revving idle, codes thrown

[NCG8R]

2003 Pilot - Started today. When idling in Park, engine revs btwn 1000-2000 rpms. After ~1 min it goes to a very narrow idle rev (can't see on tach but I'd guess 1300-1500) and VTM-4 light comes on constant. Codes pulled at Auto Parts store were P0505 and P1491. I'm going to search for codes no but if anyone can help I'd be very thankful.

[rooster59]

I'd look for a bad vacuum line, look for 1 at the EGR valve first. Check PCV valve + hose.

If no vac leaks, I would suspect a crapped Idle Air Control valve.

P0505- Idle Control system malfunction

P1491- EGR Valve Lift Insufficient Detected

[rocky]

You seem to have a problem with the Idle Control and the EGR.

Go at these problems one at a time.

The IAC could simply be gunked up and require cleaning or replacement.

You Tube

You Tube

Here is a thread on the IAC with links to the part embedded in it.

Idle air control valve.

[NCG8R]

Thanks. I'll look at both. I replaced the EGR a couple of years ago and it's been fine ever since. Can I use normal carb cleaner for IAC? What do you thinhk about the "disconnecting the battery" possibility? Looking forward to a warm, sunny w'end so I can play under the hood. Cheers!

[NCG8R]

Checked all the hoses I could find after removing the plastice shield covering the engine.Could find nothing wrong. Pulled the EGR valve & cleaned it up - still erradic idling. Disconnected the battery, still erradic idling. While it was idling, tapped IAC, etc and things look good right now. Still no check engine light/VTM light. Will test drive longer tomorrow and see what happens. Seems to be IAC related so I will remove/clean/replace if/when it happens again. THANKS for all help!

[andrewjamesh]

I have a 2003. Wife called me at work informing me the Check Engine light and VTM-4 light came on while driving to pick up the kids. In addition, she felt the car stutter several times.

After reading several websights and posts, I went to the local autoparts store and purchased the OBDII (on board diagnostic II) reader for $82. I got the P-0505 code and a few systems were blinking. I found this thread describing how to clean the intake duct. I went and bought a can of carburetor cleaner for $5.

I removed the engine cover with the four 10mm bolts. I used pliers to open the clamp and remove the front hose. I used a flat head screw driver to loosen the large hose clamp at the intake duct. I then removed the hose to the intake duct. I also used a towel under the intake duct to catch excess spray and sprayed carburetor cleaner into the duct. There was some visable dirt. I also hit the rectangular opening on the bottom of the intake duct. I put it all back together and started the car. Took two attempts before it started. It ran rough for a few seconds then smoothed out.

I used the OBDII reader to reset the errors. It's been fine for five days now.

[humanoid]

Why would there be a build up of dirt there? There shouldn't be anything getting past the airfilter.

[andrewjamesh]

Originally Posted by humanoid

Why would there be a build up of dirt there? There shouldn't be anything getting past the airfilter.

How does the Idle adjust valve get dirty and require cleaning? Whatever does that is the same that built up in the intake duct. Next time I'll take a picture before cleaning it.