Error Codes P0100, P0110 & P0171 Point To Any One Thing?

[PK_3]

I have the above trouble codes on 99 Rx300 My OBC reader identifies these as, I wondering if the indicate 3 problems or all point to one. Also, what that problem or problems might be

P0071: System too lean bank 1

P0100: Mass or volume air flow circulation malfunction

P0110: Intake air temp (AT) circuit malfunction

Recently the smog test center had given me P0101 (I think), I cleaned MAF (which did not appear particularly dirty or damaged). The CEL came back on and I got the code above codes.

(Don,'t know weather this has anything to do with anything but according to my OBCII software there are some zero voltages of “0v.” on 2 of 3 “sensor short term fuel)

Regards, PK

[blk_on_blk]

Did you check to see if any of the intake duct work is dislodge or cracked? I would think these codes would tie in with an intake air delivery issue, and if you are getting a leak somewhere, you'll get odd readings in your MAF, could end up with too much air making it lean in bank 1, and the air temperature could be reading awry because of air coming in where it shouldn't.

First gut response is you've got an air intake leak somewhere, but i could be wrong.

[smooth1]

Sounds to me like you might need a new MAF as the IAT is part of it. Are you sure you reconnected it correctly and firmly? How did you clean the MAF? what did you use? Those elements are very sensative. Did you reinstall it correctly? Do you have any pics so we can take a look?

[PK_3]

Sounds to me like you might need a new MAF as the IAT is part of it. Are you sure you reconnected it correctly and firmly? How did you clean the MAF? what did you use? Those elements are very sensative. Did you reinstall it correctly? Do you have any pics so we can take a look?

Hi,

Thanks for the reply.

I used a spray MAF cleaner specifically for MAFs. I didn't actually touch the element at all with anything but the spray which I let drip dry.

I did have some initial problems with the car “bucking” when I tried to drive it. I lubricated the MAF O-ring and the contacts contact grease...solved that problem. still have CEL.

Regards, PK

[smooth1]

I really think that either the MAF and IAT were reinstalled incorrectly, or are not working and need to be replaced.

[PK_3]

Did you check to see if any of the intake duct work is dislodge or cracked? I would think these codes would tie in with an intake air delivery issue, and if you are getting a leak somewhere, you'll get odd readings in your MAF, could end up with too much air making it lean in bank 1, and the air temperature could be reading awry because of air coming in where it shouldn't.

First gut response is you've got an air intake leak somewhere, but i could be wrong.

Hello,

Thanks. I did give the intake ducting a cursory once over, nothing obviouse. But didn't focus on it because of the “lean bank 1” descriptor which I interpreted to mean 1 row of cylinders. A leak in in central ducting I would have thought would give lean errors for both banks, 1 & 2.

But, I will give it a twice over, spray some starting fluid around any areas of suspicion...see if I get a blip out of the motor.

Regards, PK

[smooth1]

Did you check to see if any of the intake duct work is dislodge or cracked? I would think these codes would tie in with an intake air delivery issue, and if you are getting a leak somewhere, you'll get odd readings in your MAF, could end up with too much air making it lean in bank 1, and the air temperature could be reading awry because of air coming in where it shouldn't.

First gut response is you've got an air intake leak somewhere, but i could be wrong.

Hello,

Thanks. I did give the intake ducting a cursory once over, nothing obviouse. But didn't focus on it because of the "lean bank 1" descriptor which I interpreted to mean 1 row of cylinders. A leak in in central ducting I would have thought would give lean errors for both banks, 1 & 2.

But, I will give it a twice over, spray some starting fluid around any areas of suspicion...see if I get a blip out of the motor.

Regards, PK

Actually, it refers to the location of the sensor itself. Bank 1 sensor 1 is the exhaust sensor in the header after the cylinders. And it is just reading a lean condition. Which could be from a bad MAF, blocked air induction or PCV piping. It could mean a fuel pressure issue, or engine coolant temp sensor is bad, or a heated 02 sensor that went bad.

[PK_3]

I really think that either the MAF and IAT were reinstalled incorrectly, or are not working and need to be replaced.

Hi, Thanks again for your reply.

I'll probably trust your analysis but, is there any way to check MAF? Impedance or voltage whatever.? Also, wouldn't I have “to lean” on both banks, “1” and “2” in that they share the MAF & the IAT?

As for installation, the only thing not done by the book was replacing the O-ring, It seemed perfectly pliable with no deformation or nicks.

As to electrical connections, I did what has always worked for me. I cleaned mail and female connectors with a soft, brass wire brush and rinsed thoroughly with contact cleaner. An as always, plugged, gently jiggle and unplugged it several times.

