06 lr3 trouble codes

jgdisco2

Well-known member
Feb 24, 2006
888
21
Goldsboro, NC
hey guys, drove the LR3(141K) to raleigh yesterday and got the CEL. it also stalled on us while in idle and intermittently runs a little rougher than normal.
here are the codes
P0175
p0174
p0101
p0171
p0172

those are all lean or rich codes and then a mass air flow sensor. should i just try cleaning the MAF or is it dying and needs replaced? anyone had all these codes grouped together?
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
Those are lean and rich codes which is odd to have at the same time. Usually P0101 is set because of the throttle body being dirty. I would start with cleaning that, as well as running some BG44k or other injector cleaner through the fuel system. MAFS failures aren't super common, but it can happen. I have definitely seen a dirty throttle body cause stalling.
 

jafir

Well-known member
May 4, 2011
1,628
0
Northwest Arkansas
I cleaned my throttle body a month or so ago. It made a world of difference in idle quality and throttle response. Before I cleaned it, it would surge in park and the would kind of lunge when taking off from a stop. That's all better now.

Today I ran a can of BG 210 and then dumped some BG44K in the tank. Throttle response is even better. (or so I think... it could be placebo I guess). I did reset the trip computer and on my test drive I was getting 22MPG. (I expect that to go down with some stop and go on the way to work tomorrow).

The MAF on these is the same as a bunch of Toyotas.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I think once you get a fuel trim fault with the light on, you need to reset the adaptions.

Here's a good example of what I'm talking about. I lift the dipstick up out of the tube so oil doesn't back up in the valve cover when I'm filling it. If I forget to push that thing back down it will flag a lean fault. If I just clear the codes the car will go less than a mile and the light will be back on again. Even though I have fixed the vacuum leak by pushing the dipstick back into the tube. I have to reset the adaptions to make the code stop being flagged.
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
I think once you get a fuel trim fault with the light on, you need to reset the adaptions.

Here's a good example of what I'm talking about. I lift the dipstick up out of the tube so oil doesn't back up in the valve cover when I'm filling it. If I forget to push that thing back down it will flag a lean fault. If I just clear the codes the car will go less than a mile and the light will be back on again. Even though I have fixed the vacuum leak by pushing the dipstick back into the tube. I have to reset the adaptions to make the code stop being flagged.

But also for that at-home mechanic, the lean faults should eventually clear themselves if it has actually been fixed.
 

stu454

Well-known member
Dec 15, 2004
5,407
61
Atlanta, GA
I have an occasional lean code. I suspect it was due to some shitty gas on my Utah trip. How do I reset adaptations?
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
hey guys, drove the LR3(141K) to raleigh yesterday and got the CEL. it also stalled on us while in idle and intermittently runs a little rougher than normal.
here are the codes
P0175
p0174
p0101
p0171
p0172

those are all lean or rich codes and then a mass air flow sensor. should i just try cleaning the MAF or is it dying and needs replaced? anyone had all these codes grouped together?

If you clear the codes out of this thing and again get both lean and rich faults stored that would be really odd. I would smoke test it for leaks and flush the injectors. You could run some BG 44K thru the tank to clean them slowly and cheaper. The lean faults we see all the time, its the rich faults added in that make no sense. Maybe check the voltage drop across the ground circuit. Like from Battery neg post to the block while someone cranks it. Pull the fuel pump fuse and wait for it to stall,then have someone crank it while you measure the voltage drop from neg post to the block. It should be less than .3 of a volt. If you have 1 volt of drop it's way to much. I've been seeing them with 3 or more volts of drop lately. You have a ground strap in the right front wheel well that goes from body to frame to engine. That guy rots out and usually causes a no crank at times. But I see it cause a lot of strange shit.
 

jgdisco2

Well-known member
Feb 24, 2006
888
21
Goldsboro, NC
Update: ran a can of bg 44 through the truck, maf cleaned as well as throttle body. CEL came back on after 30 or so miles. Codes are lean now P0171, P0174. Both banks are lean now. Intake gasket my next questionable possibility? Oxygen sensor?
 

jgdisco2

Well-known member
Feb 24, 2006
888
21
Goldsboro, NC
P0101, P0172, P01075 have shown back up. Running really rough at low speed and idle, feels like it's "coughing" and isn't very responsive.
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
It is interesting that you get a P0101 after cleaning the throttle body, I've never seen that fault caused by anything else. Maybe you do in fact have a bad mass air flow sensor.
 

jafir

Well-known member
May 4, 2011
1,628
0
Northwest Arkansas
Could a P2098 also be the adaptive values or is it usually something else, like a bad cat?

I was getting a lean code or something from one of the upstream O2 sensors, and I think it was from someone welding in a cat and damaging the sensor. I replaced the sensors (all 4) and now the only code I get is P2098.
 

kels83

New member
Jan 3, 2017
4
0
Austin, TX
Adding some advise after i had lean codes both banks. Fixed a couple leaks... added gasket maker to both EGR gaskets + tightened bolts on the back side of the EGR return tube. I guess 10+ years of exhaust vibrations loosened those EGR bolts.

Codes came back, Crap. My GAP IID tool reads fuel trim so watched some YouTube videos and was running ~+15 combined short plus long term trims. I read in jymmiejamz post above above on this thread to reset the engine adaptation values, so I did this with the GAP tool too. It IMMEDIATELY lowered both fuel trims to ~1%+-. It's only been a couple days but the engine adaptation values were part of my problem. The code hasn't returned yet! BIG THANK YOU!

I bet this is why many people report the lean codes will "go away" after a couple weeks of driving. I was hoping for an immediate fix to pass inspection, but the adaptation algorithms may prevent this for lean codes P0174 and P0171.
 
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jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
Just to be clear, the adaptive values always start at 0. As you drive the vehicle will adjust the fuel trim as needed. If you reset the adaptions without doing a repair the faults will come back after a few drive cycles (or more if the issue isn't that bad).
 

kels83

New member
Jan 3, 2017
4
0
Austin, TX
Just to be clear, the adaptive values always start at 0. As you drive the vehicle will adjust the fuel trim as needed. If you reset the adaptions without doing a repair the faults will come back after a few drive cycles (or more if the issue isn't that bad).


Thanks for the additional info, the codes have not come back yet, but I can't pass inspection in Texas because the "catalyst" and "evaporator" sensors show a status of "not ready". My GAP IID tool doesn't have any sensors with those names. I bet it's a matter of getting through some drive cycles, and I've put on about 50 miles during about 10 short trips. There is some published info on D2 drive cycles, but I can't find anything on the LR3/DISCO3. Any ideas?