oxygen sensor code 1155

[stagescott]

heated oxygen sensor circuit, bank 2 circuit 1 has been activated...how to I repair this problem.Just change the sensor? Is this the sensor closest to the rear of the engine? Please help this DIYer...

[MR2Jedi]

IF this is a Turbo model-It's the sensor on exhaust side of the turbo. remove the 2 nuts and unplug it. The connector plug is near the IC fan. be carefull not to damage the O2 sensor gasket. They can be kinda brittle.

[ST185]

What year is your car? MRS?
P1155 = heat circuit malfunction of bank 1 sensor 2.
You have a 4 cyl, there is no bank 2.
Sensor 2 is located downstream of sensor 1.
This would be the after-catalytic converter sensor.

[tHa kNiGHt FaLL]

Originally Posted by ST185

What year is your car? MRS?
P1155 = heat circuit malfunction of bank 1 sensor 2.
You have a 4 cyl, there is no bank 2.
Sensor 2 is located downstream of sensor 1.
This would be the after-catalytic converter sensor.

yea............ but they like to call the downstream sensor bank 2... it doesn't make sense really when banks refer to even and odd sides of the motor

[OEMonkey]

Originally Posted by stagescott

heated oxygen sensor circuit, bank 2 circuit 1 has been activated...how to I repair this problem.Just change the sensor? Is this the sensor closest to the rear of the engine? Please help this DIYer...

Correct, that's the most common failure(heater code) on these A/F sensors fr Toyota. Just replace the sensor. If you wanna diagnose it first, that's easily done as well. Just check for open circuit voltage on the heater circuit KOEO.

On the MK III MR2, there are 2 pre-cat HO2S (or A/F Sensors for ca. emission cert. cars.) There's 1 closer to the driverside( for cyl 4&3), and 1 closer to the pass. side( for cyl 2&1.) I forgot which one is B2, S1. Both are equally easy to replace. BTW, the post cat sensor is B1,S2.

[stagescott]

Thanks guys... I have a 2001 NON Turbo MR2...(All stock) So I guess I just replace the sensor and all will be fine...