Disable the EGR system the (mostly) Toyota way

[alaskacruiser]

Ebag- thanks for the update! Any info on whether this disables the modulator? You mentioned you were going to test this in a previous post...

Also, I just stopped by my local Toyota dealer and they said the part listed (82824-35020) is not available anywhere. Can anyone confirm this? I need to contact CDan, I know...

 

[Ebag333]

Ebag- thanks for the update! Any info on whether this disables the modulator? You mentioned you were going to test this in a previous post...

No, I (unfortunately) haven't gotten around to it yet. Got too many projects on my plate:

• Finish my rear shock (yes yes, I only have 1 left to do!).
• Finish my sliders.
• Finish my rear e-locker armor.
• Weld on a few spots of additional armor (lower rear control arm mounts, etc).
• Finish my X-Link.
• Test disabling EGR system on the truck.
• Work on various multiple remodeling projects around the house.

(Not necessarily in that order.)

Guess which one that wants done first? For some reason she can't seem to see the importance of me testing the EGR bypass on her truck.

Also, I just stopped by my local Toyota dealer and they said the part listed (82824-35020) is not available anywhere. Can anyone confirm this? I need to contact CDan, I know...

I would think they should be able to order it. It might need to come from Japan though if they did. I think Mot looked into it and was told that they could make more if someone ordered some.

Worst case scenario, just get a bit of wire or a paper clip and bypass it that way.

 

[UWdave]

Ebag- thanks for the update! Any info on whether this disables the modulator? You mentioned you were going to test this in a previous post...

The redneck guide:

1. Unplug the temp sensor.
2. Take a paperclip.
3. Stick one end of the paper clip into the plug (ECU side, not sensor side).
4. Stick the other end of the paper clip into the plug. (Other open hole.)
5. Duct tape in place.
6. Step #6.

So I'm confused.

If you do nothing more than the redneck guide, is the EGR system disabled? What is this talk about modulator?

 

[UWdave]

Nobody can answer my question?

 

[Ebag333]

The part that is not sure is if bypassing the temp sensor actually keeps the EGR modulator closed.

There are a couple scenarios here that can happen.

1) Bypassing the temp sensor disables the feedback to the ECU, so it doesn't throw a CEL if the EGR modulator valve doesn't open. The EGR modulator valve no longer opens.

2) Bypassing the temp sensor disables the feedback to the ECU, so it doesn't throw a CEL if the EGR modulator valve doesn't open. The EGR modulator valve still opens if it is there and functioning.


What I need to do is throw a paper clip in the truck and drive it around and see if the EGR pipe gets hot. If the EGR pipe gets hot, then it's opening. If it doesn't, then it's not. I know that the EGR system on the truck is currently functioning properly, so her truck is a good test bed for this.



Something else to keep in mind is that your EGR could be failed partially open. Even if the ECU never tells it to open, it'd still let exhaust gas cycle through there.

 

[HarleyHetz]

Now THAT'S a pretty engine!!

 

[kup99]

ok, i'm an idiot, but I do want to do this!!

is there any way to post very detailed, step by step pics.... I don't want to screw things up, and I don't understand the terminal part!!

sorry

edit: should mention I want to do the paperclip/wire way!!

 

[kup99]

The part that is not sure is if bypassing the temp sensor actually keeps the EGR modulator closed.

There are a couple scenarios here that can happen.

1) Bypassing the temp sensor disables the feedback to the ECU, so it doesn't throw a CEL if the EGR modulator valve doesn't open. The EGR modulator valve no longer opens.

2) Bypassing the temp sensor disables the feedback to the ECU, so it doesn't throw a CEL if the EGR modulator valve doesn't open. The EGR modulator valve still opens if it is there and functioning.


What I need to do is throw a paper clip in the truck and drive it around and see if the EGR pipe gets hot. If the EGR pipe gets hot, then it's opening. If it doesn't, then it's not. I know that the EGR system on the truck is currently functioning properly, so her truck is a good test bed for this.



Something else to keep in mind is that your EGR could be failed partially open. Even if the ECU never tells it to open, it'd still let exhaust gas cycle through there.

Any word on this??

 

[gotmud]

Now THAT'S a pretty engine!!

After two weekends of running rock garden trails, that's about the only "pretty" piece left

 

[96r50]

The part that is not sure is if bypassing the temp sensor actually keeps the EGR modulator closed.

