Chrysler Repair: 2005 Grand Caravan P0406 code., dodge grand caravan, 2005 dodge grand caravan

Question
Roland,
I found the PCM behind the left wheel well cover.  I removed C2 and checked all the wiring: no shorts and all wires checked ok.  Is it likely then that the PCM is causing the 5VDC to appear on pin 1 (the voltage is still there with the ignition on) of the EGR valve and then flagging the EGR valve (or its wiring) as having the problem?  What other way could I test this circuit?
Thanks,  Daniel

I already talked to you about this 2005 Dodge Grand Caravan regarding the EGR valve and the P0406 code.  The reason I didn't find the wire coloration the way you described is because I was looking at the BCM, not the PCM!  Please describe for me where the PCM is.  I went to the Dodge website and found a useful list of diagrams, but when it shows the PCM location, it's for a 2.4L engine, not my 3.3L engine.  On the picture, it shows the PCM at the rear of the engine (left side of the engine compartment), but I can't see it anywhere; the only thing I see coming out of the rear of the engine is the transmission.  Please tell me the location.
Thank you.  Daniel

Answer:  Hi Daniel,
I am uncertain because it depends upon whether your van has the separate pcm and tcm or instead the 'ngc' (a combined engine and trans controller in a single package). If the former then the pcm is located on the left inner fender directly adjacent to the battery. If the latter, then it is hidden in the area underneath the left headlamp and you access it by turning the wheels full left, lift the front end on that side, remove the panel just in front and to the right of the left front wheel called the inner splash shield, and behind that panel you will find a cavity where the ngc unit is located. So look first for the pcm, and if not found then look for the ngc.
I suspect it is the ngc because the specific engine wiring diagrams shows 4 separate 34-pin plugs whose wiring I described, while the old style pcm only has 2 40-pin plugs.
Roland
PS Thanks for generous rating and nomination.

Answer
Hi Daniel,
The number 1 pin may well show 5v as it is a tap off a variable resistor one end of which is on pin 2 and the other on sensor ground. So if the valve is positioned at the pin 1 end of the resistor then it would show 5v. When the egr is in a different position it will read less than 5.
The most helpful thing for me to do is to send you the specific trouble shooting procedure for the 0403 and 0406 codes and the circuit diagram for the egr. I can copy those off a CD and email those to you. But you will need to tell me your email address by means of a follow-up question and of course use the 'private' option. Although the site knows your email address I don't see it unless you specifically tell me.
Roland
PS I would appreciate your giving me another nomination as 'volunteer of the month'.  Thank you.