1999 QX4 O2 Snesor... Help! Failed CA Emissions

[ndevlin]

Hi Guys,

I stumbled onto this site while googling for QX4 O2 Information. I have done some research on the forum here, but haven't found exactly the answers I am looking for so I appreciate any help.

As I said I failed CA Emissions today becuase of 4 OBD Fault Codes.

Here is what they said:

P0159 02 Sensor Slow Response (Bank 2 Sensor 2)P0158 02 Sensor High Voltage (Bank 2 Sensor 2)P0138 02 Sensor High Voltage (Bank 1 Sensor 2)P0140 02 Sensor CKT (Bank 1 Sensor 2)

Here are my questions:

How many 02 Sensors do I need to replace? I have 4 codes here, but only 2 locations for the sensors. Bank 2 Sensor 2 and Bank 1 Sensor 2?????

Do I need to replace 2 02 sensors or 4 02 sensors???

I located the FSM through the forum, but in it did not describe the exact location of these sensors? How do I determine when changing the sensor where Bank 2 Sensor 2 is or Bank 1 Sensor 2???

I checked with the infiniti dealership and the parts guy quoted me for 2 heated o2 sensors and 2 i guess not heated o2 sensors for $226.24 each!!! That seems outrageous!!! What non oem brands have you had success with? Best price? Easiest install? I have seen people talking about the universal 02's they seem like a good deal, are they good??

Thanks in advance!

Nick the newcomer

Modified by ndevlin at 2:37 PM 1/16/2009
Modified by ndevlin at 2:37 PM 1/16/2009

[fukkeneh240]

Hi Guys,

As I said I failed CA Emissions today becuase of 4 OBD Fault Codes.

Here is what they said:

P0159 02 Sensor Slow Response (Bank 2 Sensor 2)P0158 02 Sensor High Voltage (Bank 2 Sensor 2)P0138 02 Sensor High Voltage (Bank 1 Sensor 2)P0140 02 Sensor CKT (Bank 1 Sensor 2)

Here are my questions:

How many 02 Sensors do I need to replace? I have 4 codes here, but only 2 locations for the sensors. Bank 2 Sensor 2 and Bank 1 Sensor 2?????

Do I need to replace 2 02 sensors or 4 02 sensors???

I located the FSM through the forum, but in it did not describe the exact location of these sensors? How do I determine when changing the sensor where Bank 2 Sensor 2 is or Bank 1 Sensor 2???

I checked with the infiniti dealership and the parts guy quoted me for 2 heated o2 sensors and 2 i guess not heated o2 sensors for $226.24 each!!! That seems outrageous!!! What non oem brands have you had success with? Best price? Easiest install? I have seen people talking about the universal 02's they seem like a good deal, are they good??

this is for a pathfinder but pretty damn close if not exact for the r50's. IF the qx4 are different then ignore this message.

zerothread/174934

P0138 Rear O2S, Bank 1 Maximum Voltage Monitoring P0140 Rear O2S, Bank 1 High Voltage

and 158 and 159 are apparently also the two rear O2 sensors. look in the FSM again it's on page EM-8 for location (from 1997 FSM).

i cant give you an answer for other questions as i never had my O2 sensors go on me yet, but i would like to know the answer too.
Modified by fukkeneh240 at 9:14 AM 1/17/2009