Freaking P0125
Thread Starter
Pole Position
Joined: Mar 2007
Posts: 362
Likes: 2
From: Moscow, Russia
Freaking P0125
I am at loss. The most annoying P0125 won't go away even if I clear while driving. Occasional/pending P0171 (system too lean). MPG is between 5 and 12 for 10-mile average. Both A/F sensors (before catalytic conv-r) are new (checked them several times). Borrowed a remanufactured MAF sensor from Autozone. Solved nothing. I guess there is a vacuum leak somewhere, or misplaced vacuum lines after engine swap, but I cannot find it.
CL Community Team
Joined: Apr 2004
Posts: 17,337
Likes: 213
From: Miami, Florida
Yeah Home Depot has those hoses. I just sometimes use some duct tape as a temporary fix and to test.
The P0171 is an accompanying error, the P0125 is the one to focus on. If a mechanic near you has an advanced OBDII scanner they could see the readings coming off the banks and that could help narrow down where the problem lies.
The P0171 is an accompanying error, the P0125 is the one to focus on. If a mechanic near you has an advanced OBDII scanner they could see the readings coming off the banks and that could help narrow down where the problem lies.
Thread Starter
Pole Position
Joined: Mar 2007
Posts: 362
Likes: 2
From: Moscow, Russia
Yeah Home Depot has those hoses. I just sometimes use some duct tape as a temporary fix and to test.
The P0171 is an accompanying error, the P0125 is the one to focus on. If a mechanic near you has an advanced OBDII scanner they could see the readings coming off the banks and that could help narrow down where the problem lies.
The P0171 is an accompanying error, the P0125 is the one to focus on. If a mechanic near you has an advanced OBDII scanner they could see the readings coming off the banks and that could help narrow down where the problem lies.
Thread Starter
Pole Position
Joined: Mar 2007
Posts: 362
Likes: 2
From: Moscow, Russia
Thread Starter
Pole Position
Joined: Mar 2007
Posts: 362
Likes: 2
From: Moscow, Russia
Ok, fixed that hose. Now my RX has part of Kitchen Sink Spay Hose :-) P0125 still continuing coming back. Among with pending P0171, P1135, and P1155. I am absolutely sure that A/F Heaters are Ok. The resistance on them measures 1.0 Ohm. Maybe something with wires. I will check again from ECM harness. Can it be that third unheated O2 sensor behind catalytic parts?
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CL Community Team
Joined: Apr 2004
Posts: 17,337
Likes: 213
From: Miami, Florida
The two things that stick out to me are a leak/crack, even small one or something somwhere that is just not tight. 1130 is related to the one behind the engine and 1150 is on the front. Since it is both, to me this suggests something perhaps with the either the fuel delivery BEFORE reaching the engine and/or the air intake system, even though effects of combustion are what the engine is looking for.
I know your engine was overhauled, but even gas sitting in the tank for a bit and then having the vehicle restarted can cause some issues. I went on a trip to Jamaica for a week, came back and my RX started up like $@%#.
With the air intake, one of my pet peeves was always that the stock airbox was never truly tight and hot engine air was going to sneak in through gaps in the grooves (I used to wrap it in duct tape).
CL Community Team
Joined: Apr 2004
Posts: 17,337
Likes: 213
From: Miami, Florida
I am about to go to my track, but as I thought about this a little more, I am placing a little more emphasis on the volume of air you are getting into your engine as I noticed your MPG.
Thread Starter
Pole Position
Joined: Mar 2007
Posts: 362
Likes: 2
From: Moscow, Russia
Lexus manuals specify Heater Coil Resistance to be 11 to 16 Ohms. My new Denso sensors had resistance of 1 Ohm. I bought them off Ebay for $100 each. They've been in unopened Toyota factory packaging. Does Denso provide any kind of direct warranty? Very strange. I am thinking to try those Bosch sensors from O'Reilly, they have them for $179.99 each.
CL Community Team
Joined: Apr 2004
Posts: 17,337
Likes: 213
From: Miami, Florida
I would stick to the Densos though. I don't have an ohmmeter handy (I should) so that I could check mine to see what is up.
The damn manuals are full of errors. A few weeks go Fern uncovered an error with ATF fluid levels between the owner's manual and service manual.
Unbelievable.
The damn manuals are full of errors. A few weeks go Fern uncovered an error with ATF fluid levels between the owner's manual and service manual.
Unbelievable.
Lexus Champion
Joined: Jan 2005
Posts: 2,447
Likes: 9
From: CA
I just replaced the bad A/F sensor with a Denso one bought at rockauto.com for $160 shipped. CEL code was P1130 and P1135, with P0171 and P0172 accompanying the bad sensor. So far after I clear the code, it has not come back. Bosch made a mistake a while back (labeling a o2 sensor as a A/F sensor), it sources from Denso so why bothers getting Denso second handed.
