I had two fault codes set--P0134 and P0150. Sensor 2,1 had been malfunctioning and 1,1 had no signs of life. I replaced both today. Now. 2,1 appear to be working normally, but 1,1 still no activity. The OBDII diagnostic tool says the Sensor 2,1 voltage is .49 but the 1,1 is zero. So it appears to be that 1,1 is not getting any power. I have no idea where the problem mignt be--solenoid? fuse? the connector seemed ok.

Since the sensors began to fail, the vehicle has been running roughly
and now has a random misfire, which i assume is the result of the fuel mixture being wrong because the sensor isn't working.

I currently have expired tags because I cannot pass the smog test so any advice would be appreciated.
.

 

I think your O2 connector is bad so you can easily splice in a new one if it is the passenger side The driver side is a little tough. I had to splice into the main wire bundle running over the top of the fire wall.

If it is not the connector and is somehow a lack of voltage, the easiest would be to tap into any of the pink/brown wires in the top bundle (there are about 10-all hot) and run a cheat wire to the sensor.

 

 

Unfortunately these O2 sensor connectors are not completely waterproof, or at least they lose their sealing ability over time. You can clean the contacts with a bit of tightly rolled-up emery cloth and then spray out with contact cleaner. Reassemble with silicone grease on the male and female ends and it might solve your problem. Don't run the truck with no power to the sensor(s) or you could kill your cat converter on that side.

 

Swap the sensors left and right see if the problem stays on the same side.

Monitor the voltages on cold start, the ECU programs full rich on cold start so it should go close to 1v. If it does, then goes to flatline, you have an actual mixture issue on that side.

Sensors have 4 wires - two are for the heater, 12v+ and ground. The other two go to the ECU, the sensors generate + voltage 0 to 1 v.

Three possible causes for voltage issues assuming it is not an actual mixture issue:

1. Bad sensor - left - right swap will tell you if that is the problem.
2. Bad wiring between ECU and sensor. I have seen the pins push out of the connectors, or breaks in the wires. You can ohm them out from ECU to connector.
3. Bad ECU - I had the drivers for my oxygen sensors go out on one of my ECU's. Check the other two first, if you don't find the problem then you need an ECU swap. I recommend buying the complete ECU/BCU/Inst cluster off of ebay to swap in and test, if it does not solve your problem you can just resell it on ebay.

Good luck.

 

 

a lot of people have reported problems with bosch sensors being dead out of the box. walker brand sensors seem to have higher reliability.

 

You can disconnect the sensors and run without them, it might be a little rich but not as rich as a dead sensor which reads zero volts. It defaults to TPS and rpm maps in that condition.

I would not read anything in to the downstream sensors showing the voltage, they act different due to the cats, almost never cycle/fluctuate. If the front ones are bottomed out, the rear ones reading anything are meaningless.

You need a spare rover with good oxygen sensors you can swap in :-P Kidding. You can take your two old oxygen sensors, cut the connectors off, and wire them up back to back. Then take one of your rear sensors and put it in the front and connect it with the spliced connectors. The rears connectors are the mates to the fronts connectors.

 

I have been swapping the old and new sensors around in different pairing on both sides and get voltage readings on both sides. Around 1.0 on start then down to around .5. Certain sensors, however have caused the voltage to fluctuate between 1..0 and 3.0 incessantly while the.other side is stable when the engine is running. This has occured on both sides but with different sensors. The last time, 1,1 fluctuated like crazy while 2,1 started off at a stable .5 then slowly the voltage went down to zero.

The take away is this: there appears to be normal voltage on both sides because both sides have worked normally with some of the sensors, while some of the sensors don't respond to it on certain sides. I have no codes current or pending at the moment. Am I wrong to conclude that my filthy old sensors and probably one of the new cheap ones are bad and that the next step is to buy 2 new Walker sensors and see if they both function?
.Thanks to all again.

 

The 1,1 sensor has its own power wire.
Mine had a problem as well that I worked on for months.
Until I found the connector in the grey plug near the coolant reservoir was corroded.
I believe the wire is pink with a brown tracer, or vice versa?