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Old 08-29-2012, 02:52 PM   #11
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Under what operating conditions are you determining there is no signal from the PCM to the EGR? Key on, engine off? Idle? Revving in park? Driving? You may be testing for a signal under conditions where there is not supposed to be a signal. That may be why Mike is trying to get you to focus on whether or not the EGR is the issue.
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Old 08-29-2012, 03:51 PM   #12
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Under what operating conditions are you determining there is no signal from the PCM to the EGR? Key on, engine off? Idle? Revving in park? Driving? You may be testing for a signal under conditions where there is not supposed to be a signal. That may be why Mike is trying to get you to focus on whether or not the EGR is the issue.
valid point, but i have already removed the egr from the equation as i have said now 3 times, it tests perfectly on and off the car at the same exact specs to the thousandth of a volt and ohm with a brand new one i have, so the EGR is not the problem, the problem is that somehow there is no 10-12 voltage coming from the pcm with the key on, like it should be doing every time just before u start the car, that voltage its supposed to send to the egr is what tests the closed position and compares to the value later that is sent back from the egr when you stop from over 50 mph, its when they dont match it throws that code, now obviously i got this code because it isnt getting any signal at all, now what are the common short, poor grounds, wires breaks, relays associated with the egr that might cause no voltage from the pcm is the problem, cuz i want to avoid taking the whole loom apart if there are common places for breaks and shorts, or if its not that at all
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Old 08-29-2012, 06:52 PM   #13
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When the car was built and the computer circuits energized for the first time the computer learned the EGR valve closed position signal from the valve position instrument that is built on top of the valve itself. Over time, when the instrument wears, a slightly different signal is sent to the computer and when it differs enough from the 'Valve Closed Signal', that the computer had learned, the trouble code P1404 is set and the 'Service Engine Soon' light comes on.

Replacing the EGR valve with a new one does not necessarily fix this problem because the 'Valve Closed Signal' between valves is slightly different and it is just pure luck if your new valve would give a 'Valve Closed Signal' close enough to your original valve'* signal not to set the trouble code. This is why the new EGR valve 'Valve Closed Signal' must be re-learned by the computer.

Try this:

1. Disconnect the wire harness from the EGR valve.

2. Turn key ON and erase the trouble code(*) (you need a scanner) from the car'* computer AND TURN KEY OFF IMMEDIATELY WHEN THE SCANNER SAYS CODES HAVE BEEN ERASED. DO NOT TURN KEY ON BEFORE YOU RE-CONNECT EGR WIRE HARNESS.

3. Re-connect EGR wire harness and your problem may be fixed.
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Old 08-29-2012, 07:10 PM   #14
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When the car was built and the computer circuits energized for the first time the computer learned the EGR valve closed position signal from the valve position instrument that is built on top of the valve itself. Over time, when the instrument wears, a slightly different signal is sent to the computer and when it differs enough from the 'Valve Closed Signal', that the computer had learned, the trouble code P1404 is set and the 'Service Engine Soon' light comes on.

Replacing the EGR valve with a new one does not necessarily fix this problem because the 'Valve Closed Signal' between valves is slightly different and it is just pure luck if your new valve would give a 'Valve Closed Signal' close enough to your original valve'* signal not to set the trouble code. This is why the new EGR valve 'Valve Closed Signal' must be re-learned by the computer.

Try this:

1. Disconnect the wire harness from the EGR valve.

2. Turn key ON and erase the trouble code(*) (you need a scanner) from the car'* computer AND TURN KEY OFF IMMEDIATELY WHEN THE SCANNER SAYS CODES HAVE BEEN ERASED. DO NOT TURN KEY ON BEFORE YOU RE-CONNECT EGR WIRE HARNESS.

3. Re-connect EGR wire harness and your problem may be fixed.
yeah im familiar with the egr trick, ive tried it several times with the original egr to see if that was the problem, course it didnt work, so i spent the better part of the last couple hours looking for shorts or breaks in any egr related wires to no avail, so i threw in the new egr for the heck of it, and no p1404 yet, but i do get p0405, did the relearn like i usually do, but still comes back, gonna try the relearn a few more times after it cools down, but is there anything else that might throw that with a new egr?
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Old 08-29-2012, 09:35 PM   #15
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I've heard of instances where the "EGR trick" doesn't work and the fix was to re-flash the PCM to "learn" the new initial pintle position. I obviously can't be sure that would fix your issue, but it has to be considered. Particularly if you can't find a damaged wire or connector.
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Old 08-29-2012, 10:01 PM   #16
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I've heard of instances where the "EGR trick" doesn't work and the fix was to re-flash the PCM to "learn" the new initial pintle position. I obviously can't be sure that would fix your issue, but it has to be considered. Particularly if you can't find a damaged wire or connector.
true i have only gotten the trick to work once, im hoping this will make twice, but we shall see, so after searching every fuse, wire, connector, pin, plug, etc... i cant find any reason for no voltage to the egr at keyed on position like its supposed to for that test 2, even with the new one in, so im lost on using the detailed test, because everything else checks out with either the old or new egr in or outta the car, but the intermittent p1404 code hasnt come back, and the new egr P405 code hasnt either, but then again i havent driven it enough to say yet, and that is the last problem i have, my scanner is basic, havent broke down to get one of the data logging/advanced controls ones yet, so im stuck waiting for enough warm up and 50 mph slow down cycles to get the emissions monitors to clear, well and the egr trick, which is usually after a few tries, i also read that egr trick works with the battery disconnected for long enough for the computer to revert to defaults and recalibrate, but havent tried it myself to verify it yet
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