been noticing a drastic change in fuel usage, i filled er up and got 140 km's out of a half tank, i heard my cat doin some rattling the last bit, still have power it seems, but i didnt think i'd lose that much gas cus of it, anyways my buddy scanned it today and it shot off code P0155, h02 bank 2 sensor 1, is this my problem there? showing no misfires at all or anything, and another question does anyone know what side that sensor is on? thanks ahead of time, great forum

2003 Blazer LS 4x4

 

That could be it. P0155 is indicating a problem with the O2 heater, passenger side sensor closest to the manifold. If the sensor doesn't get up to operating temp, the PCM will keep the fuel mixture richer than necessary. That may have caused a problem with the converter as well.

 

ok ok, so that being the sensors no good or is there something causing the sensor to do that i.ie something else is the problem too possibly..?

 

Great question! You can find out by following each step of the diagnostic flow chart: https://blazerforum.com/forum/diagno...plained-35155/ When you finish, clear all memories and perform the General Motors Driving Cycle You must complete each step exactly as written. The steps do not need to be performed in order, but each step must be completed. If the check engine light remains off after completing the drive cycle, there are no other problems with the OBDII system.

Generally, a converter failure is not usually the cause of a problem, but rather the result of another problem.

 

I had this same code recently, about 3 months ago, and I swapped the passenger side sensor with the sensor post converter. They are the same p/n. Might be worth a try before buying a new sensor. At the very least it should throw a different code if the o2 sensor heater circuit is truly defective. Buy ac delco sensors only.

Here is the cheapest I could find when I thought I was going to buy one. I have bought other parts from them and they are fast on delivery.

ACDelco 213 802 Oxygen Sensor | eBay

Auto parts stores will loan o2 sensor removal tools.

Captain Hook. Do you know if the post converter uses the heater circuit?

 

I used the Densos from rockauto as they are the OEM maker for GM. DO NOT buy a bosch O2 sensor, nothing but issues.

 

ok awesome dudes, thanks, i'll see what happens

 

CAB, 1996 and newer, all O2's have heaters.

AC Delco & Denso are the 2 fastest reacting oxygen sensors, with Denso being slightly faster. Denso sensors are cheaper than AC Delco BUT, they don't last quite as long. Delco's are good for ~100K miles and Denso's ~80K miles.