CEL codes and ultrasonic cleaning

[landcruiser3DP]

just sent off an oil sample to blackstone because i didn’t read the head gasket threads as pre-purchase “due diligence” and listened to the local land cruiser whisperer and didn’t do a light test on the head gasket.

anyway.

this vehicle was throwing a p0110 coolant temp code and a p0172 banks too rich pre-purchase.

i read up, opened the mass air flow sensor, looked at it, then put it back on and tightened the hose clamp - which /seemed/ loose but in thinking about it since i just took everything apart why wouldn’t it be - and put it back together.

so ran it to o’rielly’s and they tell me it is /only/ reading p0401 (which i would be sure about if i could find where i wrote this down). anyway, i think this is an EGR valve code (or something close by).

0. is there a sticky on CEL code readers and/or how/when/why to clear CEL codes?
1. on the mark with cleaning the EGR etc for this code?
2. any rock solid feedback on if or can i put parts in an quality ultrasonic cleaner (that i got cheap)? i’m under the impression that the “cavitation” in an ultrasonic cleaner is not a problem for electrical parts and last and some folks just use dishwasher soap and water for the medium.
3. is there a short list of easily accessible parts i can clean and maybe harder to get at parts i can clean like this?
4. or is there a bullet list of what to clean with what if you want to make an afternoon of it?

i’ll search now to see if i can find anything. i’ve already got a lot of specific info on specific parts i need to organize.

THANKS

 

[Qball]

Wait what are you asking again? What can you clean with ultrasonic cleaner? Why? You have jewelry on your 80? Some simple cleaner usually works fine.

172 is oxygen sensor so take them out for a good cleaning with wire brush or better get a set of new O2s.

401 is ERG and replace all vacuum lines and ERG valve with OEM first then other if needed but it is usually the valve.

Coolant temp is coolant temp and follow the many overheating thread here and start with TStat, coolant flush and fan clutch.

 

[landcruiser3DP]

Wait what are you asking again? What can you clean with ultrasonic cleaner? Why? You have jewelry on your 80? Some simple cleaner usually works fine.

172 is oxygen sensor so take them out for a good cleaning with wire brush or better get a set of new O2s.

401 is ERG and replace all vacuum lines and ERG valve with OEM first then other if needed but it is usually the valve.

Coolant temp is coolant temp and follow the many overheating thread here and start with TStat, coolant flush and fan clutch.

thanks. yeah. what can i clean with an ultrasonic cleaner. i clean the carbs on my bike with it. seems to work well.

so new O2 sensor and new EGR valve for starters?

THANKS and goodwill

jon

 

[landcruiser3DP]

Wait what are you asking again? What can you clean with ultrasonic cleaner? Why? You have jewelry on your 80? Some simple cleaner usually works fine.

172 is oxygen sensor so take them out for a good cleaning with wire brush or better get a set of new O2s.

401 is ERG and replace all vacuum lines and ERG valve with OEM first then other if needed but it is usually the valve.

Coolant temp is coolant temp and follow the many overheating thread here and start with TStat, coolant flush and fan clutch.

arg. re-reading here. skip the coolant flush, tStat and fan clutch if you think you need to do a radiator and do them when you do the radiator? or go ahead and do the tStat now?

i’ve got lots of info but putting it together sensibly and seeing if i can tackle it myself is another matter.

also, in order of - “i’d do it while you are in there” - the task list is basically:

1. valve gasket and assorted sundries and then,

2. head gasket and assorted sundries?

and if i do the head gasket (somehow) i am doing the work associated with the valve cover gasket is that right?

thanks.

 

[Qball]

thanks. yeah. what can i clean with an ultrasonic cleaner. i clean the carbs on my bike with it. seems to work well.

so new O2 sensor and new EGR valve for starters?

THANKS and goodwill

jon

Wow you much have a really big ultrasonic cleaner. If it’s that big then the whole intake plenum! Then maybe injectors? But some say it’s best not to mess with them.

New O2 will never hurt and might get you a little better performance and MPG.

I would do the entire coolant system , granted I always have someone do that for me as I don’t want to deal with the coolant.

New ERG and vacuum hoses will always be needed.

 

[landcruiser3DP]

thanks a lot Qball.

i’m trying to see if i can organize work intelligently based on my skills. also i work in the street so there’s that for me to consider.

right now order of priority is inspection sticker, heater valve and hoses, and radiator. the radiator hoses are new.

if blackstone comes back with bad news about the HG i will have to find some help and rent some garage space for a month or something.

some follow up questions? maybe you or someone else can assist?

“intake plenum” is the same as “intake manifold”?

