More code trouble

[Coach James]

When I scan my Grand Prix now, I get P0401 and the Cat and EVA lights blinking on the scanner. Help! I need to get this fixed as I have to get it inspected and tags renewed. Here in NC, you can't get tags without new inspection.

Coach

 

[Merkava_4]

http://www.garagejournal.com/forum/showthread.php?p=656997#post656997

What I said in your EGR thread is what you need to do; however, if you don't want to pay to have the car scanned, you can take your chances and go ahead and replace the EGR. Did you even put a test light on the pig tail to verify power to it? You should do that and make sure you at least have the 5V reference going to the EGR.

 

[Coach James]

I'm hoping to get it scanned Monday. That's when I'll be back at school and the shop will be open.

I missed the test light part of your post the first time I read through. I have a 12V test light, but would tht actually work?

Thanks

Coach

 

[Merkava_4]

I missed the test light part of your post the first time I read through. I have a 12V test light, but would tht actually work?

I'm thinking it should, but you might have to stick a paper clip into the pig tail and then contact the paper clip with the test light. I'm thinking it's probably a 3 pin connector; so the light will light up on only one of the ports; the port having the 5V reference signal going to it. Make sure your key is on/engine off.

I'm betting the EGR valve has a burnt out solenoid.

 

[BigE]

Clean the EGR passages in the intake manifold. If all passages are clear and the code persists, replace the EGR valve.

 

[Coach James]

I did remove the egr valve and the passageway into the valve looked clear. I used a brush on the surface and nothing came off though it was black but no visible build up.

Thanks

Coach

 

[Merkava_4]

Clean the EGR passages in the intake manifold. If all passages are clear and the code persists, replace the EGR valve.

You left out the part about troubleshooting the EGR valve. You want to first check to see if it's powered up by checking for the 5V reference, then if you find that it's powered up, you now plug the harness back into the pig tail and do a back probe check for the signal back to the PCM. If you've verified the presence of both reference voltage and signal voltage, now you go and hook up the Tech II scanner. The Tech II scanner will actually show you EGR valve movement if there is any. The EGR valve is suppose to move proportionally with an increase in engine RPM. You can control the engine RPM directly from the Tech II without touching the gas pedal.

 

[Merkava_4]

Coach, does your EGR valve look like this?

 

[krusty the clown]

I did remove the egr valve and the passageway into the valve looked clear. I used a brush on the surface and nothing came off though it was black but no visible build up.

Thanks

Coach

the blockage will be in the throttle body.

 

[Coach James]

No. Mine is this one.

http://shop.advanceautoparts.com/we...-BWD_18481608-P_282_R|GRPEMISAMS_532282080___


Coach

 

[Coach James]

the blockage will be in the throttle body.

Clearly I'm no mechanic and I've never done more than oil and brakes and belt on this car. How best to check and corect this? I've googled this for pics etc but nothing useful comes up.

Thanks

Coach

 

[Merkava_4]

the blockage will be in the throttle body.

There's no blockage anywhere!! Those valves burn out!!

 

[krusty the clown]

There's no blockage anywhere!! Those valves burn out!!

maybe but why not check for blockage first before you buy a valve?

 

[Merkava_4]

maybe but why not check for blockage first before you buy a valve?

Why not check the valve before checking for blockage?

 

[krusty the clown]

Why not check the valve before checking for blockage?

maybe because he doesn't have a scanner with bi-directional controls with him and would like to fix it before monday

 

[Merkava_4]

maybe because he doesn't have a scanner with bi-directional controls with him and would like to fix it before monday

LOL!!

 

[chadster1]

www.clubgp.com has a message forum for the Grand Prix. I got a lot of info from that site when I owned a Grand Prix

 

[rhandwor]

Advance Auto and Auto Zone will scan your engine free.

 

[Merkava_4]

Advance Auto and Auto Zone will scan your engine free.

That's not the kind of scanner he needs.

 

[Coach James]

Ok. How do I check for a faulty catalytic converter? I ran the car up to temp today then drove it onto ramps, put it in park and checked the temp along the exhaust with an IR thermometer. Got some odd readings. Much of the exhaust was ~270-300F but one spot was reading 440F. Possibly a error on my part but I got the same thing several times. The diference between the incoming and out going on the cat was ~20-25F.