The Icing on the cake was the electrical contact grease.

Thanks again for your input,

PK

[blk_on_blk]

You can check the MAF, but that requires supplying power to it, attaching a ground, hooking into the right terminals with a meter to measure the response (and then you need to know what you are looking for in the response), and lastly you'd need to blow air through it to get it to read. In short, it's a job for a skilled technician.

If I were you, I would go and see if I could find a used MAF at a junk yard (or through an on line used parts dealer or through eBay) and just put that in to see if it responds differently. That's probably cheaper than having a skilled tech look at it for an hour to diagnose the problem. Plus, if I recall right, Toyota uses the same MAF in many applications, so you may be able to find one out of a ES300 that works for a test (but I'd check on that to be sure).

[PK_3]

Hmm,

Getting power and a ground to it is no big feat, but I see your point, how much voltage or impedance for how much airflow and on which leads etc. is a lot of messing around.

I agree with you, turning it over to a $1xx.xx trade “tech” to twiddle around with is probably far more expensive than all the potential problem parts combined.

The car has 80k on it. Is this the normal life of a MAF? Are you fairly confident that all the error codes could just point to the MAF?

thanks again, PK

[smooth1]

To a point you have to remember this is a forum, I don't have your car in front of me. I can't look over the system, and inspect it for myself, plug in my ODBII scanner and take a look. I only have the info you have provided. But I can say for sure from what you have described above, that your issue is probably the MAF/IAT sensor, and or the 02 sensor.

[PK_3]

Actually, it refers to the location of the sensor itself. Bank 1 sensor 1 is the exhaust sensor in the header after the cylinders. And it is just reading a lean condition. Which could be from a bad MAF, blocked air induction or PCV piping. It could mean a fuel pressure issue, or engine coolant temp sensor is bad, or a heated 02 sensor that went bad.

O.K That makes sense. So the “bank 1” could indeed be a systemic air leak. An odd thing is that the numbers on the smog report were far below the max, but were pretty far above the mean (rich ?).

Thanks for the other tips. It would seem most likely a sensor problem (no?) MAF or 02 senor. The car runs absolutely fine and the temp gage doesn't indicate anything weird and at 80k in the suburbs, I wouldn't expect major blockage in the PVC or air intake but I'll check it out.

Thanks again, PK

[PK_3]

Hello again

To a point you have to remember this is a forum, I don't have your car in front of me.

Of course, and all I am looking for is some broad direction and possible Lexus specific idiosyncrasies which you have given me and more. I know ziltch about these cars and their quirks.

... I only have the info you have provided.

That's why I keep piling it on. It's not because I don't trust experience and judgment at all, I only want to give as much to work with as I can. I think I've done that and am content with your advice. Thank you.

... that your issue is probably the MAF/IAT sensor, and or the 02 sensor.

Then I'll run with that.

Regards, PK

[RX300Billy]

Sounds to me like you might need a new MAF as the IAT is part of it. Are you sure you reconnected it correctly and firmly? How did you clean the MAF? what did you use? Those elements are very sensative. Did you reinstall it correctly? Do you have any pics so we can take a look?

Hi,

Thanks for the reply.

I used a spray MAF cleaner specifically for MAFs. I didn't actually touch the element at all with anything but the spray which I let drip dry.

I did have some initial problems with the car “bucking” when I tried to drive it. I lubricated the MAF O-ring and the contacts contact grease...solved that problem. still have CEL.

Regards, PK

I also had a P0110 reading and removed the mass air flow meter, cleaned with carb/oxygen cleaner and reinstalled, and reset error code and car drives great. smooth. I read that dirty maf meters may cause my transmission to shift weird as my tranny was staying in 3rd gear and not shifting to the o.d. I hope the cleaning helps my tranny.

[RX300Billy]

Sounds to me like you might need a new MAF as the IAT is part of it. Are you sure you reconnected it correctly and firmly? How did you clean the MAF? what did you use? Those elements are very sensative. Did you reinstall it correctly? Do you have any pics so we can take a look?

Hi,

Thanks for the reply.

I used a spray MAF cleaner specifically for MAFs. I didn't actually touch the element at all with anything but the spray which I let drip dry.

I did have some initial problems with the car “bucking” when I tried to drive it. I lubricated the MAF O-ring and the contacts contact grease...solved that problem. still have CEL.

Regards, PK

I also had a P0110 reading and removed the mass air flow meter, cleaned with carb/oxygen cleaner and reinstalled, and reset error code and car drives great. smooth. I read that dirty maf meters may cause my transmission to shift weird as my tranny was staying in 3rd gear and not shifting to the o.d. I hope the cleaning helps my tranny.

RX300Billy