EGR CEL resistor fix
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EGR CEL resistor fix
So my 97' SC300(200,000miles) has code P0401. I have tested the EGR valve itself and it seems to be fine. I have looked over the vac lines and everything seems to be solid. I have read where using a 10k 1/2watt resistor should turn my CEL off. Problem is in all of the threads I have found I can't seem to pin point which connector I need to stick the resistor in. Can someone point me in the right direction?
Thanks
Thanks
#6
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Hy!
Yes, please take pictures
Have your car the EGR Valve with under pressure? My 97 SC400 have a electric Valve.
Is this mod also possible by the electric EGR? I have the EGT sensor in front of the Valve in the intake manifold. If i close the EGT piping, after hard driving comes CEL with "no circulation EGR" . Is this problem fixed with the resistor?
sorry for OT
Thanks
Tom
Yes, please take pictures
Have your car the EGR Valve with under pressure? My 97 SC400 have a electric Valve.
Is this mod also possible by the electric EGR? I have the EGT sensor in front of the Valve in the intake manifold. If i close the EGT piping, after hard driving comes CEL with "no circulation EGR" . Is this problem fixed with the resistor?
sorry for OT
Thanks
Tom
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#9
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So here are a couple of pictures...
The first one shows the EGR gas temp sensor. It seems to be the sensor we need the ECU into thinking is working correctly. It has two wires coming from it that are several inches long. There is a connector mounted to the rear or the head/block that you need to get to and separate. It is very tricky to reach. I used a long regular screwdriver to pry it out of the mount it was attached to. Next hard part is getting the connector apart as there is very little extra wire to be able to get the thing into a better position to get at it.
Once apart I cut the wires a few inches from where it goes into the sensor.
For the most part the hard work is done. Next I took the loose connector and one 10K 1/2watt resistor and using some heat shrink tubing connected it to the two wire left on the connector. I covered it with a piece of tape to protect it till I come up with a better idea once I see if it fixes my problem.
Snapped it back into it's connector on the car and went for a drive. After about 40 miles sure enough the check engine light that I have been looking at for over a year went OFF!!!! Dash seems empty without it now!!!!
Hope this helps others too!!!
The first one shows the EGR gas temp sensor. It seems to be the sensor we need the ECU into thinking is working correctly. It has two wires coming from it that are several inches long. There is a connector mounted to the rear or the head/block that you need to get to and separate. It is very tricky to reach. I used a long regular screwdriver to pry it out of the mount it was attached to. Next hard part is getting the connector apart as there is very little extra wire to be able to get the thing into a better position to get at it.
Once apart I cut the wires a few inches from where it goes into the sensor.
For the most part the hard work is done. Next I took the loose connector and one 10K 1/2watt resistor and using some heat shrink tubing connected it to the two wire left on the connector. I covered it with a piece of tape to protect it till I come up with a better idea once I see if it fixes my problem.
Snapped it back into it's connector on the car and went for a drive. After about 40 miles sure enough the check engine light that I have been looking at for over a year went OFF!!!! Dash seems empty without it now!!!!
Hope this helps others too!!!
#13
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Just wanted to report another way for this resistor fix. I actually unclip the EGR temp sensor plug, remove the white plastic part inside the plug and insert the resistor in with each leg in either pin hole. Try to keep the physical resistor up close to the pins as possible to prevent snagging when you’re plugging it back in(think the resistor occupies the space the white plastic part used to sit) I then plug this back in the original harness. Went for a drive and bam no more P0401 and the thing looking STOCK! No cut wires, electrical tape, dangling unplugged connector or anything<<<important for visual inspection and this is the best way to conceal it.
A little more info if anyone wants to geek out, the manual calls for 9k ohms or less at Normal Operating Temperature for EGR temp sensor. http://www.97supraturbo.com/Trouble%...0401%20EGR.pdf page 10. So I actually use a 8k ohms resistor for this mod to account for any temperature effect. Also by hooking it up like this—in parallel to the OG sensor, the resistance will be very close but won’t go past 8k ohms (1/R1 + 1/R2 = 1/Rtotal) doesn’t matter what the EGR temp sensor resistance is (assuming much higher than our resistor since we’re getting a “insufficient flow” CEL)
A little more note for brain food, this mod works to get rid of p0401 CEL for if you have a working EGR system and failed EGR sensor or an individual failure within the EGR system (ECU, VSV, Modulator, deposit build up, vacuum line leaks). So for the prior case, essentially you can be actually having proper EGR operating. If this effect is undesirable for you you need to do really block off EGR or disable one of the mentioned system.