PCV valve i need to do because i think it is related to the CEL code. also EGR. but i wonder if i can ultrasonicaly clean that. or the MAF sensor if it will fit? or the intake hose? or other items that i can take off easily.

can i please ask how hard the fuel injectors are to get at?

if head gasket work is not needed i would try to fix the p0401 code but if that would be easier by doing a valve gasket then i want to try to organize the work around also doing the valve gasket.

but if there is other work like PCV valve, EGR or others that are easy to do one by one then i will just start and order those parts and tackle them piecemeal.

THANKS for this and any more intel

jon

 

[Tools R Us]

So, you are firmly in the "if it's not broke, keep fixing it till it is" camp?

Have fought many P0401/402 codes and have never seen a bad EGR valve on a 1FZ. In most cases, just put a 4.7K ohm resister across the sensor connection, no more code.

Have run lots of stuff through the ultrasonic (cheap Harbor Freight) with good success. Somethings should not get wet, but other than that... We run it with a little water based de-greaser or dish soap in the water, some works better than others, some is hard on plating, etc. Beats cleaning hardware by hand.

 

[landcruiser3DP]

So, you are firmly in the "if it's not broke, keep fixing it till it is" camp?

Have fought many P0401/402 codes and have never seen a bad EGR valve on a 1FZ. In most cases, just put a 4.7K ohm resister across the sensor connection, no more code.

Have run lots of stuff through the ultrasonic (cheap Harbor Freight) with good success. Somethings should not get wet, but other than that... We run it with a little water based de-greaser or dish soap in the water, some works better than others, some is hard on plating, etc. Beats cleaning hardware by hand.

thanks man. apologies for the posts. we all start somewhere.

i only want to work on something if it is worthwhile. if it is best to buy a new part i’m happy doing that. would like to plan it strategically though and get my ducks in a row before winter hits. the ultrasonic is nice and i saw some info about carbon breaking loose and fouling a sensor that will throw a code.

if i see p0401 on o’rielly’s obd II and they say that is all there is is it possible there are other codes and the guy isn’t using it correctly? anything is possible with obd II i guess? or better get a device or two and learn to use them?!

also can i ask you if there is a thread for 4.7K ohm resistor? i’m getting better with elektrikery. but i’ve been researching the codes associated with the two errors that supposedly went away and i only ran across this EGR/p0401 issue thead (if i’m correct about that) from reading links off the FAQ links...

THANKS

 

[Tools R Us]

There are tons of threads about P0401/402 codes, include resister in the search and it's likely to come up, common fix.

Best to have your own OBD2 reader, so you know what is going on. There are lots of them, my favorite, UltraGauge OBDII Scan tool and Information Center

 

[landcruiser3DP]

So, you are firmly in the "if it's not broke, keep fixing it till it is" camp?

Have fought many P0401/402 codes and have never seen a bad EGR valve on a 1FZ. In most cases, just put a 4.7K ohm resister across the sensor connection, no more code.

Have run lots of stuff through the ultrasonic (cheap Harbor Freight) with good success. Somethings should not get wet, but other than that... We run it with a little water based de-greaser or dish soap in the water, some works better than others, some is hard on plating, etc. Beats cleaning hardware by hand.

hey @Tools R Us
can i also ask you about the throttle body sensor? i am going to crack open the LC FSM i got here yesterday. this seems like a good item for the ultrasonic?
can i get a list together of what i am cleaning or replacing if i want to get in and clean the throttle body? seems like a good PM item for the p0401 code? PSV valve is cheap and easy to do? hand clean the EGR. replace some hoses or inspect them for leaks?
THANK YOU

 

[landcruiser3DP]

There are tons of threads about P0401/402 codes, include resister in the search and it's likely to come up, common fix.

Best to have your own OBD2 reader, so you know what is going on. There are lots of them, my favorite, UltraGauge OBDII Scan tool and Information Center

thanks a ton. i’ll get one of those and keep moving forward. probably the wires one if it is reasonable i guess...

 

[ajax1]

It’s a land cruiser not a airplane, toss the ultra sconic cleaner, being obd2 you need to do the resistor trick or fix what is messing up in the EGR System, there is a test you can do layed out in the fsm.
Why did you read two different codes then what oreily read?

 

[Tools R Us]

In most cases, the P0401 code root cause is the modulator. When the diaphragm is perforated, exhaust goes into the vacuum system, clogging the lines, VSV, etc. I prefer to disable by blocking the vacuum, abandon the system in place and add the resister to kill the codes.