There are a couple scenarios here that can happen.

1) Bypassing the temp sensor disables the feedback to the ECU, so it doesn't throw a CEL if the EGR modulator valve doesn't open. The EGR modulator valve no longer opens.

2) Bypassing the temp sensor disables the feedback to the ECU, so it doesn't throw a CEL if the EGR modulator valve doesn't open. The EGR modulator valve still opens if it is there and functioning.


What I need to do is throw a paper clip in the truck and drive it around and see if the EGR pipe gets hot. If the EGR pipe gets hot, then it's opening. If it doesn't, then it's not. I know that the EGR system on the truck is currently functioning properly, so her truck is a good test bed for this.



Something else to keep in mind is that your EGR could be failed partially open. Even if the ECU never tells it to open, it'd still let exhaust gas cycle through there.

I was doing some reading last night and found this site: Automotive Training and Resource Site. It has a number of technical articles from Toyota. Article #32 talks about temperature sensors and how they work, and on page 5 it shows that connecting a jumper wire in place of a temperature sensor will tell the ECM that the sensor is hot. So it seems that doing this mod would trick the ECU into believing that the EGR temp sensor is seeing very high temperature (no resistance in the circuit). This is all IMO, YMMV etc


Article #61 is about the EGR system and is a good read about how it works, what it does and why it is in place.

 

[Ebag333]

ok, i'm an idiot, but I do want to do this!!

is there any way to post very detailed, step by step pics.... I don't want to screw things up, and I don't understand the terminal part!!

sorry

edit: should mention I want to do the paperclip/wire way!!

Any word on this??

I will try and post up the easy way today after work.

I was doing some reading last night and found this site: Automotive Training and Resource Site. It has a number of technical articles from Toyota. Article #32 talks about temperature sensors and how they work, and on page 5 it shows that connecting a jumper wire in place of a temperature sensor will tell the ECM that the sensor is hot. So it seems that doing this mod would trick the ECU into believing that the EGR temp sensor is seeing very high temperature (no resistance in the circuit). This is all IMO, YMMV etc


Article #61 is about the EGR system and is a good read about how it works, what it does and why it is in place.

Interesting article.

It doesn't really quite apply as the vehicle that's being used is a Camry, not a LC. The operation is slightly different as well, from my understanding the EGR is only open at cruising speeds, it's not a range of operation as it is in the Camry.

Additionally, Mr. T needs a quick and easy way to bypass the EGR system for vehicles that are sold without it (non-Cali spec). Producing a different ECU would be expensive, telling the ECU to ignore it when the temp sensor is bypassed would not be.

There is a CEL if the EGR is running too hot. So far, I have not managed to trip that CEL, despite bypassing the temp sensor. So the ECU must understand a difference between bypassing the temp sensor and the temp sensor running out of range (too hot).

 

[96r50]

Interesting article.

It doesn't really quite apply as the vehicle that's being used is a Camry, not a LC. The operation is slightly different as well, from my understanding the EGR is only open at cruising speeds, it's not a range of operation as it is in the Camry.

Additionally, Mr. T needs a quick and easy way to bypass the EGR system for vehicles that are sold without it (non-Cali spec). Producing a different ECU would be expensive, telling the ECU to ignore it when the temp sensor is bypassed would not be.

There is a CEL if the EGR is running too hot. So far, I have not managed to trip that CEL, despite bypassing the temp sensor. So the ECU must understand a difference between bypassing the temp sensor and the temp sensor running out of range (too hot).

Just to clarify, in #61 the example of a diagnostic procedure starting on the middle of page 6 is for vehicles not equipped with an EGR temp sensor (the example used is a 95 Camry); the first 5 pages are about EGR systems in general and diagnostics of an EGR temp sensor equipped vehicle, and as I understand it, does apply to our trucks.

Which CEL are you referring to (EGR running too hot)? P0401 is "EGR temp sensor value does not exceed 38C (100F) above ambient air temperature". P0402 is "EGR temp sensor value is high during EGR cut-off when engine is cold". As far as I can tell there isn't a CEL for the EGR temp being too high during normal operation with the engine at operating temperature.

I agree that Mr T may have put something in place for non EGR equipped trucks, and I think you may have found it. I'm not trying to sandbag your mod, I just want to help make sure all the bases are covered. With that said, you have a PM coming, as I think I may be able to help some more!

