list of codes, insight and help please

[dcovey]

You can't trigger the boost control valve in park, boost should be disabled unless you're in gear and moving.

[mrscullini]

8 ohms on the ground lead is not the problem. i shorted the ground lead to hard ground and no difference, codes just as before

i think i hear a vacuum leak after the engine has been turned off, does this make sense to anybody? i have not had a chance to look closely at it, that is for tomorrow.

[tailor]

i think i hear a vacuum leak after the engine has been turned off, does this make sense to anybody? i have not had a chance to look closely at it, that is for tomorrow.

This may be from your evap cannister, I know some models moved the evap cannister to the back of the car, anybody want to confirm the position on 2000 V70xc.

[mrscullini]

the evap cansister is in the back, it's not that but thanks.

i suppose i should check all the vac lines again. the funny thing is, i only seem to hear it after i shut off the car. with that, it may just be me.

i think i hear a vacuum leak after the engine has been turned off, does this make sense to anybody? i have not had a chance to look closely at it, that is for tomorrow.

This may be from your evap cannister, I know some models moved the evap cannister to the back of the car, anybody want to confirm the position on 2000 V70xc.

[jaluhn]

Is the AC on? If you do have it on (or have 'defrost' selected, since the AC is typically on for defrost) your vacuum leak may be the AC system. When you shut off the engine it takes ~15 seconds for the high side to equalized with the low side and what you hear is the gas flow through the orifice tube which sounds exactly like a vacuum leak. You'd hear it all the time except it's masked by the engine noise.

May not be what you've got, but it sure sound like it to me. I have never heard a vacuum leak that was heard after shutting the engine off like that unless it was from a major resevore, like the brake booster.

Either way, I would not be too worried about the possible vacuum leak, as I see no way it would cause those codes. My guess would be that you have something weird going on in the wiring harness, or possibly in the ECM itself.

Are you 100% positive the codes are getting cleared completely? Try erasing the codes then disconnecting the code reader, pulling the key, then try reconnecting the reader and see if it still has no codes. I have seen it happen where the reader will say it erased the codes, but really they somehow never got erased all the way. Not very likely, but still something to check.

Under what circumstances does the check light come back on? Assuming you erased all the codes and start it with no light on, does it take 5 minutes of driving to come back? 30 seconds?

Can you try checking codes before the light come on but after idleing / driving for a bit? How about right after it come on? What I'm curious about here is if all 6 or 8 or whatever codes are tripped at the same time and if there's any pattern.

Either way you cut it, you've got a very interesting problem, and I'm quite curious how it works out.
~John

[mrscullini]

Is the AC on? If you do have it on (or have 'defrost' selected, since the AC is typically on for defrost) your vacuum leak may be the AC system. When you shut off the engine it takes ~15 seconds for the high side to equalized with the low side and what you hear is the gas flow through the orifice tube which sounds exactly like a vacuum leak. You'd hear it all the time except it's masked by the engine noise.

May not be what you've got, but it sure sound like it to me. I have never heard a vacuum leak that was heard after shutting the engine off like that unless it was from a major resevore, like the brake booster.

Either way, I would not be too worried about the possible vacuum leak, as I see no way it would cause those codes. My guess would be that you have something weird going on in the wiring harness, or possibly in the ECM itself.

Are you 100% positive the codes are getting cleared completely? Try erasing the codes then disconnecting the code reader, pulling the key, then try reconnecting the reader and see if it still has no codes. I have seen it happen where the reader will say it erased the codes, but really they somehow never got erased all the way. Not very likely, but still something to check.

Under what circumstances does the check light come back on? Assuming you erased all the codes and start it with no light on, does it take 5 minutes of driving to come back? 30 seconds?

Can you try checking codes before the light come on but after idleing / driving for a bit? How about right after it come on? What I'm curious about here is if all 6 or 8 or whatever codes are tripped at the same time and if there's any pattern.

Either way you cut it, you've got a very interesting problem, and I'm quite curious how it works out.
~John

thanks for the info. i think this vacuum leak i speak of is in my head. i was unable to reproduce this weekend.

i tend to think it is something in a wiring harness as i am unable to find anything else.

i am pretty sure the codes are completely cleared. i clear them and then recheck and no codes appear. i have also disconnected the battery to "reset" the ecm and the codes reappear.

once i clear the codes, upon first start, i will have pending codes almost immediately. i do not have to go through any drive cycles to get the pending codes. once i turn off the car and restart, i get the cel. this further makes me think it is something in a harness.

it seems all codes are set relatively quickly and simultaneously. this again, make me think it is something in a harness.

[MadeInJapan]

Do the same codes reappear each time?
If so, you might be in for at least the front 02 sensor. Apparently the ECU is not getting the correct signal from it (from what you posted earlier).

[mrscullini]

Do the same codes reappear each time?
If so, you might be in for at least the front 02 sensor. Apparently the ECU is not getting the correct signal from it (from what you posted earlier).

same codes each time. i just replaced both o2 sensors and the maf sensor. i thought the sensor would solve the problem but no luck.

[MadeInJapan]

Something is mixing the wrong air/gas ratio...I suspect a leak of some sort- probably vacuum or even at your manifold.

[mrscullini]

Something is mixing the wrong air/gas ratio...I suspect a leak of some sort- probably vacuum or even at your manifold.

i'll check the manifold tonight.

a couple of months back i replaced the oil trap, what a royal pita. i replaced the gasket and check for leaks following re-assembly but i will check again.