O2 sensor not working

Molibius · Post by **Molibius** » 06 Feb 2016, 15:54

I have seen previously this topic but never get to the final answer to this problem.

I have brand new (Bosch)oxygen sensor - downstream, and the scan tools shows 0 volts. This is the second sensor i installed. Both sensors were brand new made by Bosh. From what I read about it, previously, few guys had same problems. They were installing new sensors, checking the wring and connectors and at the end the volt reading on the second O2 sensor was zero. Now, some guys say, that its supposed to be zero, some other guys say it should read around 0.47 volts. Beside that the OBDII says that the # 2 O2 sensor has fault, so I think there is a problem .

Post by **Ozark Lee** » 06 Feb 2016, 19:11

Was this a Bosch Universal or a Bosch direct fit? The universals have been known to cause trouble at the splice junction so that would be the place to start.

It should not be zero volts.

...Lee

Molibius · Post by **Molibius** » 07 Feb 2016, 06:26

Yes it is direct fit , plug and play.
I will check the connector anyway.
Any more ideas ?

Post by **misha** » 07 Feb 2016, 14:29

Try with another scan tool.
Try with vol-fcr with live data version,for example.
Before that,give ecu a hard reset by disconnecting negative battery cable for about 15 minutes.

Molibius · Post by **Molibius** » 08 Feb 2016, 04:40

The car was scan by two different mechanics using OBDII readers. Always showing that the O2 sensor is not working. My scanner was the third one.

Post by **abscate** » 08 Feb 2016, 04:52

Where did you buy it? Lot of counterfeit Bosch stuff on market.

I think I would probe wiring for correct heater and voltage inputs once I knew the sensor wasn't fake

Molibius · Post by **Molibius** » 08 Feb 2016, 17:26

I got one from Europarts, and second one from Amazon.

Molibius · Post by **Molibius** » 07 Mar 2016, 13:40

Strange.
The car was scan using different scanner - by Volvo, and it shows that the O2 sensor is working and both fuel banks .
My scanner and two other one (independent mechanics) are showing fault in one of the fuel banks and zero volts for rear O2 sensor.
I have Autel Al 619 OBD II reader.