Time for a riddle - 2001 IS300 - APPS - MAF - CATS!

SupraMario

SupraMario

I think it was the google
Mar 30, 2005
3,467
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The Farm
Back story, rebuilt motor at 149k, ran fine for around 8k miles, had issues with car around the 8k mark that pulled up CEL clogged cats. Car did the 25% power just hard pedal, no response etc.
Replaced cats, then car after 15ish miles would do the same thing, different code. P1121 (APPS) WTF? Pull over, reset battery, drive home. Does it again, this time without resetting battery, (with the car off) unplugged the MAF, thought this may be it, because car runs completely fine.
Throttle everything runs normal. I replace the MAF...drives fine to about 30 miles this time as I'm thinking I fixed it, Nope, this morning does it again, pull codes and it's a new list of codes, p1121 is not even in the list (thought my phone saved the list but it didn't, going to post them here soon).


So anyone like riddles, cause this one is driving me nuts...next step is to replace the ECM...it's $60 on ebay...ugg...it's the only thing I can think of at this point...

Anyone have any thought on this? Why does the car magically run fine (Minus the MAF being pulled part) with the MAF pulled?
 
hvyman

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
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Fullerton,CA
It have a electronic throttle.

With maf pulled your putting it a into limp mode or rather a seperate map where it uses the tps for input on how much fuel is to be added for x amount throttle.

Based off your code you shouldnt even be looking at the maf. Unplugging it is not a justifiable veryification for diagnoisis.

EDIT..
Here is a same problem thread on cl. I was trying to find the testing info but all the repair diag links are on my laptop at home.
http://www.clublexus.com/forums/per...ition-sensor-and-throttle-motor-problems.html
 
SupraMario

SupraMario

I think it was the google
Mar 30, 2005
3,467
6
38
38
The Farm
hvyman;2026321 said:
It have a electronic throttle.

With maf pulled your putting it a into limp mode or rather a seperate map where it uses the tps for input on how much fuel is to be added for x amount throttle.

Based off your code you shouldnt even be looking at the maf. Unplugging it is not a justifiable veryification for diagnoisis.

EDIT..
Here is a same problem thread on cl. I was trying to find the testing info but all the repair diag links are on my laptop at home.
http://www.clublexus.com/forums/per...ition-sensor-and-throttle-motor-problems.html
Click to expand...

I've read over all of those threads, I've got a Tb coming from a gs300 99 model to diagnose this further.
 
hvyman

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
12,568
1
0
Fullerton,CA
Not really any danger. Ecu just doesnt have all of its inputs.

I just wouldnt beat on it. Just cruise.
 
hvyman

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
12,568
1
0
Fullerton,CA
Ya but he also replaced those vacuum hoses himself and also replaced the tps sensor thinking it was the tps sensor. Seems more of human error than sensor error. and his code was different.
 
SupraMario

SupraMario

I think it was the google
Mar 30, 2005
3,467
6
38
38
The Farm
hvyman;2026360 said:
Ya but he also replaced those vacuum hoses himself and also replaced the tps sensor thinking it was the tps sensor. Seems more of human error than sensor error. and his code was different.
Click to expand...

I've got both 1121 and 1120
 
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