masco

Hello,

I'm a new addition to the forums, but I've been a long time lurker. Why did I sign up? My car is throwing a **** fit of codes. Here they are:

*drum roll please*

p0171 sys too lean bank 1
p0174 sys too lean bank 2
p0136 o2 sensor circuit bank 1 sensor 2
p1133 a/f sensor circuit response malfunction
p1153 a/f sensor circuit response malfunction

Lemme know what this combination of codes means.

Lexmex

Welcome to the Club.

Have you attempted to clear out these codes (either by scanner or pulling the battery cables off) and they still come up?

lexina

You don't want to clear the codes yet. The codes are there for reasons. There are a few things you want to look at with these codes from easy ones first to narrow down the problem. Does your engine iddle normal, or hesitate on excelleration? Does your car seem to consume more gas?
1. spark plugs
2. Coil packs
3. O2 sensors
4. Catalyst converter. I believe cat converter is 80k warranty or so.

code58

I agree Lexmex, the codes should be cleared, and then see what comes up.

masco

i've cleared the codes a few times. i have a code reader. [maxiscan ms409]

293000km's on the odo.

it's been a cycle. i clean out the maf, pull the efi fuse, it's all smooth and perfect at first. [not even any pending codes]. then it'll throw a coupel dtc's and the cel will turn on. then the a/f mixture slowly richens up until i get fed up and clean the maf/reset efi. when its at its worst it runs pig rich. black smoke rich. cloud of black smoke under a heavy load, wot.

admittedly i havent been cleaning the maf as well as i could. at first i was just cleaning the intake temp sensor. but i've figured out where the actual maf is and cleaned it throughly. hopefully this is all it needs.

the car has been dead repliable, its amazing. the car needs a full major service. maybe ill do the works on it if this doesnt work.

do you guys know if a maf from a rx330 is compatible with the rx300? cuz we have one of those too.

i havent thought about checking the sparkplugs. i've been so fixated on the lean condition meaning maf sensor. i'll check the plugs out, and fill you guys in tomorrow. thanks for the tip lexina.

Lexmex

The MAFs read slightly different since the engines are a bit different, but it might work in a pinch. I've used a Camry ignition coil (albeit modified) to work on my RX300 in Mexico.

Have you cleaned the IACV and the PCV valves?

Also, have you tossed in a fuel injection cleaner (Redline, Lucas or Amsoil's)

Reason I say that is the codes related to the A/F and O2 sensors are every single one of them.

P1153 is bank 2, sensor 1 right by the radiator (and visible in the engine bay)
P1133 is bank 1, sensor 2 and behind the engine block
P0136 is bank 1, sensor 2 and that is behind the main catalytic converter underneath the vehicle.

The P0171 and P0174 codes often accompany such a/f sensor issues and there could be a problem with fuel delivery.

masco

Turned out to be a dead o2 sensor @ 0.0v

Using a different MAF sensor seemed to make the car drive better. There's so many factors and variables that this wild goose chase had.

Highly recommend getting a o2 sensor socket, and a multimeter.

Thanks for you help!