 

[landcruiser3DP]

It’s a land cruiser not a airplane, toss the ultra sconic cleaner, being obd2 you need to do the resistor trick or fix what is messing up in the EGR System, there is a test you can do layed out in the fsm.
Why did you read two different codes then what oreily read?

thanks man. i’m learning here and trying to get up to speed but it is a steepish learning curve.
on pre-purchase inspection it was throwing p0110 and p0172 but the mechanic and i seemed to think it was not a big problem so i negotiated and bought it.
i opened up the air filter cover, MAF sensor, looked in and tightened up the intake air flow hose clamp.

then rolled out to o’rielly’s for an obd II code reader and eve guy shows me only the p0401 code and says there is nothing else.

i guess i need to get my own reader.

trying to organize a plan of attack and educate myself at the same time. some of this work does not make sense to pay for at a mechanic. some i probably don’t want to pay for and want to learn to do. some i may need to bite the bullet on.

still trying to assess what i have.

 

[Qball]

In most cases, the P0401 code root cause is the modulator. When the diaphragm is perforated, exhaust goes into the vacuum system, clogging the lines, VSV, etc. I prefer to disable by blocking the vacuum, abandon the system in place and add the resister to kill the codes.

Ah I meant the modulator not the valve! Sorry, got those two mixed up, make sure to use OEM modulator.

 

[Qball]

arg. re-reading here. skip the coolant flush, tStat and fan clutch if you think you need to do a radiator and do them when you do the radiator? or go ahead and do the tStat now?

i’ve got lots of info but putting it together sensibly and seeing if i can tackle it myself is another matter.

also, in order of - “i’d do it while you are in there” - the task list is basically:

1. valve gasket and assorted sundries and then,

2. head gasket and assorted sundries?

and if i do the head gasket (somehow) i am doing the work associated with the valve cover gasket is that right?

thanks.

Have you simply tighten the valve cover bolts? Some of mine where hand tight/loose when I got mine. It also works well as automatic rust prevention system.

Why do you need to do the head gasket? Is it bad? I would not fix something until it needs fixing, I don’t believe that’s one of the PM items.

 

[landcruiser3DP]

Have you simply tighten the valve cover bolts? Some of mine where hand tight/loose when I got mine. It also works well as automatic rust prevention system.

Why do you need to do the head gasket? Is it bad? I would not fix something until it needs fixing, I don’t believe that’s one of the PM items.

thanks a lot Qball. i really appreciate the help. TRU mentioned “modulator” and i was going to try to find it in the stack of forum threads here and search the forums for it.

<edit: EGR Vacuum Modulator. /great/ thread by cahill here: PO401 and EGR/air intake manifold with pictures >

can i ask you what general vicinity this thing is in or if there is another name either it like fuel modulator or air modulator or something. i don’t remember running across the term in my research.

on the HG. i got a tad freaked reading the head gasket threads. the vehicle was in pretty good shape but i rescued it from a lady that had it eight months and managed to cap the heater control valve hoses and park it basically. plus the radiator seems to be leaking. so i wanted to try to organize my efforts.

if i do a valve cover gasket i want to do the VSV, or EGR or PCV or whatever is /easier/ to do while doing valve cover gasket. but what i can do now i’m an hour or two i’d also like to do while i order radiator parts.

then if word comes back i need to do the HG i want to fold in whatever i have listed for the valve cover gasket into that work i think(?).

but if i need to do HG i need to rent garage space locally for the month or find someone where i can stash it and work on it.

 

[landcruiser3DP]

In most cases, the P0401 code root cause is the modulator. When the diaphragm is perforated, exhaust goes into the vacuum system, clogging the lines, VSV, etc. I prefer to disable by blocking the vacuum, abandon the system in place and add the resister to kill the codes.

TrU,
can pull the throttle body off easily (?) and ultrasonically clean that as an independent job?
and is cleaning the intake manifold a larger job? or can i pull that and put it in a big bucket of soapy water and have at it?
and/or is it best to do the intake manifold if i do a head valve gasket or head gasket?
thanks...

 

[LC4LIFE]

A solution and some additional reading here - EGR Temp Sensor Test Plug

 

[landcruiser3DP]

There are tons of threads about P0401/402 codes, include resister in the search and it's likely to come up, common fix.

Best to have your own OBD2 reader, so you know what is going on. There are lots of them, my favorite, UltraGauge OBDII Scan tool and Information Center

MX over the EM plus v1.2 for a couple extra bucks i gather?
talking to support but i am not sure if there are any specific considerations to the lexus/LC.

UltraGauge EM Plus v1.2 [UltraGauge_EM_Plus v1.2_15] - $79.95 : UltraGauge, OBD II Scan Tool & Information Center

UltraGauge MX [UltraGauge_MX_1.3] - $89.95 : UltraGauge, OBD II Scan Tool & Information Center