Hello Toyota Nation:
I am attempting to fix a malfunction on my 2001 Toyota Highlander, V6 (1MZ-FE) engine with about 70K miles.
I have an Innova 3130 Diagnostic/Scan tool. It is showing a MIL code of P1155.
Elsewhere on the web (http://www.obd-codes.com/trouble_codes/toyota/
), I see that P1155 is listed as Bank1Sensor2. But the OBD-II scanner simply says "A/F sensor heater circuit malfunction'.
The scan tool is not able to perform O2 sensor tests on 2 of the 3 sensors. The one it does test is the O2SB1S2.
Also, I captured "Live Data" readings off the OBD-II and see Bank1Sensor1 O2S voltage of 3.96 Volts, and Bank2Sensor1 O2S voltage of 3.99 Volts. Whereas the Bank1Sensor2 voltage reads 0.8 Volts.
Haynes repair manual for Highlander indicates that the V6 2001 has 3 O2 sensors, of which 1 is downstream.
I would like to add that about a month ago, I replaced the BATTERY on the Highlander myself (auto zone). The battery was easy to replace and I did not have to juggle with any other cables etc. I hope I did not juggle something then.
Q1) Does all of the above information point to the (one and only) downstream sensor (B1S2) just ahead of the first muffler?
Q2) If so, is this really on O2 sensor or A/F (Air/Fuel Ratio) sensor?
Q3) If I have to replace it, do I have to remove the back seat and carpet to access it (as mentioned in Haynes guide), or can i disconnect cable from negative battery terminal and then access the sensor from under the car (which it seems is under the driver's seat as opposed to the rear seat).
Q4) On The Other Hand, is the B1S2 voltage of 0.8 valid? I.E. Is the voltage of a sensor proportional to the oxygen level, meaning does the low voltage indicate of B1S2 indicate a valid reading? Implying the catalytic converter is doing its job?
If needed, I can post more LiveData and/or FreezeFrame scanned information.