Today, I ran a scan on my car and found the following codes:

P2631: O2 sensor pumping current trim circuit high bank 2 sensor 1

P0174: O2 sensor system too lean

P0171: System too lean bank 1

need your help on how to solve this one

Also got this one too P0720 output speed sensor circuit

 

P0171 and P0174 are lean fuel codes for bank1 and bank2, respectively. P2631 is the top A/F sensor on the front bank. The SM says to troubleshoot the P2631 first before the P0171/0174 codes (because it could be causing the P0171/0174 codes). It could be a short, bad connection, or a bad sensor.

You might get lucky and fix it by merely replaced the bank 2 A/F sensor or you could be on a wild goose chase. Might be better to leave it to the professionals.

The P0720 is likely a short or faulty output shaft speed sensor. Again, unless you know what you are doing, I'd let the professionals handle it.

 

Thanks. I was initially thinking to just replace all four of them because I could do that myself. Since it may only be the bank 2 A/F sensor, I could have my mechanic take a look at it when i take my car to get the rack and pinion changed this weekend. I'll let you know what he tells me about the O2 sensors and the speed sensor.