neonglh

iTrader: (42)

So I keep getting P0171 and P0134 codes. I tracked them down to the front o2 sensor not working correctly. We tried a second o2 sensor (used, laying around the shop), and the check engine light came back on after about 5 miles or so. After hooking it up to Evoscan, we were able to watch the logs, and the rear o2 is working how it should, it moved around 0.97xxxx and bounces around like it should. The front o2 reads almost constantly stay at 0.0, and then jump up to 0.020 randomly, and then go back down to 0.

So, my next step is to find out if chance has it both o2 sensors that I tried are bad, or if something on the car is bad. The wiring is all stock on the car, so no reason why it should be bad, but it's pretty odd luck to try 2 bad o2 sensors!

I want to check the sensor itself with a multimeter, and see if the readings are within spec. Does anyone have a FSM, or other manual that explains how to do this? That would be a great help.

Thank you much!

-mark

neonglh

iTrader: (42)

Anyone????

TommiM

iTrader: (19)

a meter averages readings so its not as accurate as using something like a snap on vantage that will graph. The O2 sensor should change from .450 to .900 iirc. Either way, you should see the values changing high/low/high/low. You should be able to see this using a scan tool as well. There are specs as well, you can do a resistance check between the terminals and see if they fall within spec, using the ohm meter function of your meter.

novem

iTrader: (2)

I had the p0171 code..took a look around and the BOV popped off my AEM intake. I reset the code and it never came back. You may want to take a look for exhaust leaks also.

N

novem

iTrader: (2)

OEM most likely causes are...

*maf failure ( should read 56hz or less)
*injector failure
*incorrect fuel pressure (vac hose disconnected at idle 85.3-91.2 in.Hg..connected 33 in.Hg)
*air drawn in from gaps in gaskets, seals, etc.
*heated 02 sensor failure
*intake air temp sensor
*baro sensor failure
*use of incorrect or contaminated fuel
*ECM failure

Heated 02 sensor specs

Output voltage 0.6-1.0V
Heated 02 sensor voltage resistance
4.5-8.0 ohms
11-18 ohms

Good luck!

N

barneyb

I remember checking what I thought was a bad O2 sensor on my now gone DSM. The trouble was I also had to have the sensor heater going. There were two pins for the sensor reading and two pins for the heater – 12 volts and ground. The heater I ran directly off of the battery. I was trying to stuff four wires in the plug with alligator clips and the next thing I knew, I had a welder.

Back at square one, I realized that I needed more secure connections that were insulated. So, I found four female pin connectors the right size and after crimping them to wire, I wrapped them with tape so that they were completely covered. Now, I could connect all four wires to the O2 plug without risking a black face.