What are the chances of a bad cat? It will probably be another week before I can take it to a shop the get checked.

Thanks for any help.

Coach

 

[krusty the clown]

Ok. How do I check for a faulty catalytic converter? I ran the car up to temp today then drove it onto ramps, put it in park and checked the temp along the exhaust with an IR thermometer. Got some odd readings. Much of the exhaust was ~270-300F but one spot was reading 440F. Possibly a error on my part but I got the same thing several times. The diference between the incoming and out going on the cat was ~20-25F.


Coach

what are you checking for? restriction?

the two way's i check them are with a backpressure guage (if i think it's plugged) or by watching the cat monitor sensor's on the scanner (if i think they are not working IE: cat monitor codes).


btw, what are the CAT and EVA light's your talking about?

 

[Coach James]

On my code scanner. When the egr code comes up, a little light with CAT and one with EVA also come on. Equus 3150 scanner.

And checking for blockage.

Coach

 

[krusty the clown]

On my code scanner. When the egr code comes up, a little light with CAT and one with EVA also come on. Equus 3150 scanner.

And checking for blockage.

Coach

i just downloaded the manual from thier site. those lights are just indicating that the monitors (in the pcm) have been completed. they do not indicate a failure.


have you fixed the p0401 yet?

 

[Joelfke]

I have alldata at my disposal if you need any info or a flow chart for the P0401

 

[Coach James]

Nope, still working on the 0401. I took off the air intake today and ran a can of sea foam through the throttle body. Got a good bit of white smoke. I cleared the codes and drove it some. I'll drive it again tomorrow and see if the code comes back. I appreciate all the help.

Coach

 

[krusty the clown]

you'll have to remove the throttle body and scrape the carbon out of the passages, just running cleaner through the intake won't do it.

 

[Coach James]

Any idea what the normal removel time is? Thanks again for the info.

Coach

 

[Merkava_4]

I'd be interested in knowing the percentage of EGR opening ... oh wait ... a code reader won't tell you that.

 

[77Montecarlo]

Those linear EGR valves are pretty common failures. Without real time data its hard to tell what the problem is though... Find an ASE certified tech with a real scan tool to diagnose it. Wouldn't take long to remove.

 

[Coach James]

All is well. The throttle body was the culprit. Removed it, cleaned out and no more codes. Car passed inspection and I was able to get my new tags so no more hiding from the police.

Many thanks for all the help from everyone. A great site this is.

Coach

 

[krusty the clown]

All is well. The throttle body was the culprit. Removed it, cleaned out and no more codes. Car passed inspection and I was able to get my new tags so no more hiding from the police.

Many thanks for all the help from everyone. A great site this is.

Coach

good deal. you can learn a lot from a dummy

 

[Papawrench]

First off I'm a pro I do this every day sometimes I make two days out of one. First thing is get a real scanner second do not use a test light on any computer controlled part a test light transfers a ground through it if the comp. Signal u r testing has less of a resistance than ur bulb u will burn ur PCM, this is why they make multi
meters.next p0401 is not a cat prob. It is soley egr.ck.The passages in the intake where the egr bolts up to make sure they r not blocked by black carbon,if it is clear pay a shop to diag and repair ur car as u don't have the tools to do it yourself.

 

[krusty the clown]

First off I'm a pro I do this every day sometimes I make two days out of one. First thing is get a real scanner second do not use a test light on any computer controlled part a test light transfers a ground through it if the comp. Signal u r testing has less of a resistance than ur bulb u will burn ur PCM, this is why they make multi
meters.next p0401 is not a cat prob. It is soley egr.ck.The passages in the intake where the egr bolts up to make sure they r not blocked by black carbon,if it is clear pay a shop to diag and repair ur car as u don't have the tools to do it yourself.

All is well. The throttle body was the culprit. Removed it, cleaned out and no more codes. Car passed inspection and I was able to get my new tags so no more hiding from the police.

Many thanks for all the help from everyone. A great site this is.

Coach

i think we got this one handled

 

[1stwarrior95]

sometimes I make two days out of one.

Hahahaha! Spoken like a true professional!

 

[quneur]

I am surprised he passed with the CAT and EVA not finishing their cycle.