davecich

I have the four errors codes listed above. Can someone help me with:

1-So they all point to the same issue?
2-What may that issue be? which sensor to start with?

P1153-fuel control shifted lean
p1154-fuel control shifted rich
p0125-the PCM has determined the amount of time it took for the coolent temperature sensor to reach an input value consistant with closed loop operation was too excesive. (Stuck thermastat?)
P0171

VVT-i

You man need to start with cleaning out the mass air flow meter located on top of the air filter box. If you got the scan tool handy and you can look at the Data please take note at the short term and long term fuel trim.
The total # of the short term and long term fuel trim should be close to +/- 0.

For example the scan tool will shows:

Short term fuel trim bank 1=+9%
Long term fuel trim bank 1 = -8%
Total fuel trim bank 1 = +1%
This is o.k and normal operation. If you see the total # of +40%(example) your air flow meter or AF sensor not doing their job.

I would try to clean the mass air flow first.

P0125 always come on when one of the A/F sensor goes bad,but just cross your finger that its only the MAF.

Good luck

davecich

I have cleaned the MAF with no change twice in the past. Thinking about buying a new one and returning if it does not fix things. Is this a good idea, or should I start looking at o2's?

ben

Lexmex

As my good colleague mentioned the P0125 is an accompanying error here. Actually, the P0171 would also be.

I am going to assume that you reset the CELs and they still came up.

A dirty/malfunctioning MAF is the first place, reason being is that this is the first place in the chain of the Air (MAF)/Fuel (A/F or O2 Sensor) ratio. When you cleaned the MAF did you clean the red diode and the small threads inside?

Now, the other codes, 1153 and 1154 point to A/F sensors, the other end of the equation. More often than failure, the readings from them were out of bounds so to speak and so they light up a CEL.

Before you go spend cash on parts, the best thing in this situation is as VVT-i mentioned to get your hands on advanced OBDII scanner. These read the readings off the MAF (as he mentioned above) and also the readings off both banks of A/F sensors. You don't need to go to Lexus or Toyota for this and a lot general mechanics have this type of scanner (I don't think AutoZone has it offhand, just the one to check the codes).

There really isn't a magic trick to know otherwise, without buying parts and changing things out, exactly where the specific problems lies, with MAF or A/F sensors or something else (ECM is a very, very remote possibility along with throttle body opening/closing issues)

Meetya

Come on guys! P1153 with P0125 and P0171 means top A/F sensor on bank 2 (front) is malfunctioning. Just replace it. Cleaning MAF is a good idea however in this case MAF is not the culprit.
Also I bet it is P1155 not P1154. Davecich, did you mistype?

davecich

Ok, I wiped error codes out and checked them later in the day.

The codes are 0125/1153/1155 and Po44o. For kicks and giggles, I changed MAF, no fix. I am thinking of changing o2 sensor on manifold, as Meeta recomends. I tried finding the advanced scanner at a couple of chain shops, no go.

What do you all think?

Dave

davecich

ps-it used to be code 1154, have slip in front of me. Six codes came up in all.

1153 and 1155 twice, a light error, a missfire.

Lexmex

Was it a misfire, did you feel something, because there would be some other codes that would fire up.

That P0440 is an interesting one, evaporative emission control system. That gets triggered when your fuel tank pressure=atmospheric pressure 20 minutes after the vehicle is started.

That can of course be a gas cap issue (try taking it off and putting it back on) there is a laundry list of other things, but deal with the one in the next paragraph.

However, the other codes point strictly to what meetya mentioned because both P1153/1155 are Bank 2 Sensor 1, this little A/F sensor conveniently located on the front manifold. Note I have had some welding done, so take a look to see if you have any cracks around there.

lexusrx300

I had a tough to track down code that was engine coolant temp and tricked off many others including misfires... I'd check the air flow sensor located on in side of the engine. Not the MAF on the intake.

Meetya

You mean IACV (Idle Air Control Valve)? Nah, it has nothing to do with it.

P0125 has nothing to do with coolant temperature sensor. As well as P0171 and P0172, in 99% P0125 is an accompanying code with one or more of P1133, P1135, P1153, and P1155.
https://www.clublexus.com/forums/sho...ighlight=P0125

Meetya

1. Go to Walmart, buy a an Ohmmeter. Keep the receipt.
2. On the parking lot of Walmart. Pop the hood, disconnect the front sensor connector.
3. Connector of that sensor has 4 contacts, 2 are silver (sensor heater) and 2 are gold (output). Read the resistance of between 2 silver contacts.
4. It should read around 1 Ohm +- 0.3, depending on temperature of the engine.
5. If it is short (0 Ohms) or open (infinite Ohms). You have to replace that sensor.