2003 Toyota Avalon Check engine light code P0155

BWFCI

MEMBER
2003 TOYOTA AVALON
6 CYL
2WD
AUTOMATIC
54,000 MILES

Check engine light on for last few months. Needed inspection done, so I took to o'reilly and they said, Code P0155 is Bank 2 Sensor 1 Oxygen Sensor according to o'reilly auto parts.
So, I replaced myself, with Bosch 13540 bought at o'reilly for $169.99 (way overpaid now that I check online prices). Check engine light still on. So I stopped in an inspection place, they reset the code, and it immediately popped up again. Looked online, someone suggested to check the fuses (somewhere I read that).
So I pulled and inspected all the simple fuses that seemed to be connected to emmissions.
Then, when I started the car, the check engine light was off (1st time it came off in 4 months).
But, went back on after 30 seconds. So, I figure I cleared the code by removing power (by pulling the fuses), but cause is not fixed, so code came back on. Need some advice on how to proceed.
I also found it outrageous that Midas quoted me $300 to fix when it took me 20 minutes to replace the oxygen sensor. Of course, now I have spent $170 and still do not have it fixed. Any suggestions GREATLY appreciated!

3 Replies

SATURNTECH9

MECHANIC
30,870 POSTS

First question I have to ask before we get too far into this is which exhaust manifold did you replace the o2 sensor on?Sorry have to ask this I wasnt there to see when you changed it.

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Tuesday, December 10th, 2013 AT 3:23 PM

BWFCI

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2 POSTS

Changed oxygen sensor in front manifold near oil filter between radiator and engine.

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Tuesday, December 10th, 2013 AT 4:34 PM

SATURNTECH9

MECHANIC
30,870 POSTS

You replaced the correct one I posted a pic of the the power and ground to the heater on the o2 sensor. The code is for the heater circuit lets start by checking the heater on the new sensor just to make sure its good. Get a mult meter set it to 200 ohms scale unplug the o2 sensor then check across the terminals of the sensor connector like the pic shows. You should see around a couple of ohms resistance. If that's good with the key in run position engine off sensor unplug check the harness side of the sensor. You should have battery voltage on the B+ terminal and 2 ohms or less to ground on the other terminal it shows iin the pic.

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