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O2 Voltage

I have a 01 Forester and the CEL has been coming on (P0420 - "Catalyst system inefficient for Bank 1"). I posted earlier to this group and it was suggested that it was the front o2 sensor. I'm finally getting around to addressing it. I had a friend use his OBD computer and read the sensor voltages. They were around 5V and I believe the typical value is suppose to be 0.1 to 0.8 V.

My friend suggested to cross check the voltages with a multimeter. His suggestion was to use a sewing needle taped to the multimeter probe and stick it through the insulation. I was wondering if there were any other suggestions out there?

Thanks, Bill

Reply to
Bill
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The "sewing needle taped to the probe" trick does work but can be kinda tricky with just tape. Wrap the tip and needle together with multiple turns of solid wire (18 ga works well) and then tape over that. I've done that when I didn't have the fancy factory-made needle-tip probes available.

Reply to
nobody >

Hi Bill, My '99 Outback was throwing the same code, it would go away for a while and then come back. I finally replaced the front O2 sensor and it hasn't come back since. I had 122k miles on it at the time. I didn't bother checking the voltage. I was so happy when the O2 sensor unthreaded very easily from the exhaust system. I made sure it was hot before I attempted removing it, but it came out a lot easier than I thought it would, I didn't have a the right socket but I was able to get at it with a smaller crescent wrench. Good luck

-Nick

Reply to
Nick Lamendola

did you use OEM O2 sensor or e.g. Bosh?

Reply to
alf

Reply to
Nick Lamendola

The replacement O2 sensor was made by Denso.

-NL

Reply to
Nick Lamendola

thx a lot.

Reply to
alf

NL-

Thanks for the reply. Nice to know that it's not difficult to replace.

Bill

Nick Lamendola wrote:

Reply to
Bill

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