I have a 2002 Dakota 4wd slt with 4.7l engine. It has been acting up lately and I had the code read and it says p0406 EGR Position Sensor High Voltage detected. Well searching around I found that the 4.7l doesnt really have an EGR system. Is this true? Any ideas what else this code could be? The engine idles high and surges up and down. I found a vacuum line that runs into the throttle body that was split and replaced it. It seemed to help for a short time.

Thanks!

 

I'm having the same code and can't figure out what it it... when the engine starts surging try turning off your a/c and see if it stops... It does on mine. If you find an answer tell me cuz i even took it to a shop and they couldn't figure it out.

 

Exhaust Gas Recirculation Sensor "A" Circuit High, technically you shouldnt even be getting this code... It doesnt even register on our trucks database on Mitchell 1... its goes from p0358, to p0420. Im thinking PCM issue?

 

In the winter time I get a p0420 all the time but no change in performance,just a little rough idle. I put some fuel injecter cleaner in and reset the computer and it goes away for about three weeks and then it starts up again,but I never get it in the summer months I think it has something to do with the ethenol that is in the fuel in the winter time. Try that for a cheap fix.

 

So does this mean that the 4.7 does not have an egr circuit?

 

My next check is the Throttle position sensor. After talking with some of my friends, I think this may be why the engine is surging. I have now noticed that at an idle, If I barely touch the gas pedal and I mean barely tap it, the engine will surge up to 2500rpm not when I tap it but after the tap.
The TPS is relatively inexpensive to swap out. Next I'm gonna pull the Idle Air valve and try to clean it. I heard that they frequently get deposits on them and make it malfunction.

Lee Snow you may want to have a look at the Idle air valve as it controls your idle speed and is supposed to idle the engine up when the AC compressor pulls in. I guess a malfunction could cause the engine surge when the AC is on.

 

Ok guys, I replaced the TPS and it seems to have fixed the problem. I reset the check engine light and it is still off. I'll just have to drive it a while and see if the problem is gone for good.

 

no these trucks do not have an EGR valve...

 

Well after a week or so of driving, the CE Light came back on. I did not notice exactly when it came on, but the truck is still running good. The TPS was definitely why the engine was surging. I may take the truck back to the auto store and see if it is still giving the same error code.