Last edited by shajbot; 03-13-21 at 11:52 PM.
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V8V8 (10-11-23)
#14
While working on getting condensation out of my driver side headlight assembly, I just added resistor to my 1993 sc300 to prevent the check engine light from my egr system…A couple years after blocking off my egr and living with egr check engine light.
Few notes and elaborated upon details of job from my year 2023 experience to add to other people’s write ups here …
below is an eBay photo of something that *resembles our egr sensor plug. On one end is the plastic electrical clip that plugs in to back of intake manifold near firewall. On other end is bolt that screws into egr pipe. The bolt end is easy to access from top of engine. The plastic plug is lot harder. I could get fingers on the top or the bottom of the clip, but not strong enough at the same time to unclip it. Pliers or screwdriver would help unclip it but I couldn’t get it too and didn’t want to crack connector.
This job would be much much much easier if you removed the whole thing and worked away from engine. If I moved the brake fluid reservoir, as I probably did when I blocked off my egr, I probably could have gotten to it better.
So I worked with it on car. Use wire cutters and cut off sensor side as close to bolt as possible. Place cut off bolt piece in labeled plastic bag to save for posterity—Ha! Slide down the casing protecting cord from heat and there are 2 very thin wires coated in rubber. Carefully strip inch or so off each of these with wire stripping tool. Probably really easy to cut all way through wire since so small in diameter, especially while leaning over engine to access these short wires.
take out a resistor from the box (see bottom photo below for resistor pack I ordered off Amazon—note power and resistance values there too) and attach one end of resistor to one wire, the other end to the other wire.
It’s hard to twist each end of the resistor to the egr wires since the egr wires are braided and don’t really twist, while the resistor wire is thin and flimsy. Due to access, I couldn’t get electrical tape to wrap the wires and stay in place so I got some shrink wrap tubing. Used an inch or so tubing to fit over each pair of twisted wires and heat gun to shrink it. Lots of failed attempts, trust me. When I got the tubing in place I held it with pliers while I applied the heat from the gun.
There is a metal hook piece that held this originally located egr wire away from engine block that I used to hold my newly spliced and wrapped wires. I drove for the day and check engine light stayed off. Because my battery had been disconnected, the check engine light had cleared. Later I used some high temp electrical tape to cover the exposed resistor. Used zip tie to better attach it to metal hook.
The end
Few notes and elaborated upon details of job from my year 2023 experience to add to other people’s write ups here …
below is an eBay photo of something that *resembles our egr sensor plug. On one end is the plastic electrical clip that plugs in to back of intake manifold near firewall. On other end is bolt that screws into egr pipe. The bolt end is easy to access from top of engine. The plastic plug is lot harder. I could get fingers on the top or the bottom of the clip, but not strong enough at the same time to unclip it. Pliers or screwdriver would help unclip it but I couldn’t get it too and didn’t want to crack connector.
This job would be much much much easier if you removed the whole thing and worked away from engine. If I moved the brake fluid reservoir, as I probably did when I blocked off my egr, I probably could have gotten to it better.
So I worked with it on car. Use wire cutters and cut off sensor side as close to bolt as possible. Place cut off bolt piece in labeled plastic bag to save for posterity—Ha! Slide down the casing protecting cord from heat and there are 2 very thin wires coated in rubber. Carefully strip inch or so off each of these with wire stripping tool. Probably really easy to cut all way through wire since so small in diameter, especially while leaning over engine to access these short wires.
take out a resistor from the box (see bottom photo below for resistor pack I ordered off Amazon—note power and resistance values there too) and attach one end of resistor to one wire, the other end to the other wire.
It’s hard to twist each end of the resistor to the egr wires since the egr wires are braided and don’t really twist, while the resistor wire is thin and flimsy. Due to access, I couldn’t get electrical tape to wrap the wires and stay in place so I got some shrink wrap tubing. Used an inch or so tubing to fit over each pair of twisted wires and heat gun to shrink it. Lots of failed attempts, trust me. When I got the tubing in place I held it with pliers while I applied the heat from the gun.
There is a metal hook piece that held this originally located egr wire away from engine block that I used to hold my newly spliced and wrapped wires. I drove for the day and check engine light stayed off. Because my battery had been disconnected, the check engine light had cleared. Later I used some high temp electrical tape to cover the exposed resistor. Used zip tie to better attach it to metal hook.
