LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected)?
03-18-2012, 07:21 PM
#1
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LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected)?
Guys, I am trying to determine if I can just have my EGR solenoid plugged in without connecting the vacuum line to the EGR valve and still have the EGR system show as "ready" without any codes. Will just plugging in the solenoid (power and vacuum line going in) be enough?
My EGR monitoring is disabled in my PCM now, but I'm thinking about enabling monitoring of it to pass the state inspection. I need to know whether to buy an EGR solenoid or to try to make some type of simulator circuit to get the EGR system to show as ready and without any codes.
It looks like there are just two possible codes that could pop up: P0400 (Exhaust Gas Recirculation (EGR) system) and P0403 (Exhaust Gas Recirculation (EGR) solenoid control circuit).
My EGR monitoring is disabled in my PCM now, but I'm thinking about enabling monitoring of it to pass the state inspection. I need to know whether to buy an EGR solenoid or to try to make some type of simulator circuit to get the EGR system to show as ready and without any codes.
It looks like there are just two possible codes that could pop up: P0400 (Exhaust Gas Recirculation (EGR) system) and P0403 (Exhaust Gas Recirculation (EGR) solenoid control circuit).
Last edited by ChrisLS1Bird; 03-19-2012 at 11:42 AM.
03-19-2012, 01:55 PM
#2
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
you'd probably be better off trying to find some resister...
off his site "OBD-II cars usually do not like removal of the EGR system and will result in trouble codes. PCM re-programming to disable it's detection will take care of it. I have also heard of a couple other more elaborate ways to trick the PCM into thinking it is working."
off his site "OBD-II cars usually do not like removal of the EGR system and will result in trouble codes. PCM re-programming to disable it's detection will take care of it. I have also heard of a couple other more elaborate ways to trick the PCM into thinking it is working."
03-19-2012, 02:04 PM
#3
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
you'd probably be better off trying to find some resister...
off his site "OBD-II cars usually do not like removal of the EGR system and will result in trouble codes. PCM re-programming to disable it's detection will take care of it. I have also heard of a couple other more elaborate ways to trick the PCM into thinking it is working."
off his site "OBD-II cars usually do not like removal of the EGR system and will result in trouble codes. PCM re-programming to disable it's detection will take care of it. I have also heard of a couple other more elaborate ways to trick the PCM into thinking it is working."
I basically wonder what the PCM is looking for when it trips code P0400 (Exhaust Gas Recirculation (EGR) system) and code P0403 (Exhaust Gas Recirculation (EGR) solenoid control circuit).
03-19-2012, 02:13 PM
#4
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
thats what i'd do(especially if i had a radio shaq or something near by)
03-21-2012, 10:24 AM
#5
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
You can put a 10K ohm 1/4 watt resistor in place of the EGR solenoid to eliminate the P0403. However the P0400 is more complex in OBD2.. The PCM 'tests' the EGR by activating and deactivating at specific conditions and expects a change in the O2 readings and or MAP sensor readings. There is no way to bypass this other than PCM programming.
03-22-2012, 02:51 PM
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
The EGR flow diagnostic only look for a >1kPA change in MAP sensor reading when it cycles the EGR valve. I've seen a spoof which uses the signal to the EGR vacuum solenoid to switch a small resistance into the MAP sensor circuit to simulate the expected change in MAP. I don't have any more details than that though.
03-23-2012, 03:18 PM
#8
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
I made my own "EGR simulator" using a vacuum switch and some resistors. Basically, instead of the vacuum line going to the EGR valve, it goes to a vacuum switch. When the PCM commands the EGR valve to open, the vacuum closes this switch. I have some resistors connected from the 5 volt reference from the MAP sensor to the vacuum switch and then to the signal wire. When the vacuum switch closes, it increases the voltage signal to the computer and the computer "thinks" the EGR valve opened. I have been running this for over 3 years on my 96 (OBD II) and have NEVER had a PO400 code. I don't even have the tube from the passengers side header to the back of the intake on my car. I made everything just plug in, I did not cut any wires so that returning to stock would take about 1 minute. Probably less than $20 in parts.
04-05-2012, 10:59 PM
#9
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
PCM does have a timing table to compensate for the Exhaust being introduced to the intake. It advances timing up to 7* in some conditions.
Triggers when:
RPM = 800 - 2000
&
MAP = 65 - 25kpa
&
>=16mph
& Either:
ECT is hot and the IAT is >= 50*C
or
ECT is cold and the IAT is >= 82.25*C
Triggers when:
RPM = 800 - 2000
&
MAP = 65 - 25kpa
&
>=16mph
& Either:
ECT is hot and the IAT is >= 50*C
or
ECT is cold and the IAT is >= 82.25*C
12-19-2012, 12:58 PM
#10
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Re: LT1 EGR system - avoid codes by just plugging in solenoid (EGR valve disconnected
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