obdII code help please

[dougs bs23]

OK dont shoot me because I have a nonmopar question.   OBDII code P 0403 egr flow curcuit low voltage.  Does anyone know what/where I need to troubleshoot/inspect to find whats giving me this code?   There must be a resistor or something causing this,, its a new egr valve on a saturn, 1.9 DOHC
As always,, thanks for any and all help

[Supercuda]

This code is usually associated with a fully electronic EGR valve. The GM valve is often troublesome, and if yours is a high-mileage unit, just bite the bullet and replace it now. Actual testing procedures for this code escape my mind, but they are as close as my work, where I can look it up tomorrow, if you still want to diagnose the code. What happens is this: the valve is removed, tested, cleaned, and reinstalled after it passes a final QC test, and then it throws a new code soon after, usually the opposite code (high voltage), or a repeat of the current one. Then you wind up replacing the valve, anyway. So, it's your choice: test it and replace it soon; or replace it now, and move on with your life. As a side note, I have once seen a burned wire for this code, and rodent damage to wiring can wreak havoc with the PCM. Check your wiring first, and clean connections, but expect to replace the valve.

[dougs bs23]

another valve  rwwwwww,  this one was replaced about 12k miles ago and i even got it from the local saturn dealer as a factory replacement part.   maybe I'll just clear it before i go to the emmissions test station, and after that who gives a flying,,,,,,,,,,,,. IMO this emmissions testing is just another way for the state to suck another 14 bucks out the each registered vehicle.

[sleepychallenger]

I would clear it and see if it comes back. when you replaced the other one, was it all carboned up? did you clean the carbon? how do the electrical connections look? vaccum lines (if any)?

[MEK-Dangerfield]

,,,,,,,,,,,,. IMO this emmissions testing is just another way for the state to suck another 14 bucks out the each registered vehicle.

Doug,


  It's nothing but another tax on us. They present emissions testing as a way to clean the air around here.   

The real deal is by pretending that they care about the air, they get funds from the Fed. Government for our hiways.

This test could be ALOT simpler. They could send you a questionaire asking if your "check engine" light is on. If you answer NO, you send them $14. If you answer YES, you get it fixed and send them $14.   


  Mike
   

[quagmire]

What year and model is this?  It's been a bit since I tested a Saturn EGR valve, but there should be three pins used solely for the EGR position sensor which is integrated into the valve.  There may be two others used for the EGR valve driver.  One is a 5 volt VRef, one is ground, and the last is signal return.  You will need to test the harness and valve by backprobing these 3 wires.  If both check out okay, the problem is either intermittent or the PCM has issues.  A scan tool makes this much easier, but you can rule out quite a bit with a DVOM or scope.  It is possible that you have a defective valve, but I wouldnt assume it either.  I am assuming it is like a typical PWM controlled late model GM EGR valve.  I need to know the make and model first to confirm though.

[Supercuda]

You didn't say that the valve had been replaced. It appears that you need to test the control circuit according to the GM guidelines. Are there any running problems? Does the light ever go out? Are there any other symptoms or weirdness associated with the check engine light being on? Now we have to get serious. I will start looking for the procedures. Don't even get me started on emissions testing, because I have been an emissions inspector in Colorado. I hate it too, but it is now a necessary evil of car ownership in many parts of our country. Quagmire has got the basic wiring correct, but it takes some investigation for the exact setup. I will post some more on Friday night.

[ViperMan]

I would check for sources of excessive resistance - it is detecting low voltage, not necessarily an open circuit.  Check the connection at the EGR, and check the terminals to make sure they aren't corroded.  Also, the EGR may ground through the block, so check to make sure it is fastened securely - if not, the seat may need to be cleaned.

It could also be a grounding issue on the PCM, but be very carefully handling the PCM as any spark can fry it, and they're much more expensive than a new EGR valve.

And I couldn't complain much about $14 for emissions...  PA State inspections can easily hit $50 depending on where you go.  My first inspection in Philly was $80!  I got smart after that.  Dude was freakin' (in-law) family, too!

Jeff

[dougs bs23]

ok, i totally agree with you mike, its a bunch of crap.,,
so the details are, 1999 saturn sc2, 1.9L dohc, 5 sp.
the only other symptom is on occassion when coming to a stop the idle drops to below 500 rpm and seems like its going to stall, then quickly revovers.
as for carbon build up,  i see it a "normal" all the passages were slightly built up but not enough to restrict flow.
as for the valvue, it is a 5 pin.
Over all its been a good commuter car with 38 mpg and i drive approximately 80 miles round trip daily most of which is highway.  other than routine maintenance the only thing i ever had t do was replace the clutch,  that was no fun becquse you have to pull the engine out completely, fortunately i have everything you need to do that surgurcial procedure.
So, today I'll pull the valve out clean it up again, clean the connection pins reinstall and clear the code.
After that, well,,,,,,,,,,, I'll let you know.
Thank you everyone for all the iinfo.

[quagmire]

How many ports are on the EGR valve?  I believe that one only has two, if that is the case the middle three terminals are for the EGR position sensor and the outer two are for the solenoid portion of the valve itself.  Like I said earlier, one is 5v, signal return, and sensor ground.  Of the outer two, one will be a constant 12v with ignition on and the other will be a PCM controlled ground.  Unless there is carbon build up on the valve pintle itself restricting it's movement carbon build up is probably not causing the problem. Generally P0401 is set if the passages are clogged.