 1995 325i/4 (384000 km) Sold!
2001 330i (233000 km) My new ride! |
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alexgraf
Joined: 17 May 2002 Posts: 319 Location: Michigan, USA
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Posted: Fri Jan 23, 2009 1:41 pm Post subject: |
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Thanks mabm325. I checked the resistance of the heating element and is about 3ohms, which at 13V, should give about 40Watts (reasonable for such a small device).
I will check the situation with the engine cold and reply. _________________
'95 325is
'99 528iT - a real SUV |
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alexgraf
Joined: 17 May 2002 Posts: 319 Location: Michigan, USA
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Posted: Sun Feb 01, 2009 2:29 pm Post subject: |
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Hi:
just an update. I installed a new O2 sensor and the ligth went off after three cycles of start, warmup, and stop.
The only thing still not clear is when the sensor heater is activated. I measured the heater voltage from the connector at startup (20 sec after startup and there was no voltage. Any clarificatons will be good addition to the board.
Thanks, _________________
'95 325is
'99 528iT - a real SUV |
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