99 camry v6, code help

[casey38boost]

Here are the codes that where listed:

p0300

p0303

p0301

p1135

p1153

p0305

p0171



What do you think most likely is the culprit? I was thinking of replacing the front air / fuel sensor, closest to the radiator. Then go from there?

Maybe this a/f sensor is causing the misfire and rear bank to run lean?

[fenixus]

you have a random misfire and frequent misfires on all cylinders on rear bank (by firewall).
also both front & rear AFR sensors show problems (one is slow response and other has heater circuit problems).
due to both AFR sensors ECU is in fail safe mode.

did you run out of fuel recently until car died? it shows also P0171 - System Too Lean.

I would replace both AFR sensors with Denso OE fit first and reset the ECU.

[Yuko]

p0300 - Random misfire
p0301 - Misfire cylinder 1
p0303 - Misfire cylinder 3
p0305 - Misfire cylinder 5
p1135 - Air/Fuel Sensor Circuit Response. (Bank 1 Sensor 1)
p1153 - Air/Fuel Sensor Circuit Response. (Bank 1 Sensor 2)
p0171 - System to Lean (Bank 1)

I read online on another forum where a guy had a 98 ES300 (same engine and similar problem) he replaced the pre oxygen sensor with a new Denso one and fix it. I don't see how because the pre O2 sensor only read the air/fuel ratio and doesn't control it.

[casey38boost]

I am not sure if the car has run out of fuel, but I will check.

Should I clear the ECM and see what codes come back?

I would rather go one step at at time then replacing both front and rear o2 sensors if possible.

Thanks for the help

[fenixus]

Originally Posted by casey38boost

I am not sure if the car has run out of fuel, but I will check.

Should I clear the ECM and see what codes come back?

I would rather go one step at at time then replacing both front and rear o2 sensors if possible.

Thanks for the help

yeah, go ahead and clear codes first if you haven't already
most likely they all (maybe except P0171) return, some of them instantly if they persist, some others later (if still problem) as some of them require a 2 trip detection logic.

start with the rear bank AFR (bank 1 sensor 1), this one has a faulty heater most likely (reported heater circuit failure).
P1135 A/F Sensor Heater Circuit Malfunction (Bank 1 Sensor 1) (Only for California Spec.)

the one in front (bank 2 sensor 1) still works but reports a Response Malfunction (not good either; I was wrong above about Slow Response), qualifies for a replacement too.
P1153 A/F Sensor Circuit Response Malfunction (Bank 2 Sensor 1) (Only for California Spec.)

either of above codes drops the ECU into a limp (fail-safe) mode. fuel system operates in an open loop only, computer doesn't trust any sensors and uses preset fuel maps.

possible that the rear (meaning post-cat, under car) one might be going bad slowly as well, so consider replacing all of them over time. total around $250 if you DIY, new original Denso OEM sensors (just no Toyota logos on them) from ebay seller or amazon store.

check your part numbers here:
http://www.densoaftermarket.com/catalog/

then look for them on ebay and amazon.

[casey38boost]

cleared the codes, and p0125 and p1135 came back.

Guess i will start with the rear bank air / fuel calif. spec and go from there.

[fenixus]

yeah, AFR heaters are known to cause trouble. those OEM AFR sensors are said to last on average 150k miles or so. get a new one, probably original Denso OE will be your best bet both quality and price wise.

P0125 is something new. have you had it before? this is a serious code.
this is Insufficient Coolant Temperature for Closed Loop Fuel Control. this one causes all sorts of things to happen to an engine as this one alone throws ECU into a limp mode (same as P1135 does on its own).

might be caused by a stuck open thermostat, but also may be caused by a bad Engine Coolant Temperature for EFI sensor. try unplugging it on cold car once and read resistance off its terminals, do same when car is fully warmed up shortly after shutting down, remove an electrical plug from top of it and read resistance between its 2 terminals.

there is a chart you can compare those resistance to temperature readings with a graph and see if it fits specs or not.