p0156 and p0325 for 1997 q45

[parshva]

Recently my infiniti started showing "check engine soon" light. So i decided to go for diagnosis check and found following codes:

p0156: Rear H02S Sensor, LH Bank

p0325: Knock Sensor, Bank 1

Can anybody help me in understanding these codes?

[paranoidjack]

Yep, that's an o2 sensor and a knock sensor. The knock sensor requires much more labor than the o2 sensor. Beware of failing o2 sensors, they usually fail in pairs...you have 4. 2 in front of the catalytic converter, and 2 behind.

o2 sensors are installed along the exhaust and send information to the ECM. Knock sensors are installed on the engine block and "listen" to the engine to make sure there is no pinging, and if detected, will retard the timing. A failed knock sensor leaves the timing retarded.

[maxnix]

And let me add KS are replaced in pairs along with subharness.

http://www.infinintipartsusa.com

[parshva]

Thanks to paranoidjack and Brian for replying soon.

I stay in New London, CT and contacted local mechanic for repair. He said that sometimes code P0325 is wrong and actual problem can be different. In this case, code P0156 is also there so according to him actual problem can be p0156(O2 sensor). I dont know how valid this information is. Let me tell you, I am very novice when it comes to car repairing.

I am also noticing that whenever i accelerate the car, the rpm goes very high and engine is producing little noise.

What can be the actual problem? are both sensor failed(as indicated by codes)?or O2 sensor failed(as per local mechanic).

I would also like to mention that 3 months ago somebody hit my infinity at right back and it caused misalignment of rear suspension. later, mechanic realigned it. is failure of sensor related to this?if not, what can be the problem? and how i can avoid failure of sensors in future?

[maxnix]

Crash not realted to sensor failures.

If you don't drive your car and don't start it, then sensor failures are trivial.

Let me suggest you spend a lot of time reading the FSM so you can get a clue about how your car should work.

http://www.nicoclub.com/FSM/Q45/

The VH41DE is quiet and and revolves freely to redline.

[Q45tech]

Better to think of KS and O2 as finally wearing out than an aburpt sudden failure. They have been declining since brand new and now exceed the point when they cause emission problems............thus the codes.

[JOHNQ]

i got the same codes when i first got my AE and i cleared several times and the only one that kept showing up was the o2 sensor right rear so hopefully that IS the problem.let me know what you come up with.