Dtc P0155 Help!!!

[LEADFOOT]

Hey everyone. Got me a new computer. Haven't been around much but now I have a computer since my brother moved out and took his with him months ago.

Ok on to my problem. Has anybody had the code P0155 show up? The code means this """P0155 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)"""
From what I have read its the O2 sensor on the pass side because bank 2 is the side of the motor with the #2 cylinder. Other codes say bank 2 sensor 3, what is sensor 3. And some say bank 1 sensor 3. I have 3 sensors, 1 on each down pipe and 1 after the cat. So what I am asking is if anybody knows which sensor I need to replace. I have 83,000 miles on my blazer, should I replace all 3 for the hell of it?

Also another question. I went to the 1/8 mile track the other night. Perfect racing weather, dry air temp about 65*. With these weather conditions I have ran 9.8ET before, and thats without the new aluminum drive shaft, 4.10 gears and ES poly mounts. Now with this bad sensor I couldn't even get to 10.1ET, was running 10.2 something all night, and thats with the recently added stuff I mentioned above. I didn't know a bad O2 sensor could cause this big of a difference.

My dad said it may not be the O2 sensor could be something else causing the ecm to think its the O2 sensor. I pulled the MAP sensor off the top of the manifold and it was wet with gas, not dripping or anything like that just wet and smelled like it bad. I thought the inside of the intake plenum was supposed to be dry because its a dry intake system. ANY HELP IS GREATLY APPRECIATED.

Check this out....I lined up next to a mustang cobra. I had a little less than half a car lengths lead off the line because of the mustangs manual trans., I stayed with him to about half track, and after that he started pulling away fast. Thats not normal for my truck. Normaly I do get beat of course, but not as bad as I did this time. And there was nothing special about this cobra, all stock.

[Sparky2263]

CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The control module supplies the HO2S with signal high and low circuits. Voltage and ground are supplied to the HO2S heater and is commanded ON or OFF by the control module. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the HO2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs leaner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the HO2S signal voltage.

The HO2S contains a heater that is necessary in order to quickly warm the sensor to operating temperature. The heater also maintains the operating temperature during extended idle conditions. The HO2S needs to be at a high temperature in order to produce a voltage. When the HO2S reaches operating temperature, the control module monitors the HO2S bias, or reference, voltage. The control module the HO2S signal voltage for Closed Loop fuel control. During normal Closed Loop fuel control operation, the control module will add fuel, or enrich the mixture, when the HO2S detects a lean exhaust content. The control module will subtract fuel, or lean-out the mixture, when the HO2S detects a rich exhaust condition.

This diagnostic trouble code (DTC) determines if the HO2S heater circuit is functioning properly by monitoring the time required for the HO2S to reach the operating temperature. This DTC sets when the powertrain control module (PCM) fails to detect HO2S voltage transitions above and below the bias range within a specified amount of time.

(Courtesy General Motors)

Terminals A and B on the O2 4 wire connector are the sensor. C and D are the heater. Most likely, the heater circuit is bad. An ohmmeter ck. across terminals C and D will reveal the heater circuit condition.

[LEADFOOT]

Thanks Sparky. I also read some more O2sensor info here. It was the pass. side sensor. So with 83k miles I just bought all three. I'll let you know how it turns out.

[T Man]

ouch, 3 new heated o2 sensors.....take out a loan for those?

[mrmidnight]

must have a sponsorship with Bosch

[Texashorsepower]

I got 3 new AC Delco O2 sensors on e-bay about 6 months ago for $25 each - Not quite loan criteria =-))

[LEADFOOT]

I got 3 new AC Delco O2 sensors on e-bay about 6 months ago for $25 each - Not quite loan criteria =-))
Damn, I got ripped at advanced auto parts. Didn't think about ebay for those.