2002 pathy - new code while on road trip

[kentai3838]

Hi all,

I have a 2002 Pathfinder with 160k miles. To keep it brief, I just say - I just drove from New York to Florida visiting dad despite the fact that the car was not in top shape. Car had a existing CEL with code p0506 and p1456. It's a bit of annoyance because I need to give it gas each time it starts up or it will stall. Otherwise it runs fine. (I saw there is a few threads on the subject already. )

I did some prep work - changed engine oil, changed fuel filter, topped up brake fluid, topped up coolant etc.

During this trip, I got a replacement fuel cap - non Nissan one. As it turn out, it pulled some new codes p0442, p0455. I put the original cap back; clear the code.

About 400-500 miles later - I got p0139, p1147 in addition to previous p0506 and p1456. From what I can read, the driver side, rear oxygen sensor might be at fault. There is also some brief engine hesitation right after car starts - only happened a couple of times. MPG gotten worse.

Now that I made it to Daytona Beach, will be here for a few days before another 1000 miles trip back to NY. I am thinking as to what to do:

1) Do nothing; and hope it won't break down on my way back and get my mechanic in NY to fix it. Are these codes indicate anything serious that I should worry about?

2) Replace o2 sensor. Anyone know of reputable shop in Daytona Beach? Or is this something any can replace?

Thoughts?

Ken

[TheReplay]

P0506 is an IAC valve code... there are those that are more knowledgable than me on this board, but these pages are absolutely littered with the IAC valve problem... seems like a ton of them have popped up.

My thread has similar codes and is posted a few below this, but this was after i replaced/repaired IACV and ECM.

I also replaced the O2 sensor that corresponds to the fault code you had.

Mine is a 2001 with 167k.

My original symptoms were like yours, i brought to the dealer who said the fuse in the engine bay (#62 or #63 cant remember [ECCS2 location]) was blown though this was just part of the main problem with the IACV and ECM.

The dealer unplugged the IACV and i was able to drive it home, albeit with erratic idle symptoms (but it wouldnt stall on me if it was unplugged). I wasnt fixing it there, they wanted something like 2500-3000$.

[TheReplay]

The bank 1 sensor 2 O2 sensor is easy to get to, but may be seized so you have to be careful if attempting yourself. I hit mine with a torch from the get go and was able to break it loose and "back and forth" it out.

It is located on the passenger side after the cat.

I was able to pick one up for about 70 bucks.

The O2 sensor isnt going to help with your symptoms though.

[rgk]

I think you will make it back to NY.

The only code that you need to be concerned about is 0506: Idle Air Control System RPM Lower Than Expected. In this case, the P0506 is triggered when the PCM (powertrain control module) detects an engine idle speed that is lower than the desired (pre-programmed) RPM.

From obd-codes.com/p0506:

A P0506 DTC trouble code may be caused by one or more of the following:
A vacuum leak
An air restriction in the intake air path or exhuast
A faulty positive crankcase ventilation (PCV) valve
Damaged/failed/dirty throttle body
Internal engine problem
Failed PCM

P1456 is small EVAP leak. Don't worry about it for now. Replacing the rear oxygen sensor won't do anything, it's used only for emissions data. It doesn't affect the engine at all.

Focus on why your car is idling low. Start by looking for bad vacuum hoses and maybe perform the idle relearn.

[kentai3838]

I looked at the oxygen sensor yesterday. It looks intact; no rust on it. Should be able to get it out with proper tool but I can't find reach the other end of where the wire leads to. From what I read and as mentioned by rgk, this seems not a major thing.

Thanks rgk, will focus on p0506.

Ken

[kentai3838]

Just a follow up from my post few months ago. Thanks for this board - which give me and others so much information.

Regarding p0506 code, after my return to NYC, it pulled additional p0507(high idle) code and has erratic idle when engine is cold. When engine is warm, rpm is around 500 at idle. So, I was having rpm too low and too high at the same time. Thanks to this board, I took the ecu out and can see clearly the burned and cracked chip on IC17 - as many on the board has indicated.

I mailed ecu and got a place in Atlanta to rebuild for $90. I installed the rebuild ecu with a new idle air control valve. Car starts with a bit of hesitation; and it pulled a new code p0304. I let it warm up and rpm comes back down to 750. I clear the code and had about 600 miles on it so far, the misfire code hasn't come back; and car is idling fine now. The only thing is - I am not sure car "accept" air volume relearn - because it's idling 750 before and after I did the relearn. I also notice mpg is worse than before; probably because it's running normal now.

I hope this bit of information can be useful for someone else.

Many thanks.

Ken

[MisterH]

Did you go through the factory-prescribed re-learn procedure when you installed the new IACV?

[kentai3838]

Did you go through the factory-prescribed re-learn procedure when you installed the new IACV?

that's the instruction I followed:

Without CONSULT-II

1. Turn ignition switch “ON” and wait at least 1 second.
2. Turn ignition switch “OFF” and wait at least 10 seconds.
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic “PRE-CONDITIONING”
(previously mentioned) are in good order.
5. Turn ignition switch “OFF” and wait at least 10 seconds.
6. Start the engine and let it idle for at least 30 seconds.
7. Disconnect throttle position sensor harness connector (brown),
then reconnect it within 5 seconds.
8. Wait 20 seconds.
9. Make sure that idle speed is within specifications. If not, the
result will be incomplete. In this case, find the cause of the
incident by referring to the NOTE below.
10. Rev up the engine two or three times. Make sure that idle
speed and ignition timing are within specifications.