 

[Ebag333]

Which CEL are you referring to (EGR running too hot)? P0401 is "EGR temp sensor value does not exceed 38C (100F) above ambient air temperature". P0402 is "EGR temp sensor value is high during EGR cut-off when engine is cold". As far as I can tell there isn't a CEL for the EGR temp being too high during normal operation with the engine at operating temperature.

Well, according to the FSM, the codes are:

P0401
Exhaust Gas Recirculation Flow Insufficient Detected

P0402
Exhaust Gas Recirculation Flow Excessive Detected


The wording of it lead me to believe that it would detect excessive flow (IE: too warm) at any point, not just when the engine is cold.

Some of the triggers for this are:
EGR valve stuck open
EGR VSV open malfunction
Open in VSV circuit for EGR
Short in EGR gas temp. sensor circuit
ECM

Several of these I would imagine would happen even when the engine was hot.

For the P0402 code, there is a note in one of the Technical Training guides that says that it is only checked when the Throttle Position is 9 to 14.7. I'm not familiar with what those translate to in laymans terms.


Here's a chunk of that document, I'll link to the whole thing at the bottom:

EGR Temperature Detection Method
This method is used on the VSV Cut-off Control EGR System. An EGR
temperature sensor is installed in the EGR passageway. During normal
EGR flow, the temperature of the EGR temperature sensor will rise at
least 35°C (95°F) above ambient air temperature.

P0401 Insufficient Flow
When the EGR valve is open, the ECM compares EGR temperature to
intake air temperature. If the temperature does not rise a specified
amount over ambient temperature, the ECM assumes there is a problem
in the system, and this information is stored in the ECM. If the problem
occurs on the second trip, DTC P0401 will set and the MIL will turn on.

P0402 Excessive Flow
When the EGR is off, the ECM measures EGR temperature. If the EGR is
open, the EGR temperature will be higher than expected. If the problem
occurs on the second trip, DTC P0402 will set and the MIL will turn on.

The doc also talks about EGR MAP Detection Method and EGR Valve Position/
Temperature Detection Method, neither of which I believe our trucks use.


TOYOTA Technical Training - Exhaust Gas Recirculation (EGR) System Diagnosis

 

[alaskacruiser]

Also, I just stopped by my local Toyota dealer and they said the part listed (82824-35020) is not available anywhere. Can anyone confirm this? I need to contact CDan, I know...

I would think they should be able to order it. It might need to come from Japan though if they did. I think Mot looked into it and was told that they could make more if someone ordered some.

Just asked cruiserdan about this part and he says it comes up as an invalid part #. Does someone on mud have a stash of these somewhere, or should I try Mot?

 

[Ebag333]

I ordered it through my local dealer, which is staffed by folks who will order you the right part if you give them the exact part number. Shouldn't be an invalid part number, unless Mr. T is not making it anymore.

You could just use a piece of wire or paper clip to bypass as well.

 

[kup99]

I will try and post up the easy way today after work.


Lookin forward to it!! Thanks again in advance!!

 

[kup99]

bump!

 

[alaskacruiser]

I ordered it through my local dealer, which is staffed by folks who will order you the right part if you give them the exact part number. Shouldn't be an invalid part number, unless Mr. T is not making it anymore.

You could just use a piece of wire or paper clip to bypass as well.

Just checked with Lithia Toyota of Medford, and hey confirmed this part is not available anywhere, as CDan said. I would like to obtain this part instead of going the paper-clip route so that I can maintain a factory look for emissions inspections. If anyone has this part they are willing to sell me (Toyota part #: 82824-35020) or knows where I can get it, please PM me.

 

[Ebag333]

I have one.


But it's going on the truck.
(Tonight! Since today's the first day it hasn't been rainy or cold in a while.)

 

[alia176]

Just checked with Lithia Toyota of Medford, and hey confirmed this part is not available anywhere, as CDan said. I would like to obtain this part instead of going the paper-clip route so that I can maintain a factory look for emissions inspections. If anyone has this part they are willing to sell me (Toyota part #: 82824-35020) or knows where I can get it, please PM me.

Factory look for emission - since you'll have a connector hanging out in mid air, won't this raise suspicions with the emission guy?