The end
#15
While working on getting condensation out of my driver side headlight assembly, I just added resistor to my 1993 sc300 to prevent the check engine light from my egr system…A couple years after blocking off my egr and living with egr check engine light.
Few notes and elaborated upon details of job from my year 2023 experience to add to other people’s write ups here …
below is an eBay photo of something that *resembles our egr sensor plug. On one end is the plastic electrical clip that plugs in to back of intake manifold near firewall. On other end is bolt that screws into egr pipe. The bolt end is easy to access from top of engine. The plastic plug is lot harder. I could get fingers on the top or the bottom of the clip, but not strong enough at the same time to unclip it. Pliers or screwdriver would help unclip it but I couldn’t get it too and didn’t want to crack connector.
This job would be much much much easier if you removed the whole thing and worked away from engine. If I moved the brake fluid reservoir, as I probably did when I blocked off my egr, I probably could have gotten to it better.
So I worked with it on car. Use wire cutters and cut off sensor side as close to bolt as possible. Place cut off bolt piece in labeled plastic bag to save for posterity—Ha! Slide down the casing protecting cord from heat and there are 2 very thin wires coated in rubber. Carefully strip inch or so off each of these with wire stripping tool. Probably really easy to cut all way through wire since so small in diameter, especially while leaning over engine to access these short wires.
take out a resistor from the box (see bottom photo below for resistor pack I ordered off Amazon—note power and resistance values there too) and attach one end of resistor to one wire, the other end to the other wire.
It’s hard to twist each end of the resistor to the egr wires since the egr wires are braided and don’t really twist, while the resistor wire is thin and flimsy. Due to access, I couldn’t get electrical tape to wrap the wires and stay in place so I got some shrink wrap tubing. Used an inch or so tubing to fit over each pair of twisted wires and heat gun to shrink it. Lots of failed attempts, trust me. When I got the tubing in place I held it with pliers while I applied the heat from the gun.
There is a metal hook piece that held this originally located egr wire away from engine block that I used to hold my newly spliced and wrapped wires. I drove for the day and check engine light stayed off. Because my battery had been disconnected, the check engine light had cleared. Later I used some high temp electrical tape to cover the exposed resistor. Used zip tie to better attach it to metal hook.
The end
Few notes and elaborated upon details of job from my year 2023 experience to add to other people’s write ups here …
below is an eBay photo of something that *resembles our egr sensor plug. On one end is the plastic electrical clip that plugs in to back of intake manifold near firewall. On other end is bolt that screws into egr pipe. The bolt end is easy to access from top of engine. The plastic plug is lot harder. I could get fingers on the top or the bottom of the clip, but not strong enough at the same time to unclip it. Pliers or screwdriver would help unclip it but I couldn’t get it too and didn’t want to crack connector.
This job would be much much much easier if you removed the whole thing and worked away from engine. If I moved the brake fluid reservoir, as I probably did when I blocked off my egr, I probably could have gotten to it better.
So I worked with it on car. Use wire cutters and cut off sensor side as close to bolt as possible. Place cut off bolt piece in labeled plastic bag to save for posterity—Ha! Slide down the casing protecting cord from heat and there are 2 very thin wires coated in rubber. Carefully strip inch or so off each of these with wire stripping tool. Probably really easy to cut all way through wire since so small in diameter, especially while leaning over engine to access these short wires.
take out a resistor from the box (see bottom photo below for resistor pack I ordered off Amazon—note power and resistance values there too) and attach one end of resistor to one wire, the other end to the other wire.
It’s hard to twist each end of the resistor to the egr wires since the egr wires are braided and don’t really twist, while the resistor wire is thin and flimsy. Due to access, I couldn’t get electrical tape to wrap the wires and stay in place so I got some shrink wrap tubing. Used an inch or so tubing to fit over each pair of twisted wires and heat gun to shrink it. Lots of failed attempts, trust me. When I got the tubing in place I held it with pliers while I applied the heat from the gun.
There is a metal hook piece that held this originally located egr wire away from engine block that I used to hold my newly spliced and wrapped wires. I drove for the day and check engine light stayed off. Because my battery had been disconnected, the check engine light had cleared. Later I used some high temp electrical tape to cover the exposed resistor. Used zip tie to better attach it to metal hook.
The end