Code P1145 x 2= headache

[Pwnin O'Brien]

2003 Pathfinder SE (4x4 - 3.5)

Im getting codes:

P1491P0102P0113P0011P0021P0507

I know P1491 is the bypass valve. I can replaced that- it's going off because the exhaust from my broken muffler damaged it. Anyone know how much that cost?

The other codes came up and around the same time my car was loosing power. I would step on the gas, the rpm's would go up, but the car wouldnt move. Meanwhile, my oil change was wayy overdue. I did some research- took the throttle body off to clean it (lots of gunk), replaced the oil filter, air filter, and put in 10w-40.

The loss of power is gone. Drives normal, but RPM at start up and idle DO seem high. Also, those codes are coming up.

Help?

Thanks in advance!

Vannak

The high idle is normal after cleaning the throttle body and replacing the filter at the same time. You need to complete the idle air volume learning procedure so that the engine knows how much air it sucks in at idle and it will adjust your idle back to factory spec.

Here's a link to the idle air volume learning procedure (it starts at about halfway down the first post)... zer...dures

EDIT: Also, regarding the P1491 (Vacuum cut valve bypass valve), it is located on the very top of the engine (it sits right on top of the upper intake manifold collector, right next to the throttle body). I'm not sure that your exhaust could have caused the bypass valve to fail. This part is actually semi-serviceable since I just removed mine and opened it up and it's a fairly simple electromagnetic valve. Of course, if you aren't comfortable opening it up then I definitely would not recommend it, but you really don't have much to lose if it has failed.

The P0507 is just due to the idle being high from cleaning the throttle body; this won't come back after you complete the idle air volume learning procedure. The other codes (P0102, P0113, P0011, P0021) are all related to your MAF sensor. You may need a new MAF sensor. You could try cleaning your MAF sensor to see if that resolves the issue, but I doubt that it will, it seems like you have general MAF sensor failure.

I should have prefaced this entire post with one question: you didn't turn the ignition to ON (without starting the vehicle) or actually try starting the vehicle with ANY wire harnesses disconnected while you were performing said maintenance, did you?

[vannaksao]

P1491 Code:

P1491 is not the EVAP Service Port you're refering to; though, it is part of the EVAP system and should also be inspected. P1491 directly relates to the Vaccum Cut Valve Bypass Valve (vc/v bypass/v). The vc/v bypass/v sits in between your gas tank and the EVAP Canister. I've included a link that shows what the vc/v bypass/v looks like. I'll be ordering this part next week, and I'll keep everyone updated.

The picture:

If you are on your back, underneath the car, you'll be able to notice the vc/v bypass/v bolted the a bracket. Remove the two bolts that attach the bracket to the car, and then remove the bolt that holds the bypass valve to the bracket. This is what you will see

http://s1193.photobucket.com/albums/aa3 ... s%20Valve/

[vannaksao]

Replaced the valve, and cleared the codes. It's been about 60 miles and the SEL has not come back yet!