1999 S70 T5 P0137 o2 sensor circuit low volts

bigmuse · Post by **bigmuse** » 04 Oct 2007, 13:03

As title says, i have a 1999 S70 T5 with a check engine light on with a P0137 "O2 sensor circuit low volts" (bank 1 sensor 2) code set. Does this mean I need to replace an o2 sensor? Which one would be bank 1 sensor 2? Thanks.

Post by **Ozark Lee** » 04 Oct 2007, 14:00

Bank 1 - Sensor 2 is the rear sensor but it may or may not be the sensor itself. I would start by cleaning the MAF sensor, particularly if you have a K&N air filter. To clean the MAF use either electrical contact cleaner or MAF cleaner. Spray it and let it dry. Don't scrub it or even touch it.

...Lee

Post by **MadeInJapan** » 04 Oct 2007, 15:10

I agree with Lee, but usually when a rear sensor code shows, it really is the rear sensor. However, my experience has been that when the front sensor code shows, it usually isn't the sensor (although it could be) but vacuum hoses or the MAF sensor.

bigmuse · Post by **bigmuse** » 09 Oct 2007, 22:04

is that considered the "downstream" sensor?

Post by **MadeInJapan** » 10 Oct 2007, 14:26

ummmm, probably so. Upstream would be the front one, I would think.

1999 S70 T5 P0137 o2 sensor circuit low volts

What do you think is wrong?