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Does anyone know what can cause a low voltage condition on the O2 sensors? My check engine light came one; and when I checked the codes, it said low voltage on O2 sensors. The voltage only goes up to .7 instead of 1 or .9. It seems unlikely that both O2 sensors would fail at precisely the same time with the same problem, so I am thinking it must be something else. Maybe a vacuum leak somewhere? It seems to run fine. Any suggestions for the next diagnostic step? Thanks in advance.
Low voltage is the failure mode of the O2 sensor. It causes the ECU to add more fuel than necessary, rather than dangerous lean condition.
A false low signal can also be caused at idle or coast down by a vacuum leak somewhere between the air sensor, and the head. This is unmetered air entering the engine.
Common causes of that are bad EGR gasket, bad intake gasket, or bad gasket on idle air bypass valve.
John C.
Both of mine failed, two months ago, at 118,000 miles. Dealership replaced and no problem since.
Both O2 sensors failed coincidentally at the same time? How much did it set you back, if you don't mind my asking? Thanks.Quote:
Originally Posted by JAFO
If you get a generic replacement, they're 50-60 each. I replaced all 4, and no more codes btw.
They are TOUGH to get out, even with correct socket(I split 2 trying)
Its worth paying to get it done, let someone else burn their arm or pull their back.
John
Diagnosis: Found both DTC's for both front 02 sensors - tested and found both 02 sensors not operating properly replaced both front 02 sensors and cleared DTC's - Tested OK.
Part #: 8-25312-200-0
Description: SENSOR.HTD OXY
List Price: $ 167.58 (x2)
Total Parts: $ 335.16
Total Labor: $ 225.60
Total Labor & Parts: $ 560.76