Yes, Bank 2 Sensor 1 is the passenger side front sensor. The sensor's electrical connection is secured with a push pin to a bracket. So you need to pop the connector out of the bracket, however you accomplish that (I used my long-reach spark plug wire pliers), pull the red locking tab, push up on the vehicle side lock and pull the sensor side connector out. Now you get to figure how to get the breaker bar on the socket to get enough swing to break the sensor loose. The van had been off long enough that the exhaust was cool, so I grabbed the propane torch and heated up the bung, then popped it loose with the offset oxygen sensor socket and my 24" breaker bar.

This is Bank 1, Sensor 1 (driver's side pre-cat), just to show you the oxygen sensor socket.

If you only have a deep socket, you can cut the wire and remove with the socket, then install with a wrench. But only if you're sure you can get it loose. The idiot that installed that oxygen sensor on my '99 before I bought it put it in so tight (and apparently without the copper goo), nothing got it loose. Absolutely nothing.

I installed the new sensor with a liberal amount of copper goo, then fought to get the electrical connection together and tight, get the locking tab reinstalled and push the connector onto the bracket. It's much easier to do that from above by removing the doghouse, but I didn't feel like pulling the doghouse two weekends in a row. So instead I cut up my hands on the heat shield and fought it for 15 minutes, but I got it done.

Having said that, make sure the wiring to that sensor is good and not pinched, cut, grounded....something.

 

I installed the new sensor with a liberal amount of copper goo, then fought to get the electrical connection together and tight, get the locking tab reinstalled and push the connector onto the bracket. It's much easier to do that from above by removing the doghouse, but I didn't feel like pulling the doghouse two weekends in a row. So instead I cut up my hands on the heat shield and fought it for 15 minutes, but I got it done.

Having said that, make sure the wiring to that sensor is good and not pinched, cut, grounded....something.

Never heard of copper goo, can I get that at the auto parts store? I am guessing just buy the O2 wrench to make my life easier? Purchased at the auto parts store as well? How can you check the wires...seems like the only way is to take the doghouse off and I'd rather avoid that if possible.

 

The copper goo comes in the box with the oxygen sensor. Yes, you can get the socket from your LAPS.

More than likely, the sensor is old and slow, which will throw the code. Replacing the sensor should clear it up. But do not buy a Bosch sensor unless you want to do this again soon. Very soon. NTK, Denso or AC Delco only.

 

Good to know, thanks. I will go out and buy the stuff today and replace it tomorrow.

 

The two passenger side o2 sensors in the front there stink. The one most forward, if I remember correctly, is the worst. I'd take the doghouse off because getting the sensor unclipped and reclipped will honestly take less time (including taking the doghouse on and off), than trying to make it work without removing the doghouse....at least for me.
Also, an o2 sensor socket is necessary for that one, I had to borrow a neighbor's and still fought it for like an hour.

 

Okay I bought NTK 21049 and installed. Vehicle is still showing same code. I've attached a screenshot of what the OBD was showing when I cranked it up. Also when I compared the old to the new, I noticed the new "shaft" was slightly smaller than the old (added photo of what I'm talking about) but this part says it is for my van, upstream right. Now what?

 

The two passenger side o2 sensors in the front there stink. The one most forward, if I remember correctly, is the worst. I'd take the doghouse off because getting the sensor unclipped and reclipped will honestly take less time (including taking the doghouse on and off), than trying to make it work without removing the doghouse....at least for me.
Also, an o2 sensor socket is necessary for that one, I had to borrow a neighbor's and still fought it for like an hour.

 

The two passenger side o2 sensors in the front there stink. The one most forward, if I remember correctly, is the worst. I'd take the doghouse off because getting the sensor unclipped and reclipped will honestly take less time (including taking the doghouse on and off), than trying to make it work without removing the doghouse....at least for me.
Also, an o2 sensor socket is necessary for that one, I had to borrow a neighbor's and still fought it for like an hour.

I was able to wrangle it from below (harness was the hardest part!) And getting the old one off with a socket was actually surprisingly easy.

 

Did you clear the code and it came back, or has it not cleared on its own?

You have to complete a drive cycle for that to clear on its own.

 

I did not clear it. So drive it for a hundred miles and see what happens?

 

I did not clear it. So drive it for a hundred miles and see what happens?

Not quite:

General Motors Driving Cycle

A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.

To perform an OBDII Driving cycle do the following:

Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.

Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.

Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.

Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.

Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.

Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.

Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.

Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

 

Oh okay that's detailed. Alright so once done with all steps should I expect check engine light to shut off?

 

Check engine light is still on but it's reading closed now. Good to go right?

 

It's in closed loop. Is the code stored, active or pending?

 

It's in closed loop. Is the code stored, active or pending?

Ahh, I have no idea. Just using Torque Lite and only know the basics of it. If you can lead me in the right direction I can check?

 

Pending codes should show grey or yellow. Active codes that should throw a check engine light are red.

However, apparently, not all ELM327 devices are created equal. Some won't show pending codes, only active ones.

EDIT: and I don't know about the free version because I have Torque Pro - I don't know if that makes a difference.

 

Okay new issues;
I drove probably 500 miles with no issues. Stopped at a gas station, filled up and turned the van on and check engine light came on. Here are the screenshots. 0155 is the one I just replaced.

Frustrated no doubt. Suggestions?

 

Unless you have a smog check coming up and you really want to get it to self clear, I would clear all the codes and watch it carefully.

Also there are a lot of mechanics I know of that suggest when one of the sensors fails, the others are likely starting to get "slow and lazy" so many of these mechanics will change all three at the same time. I don't recall how many "drive cycles" must be completed without an error to clear the P0155 but some of the codes require multiple "drive cycles" to clear. Others will clear on one completion of the self diagnostic. (like the P0457, fuel evap leak, most often a loose gas cap).

The other thing that happens if one sensor is lazy or slow, then when the PCM makes a fuel adjustment because one of the upstream sensors told it to, but the down stream sensor is slow in changing, The PCM may consider that the down stream sensor did not respond to the change and will flag it as bad where it may just be slow. Same issues with driver side to passenger side. If one sensor is working faster than the other, it can cause strange readings down stream.

The interesting thing is that P0155 is specifically a "pre-heat" resistor/element that is failing, not the actual o2 sensor, however when you replaced it, you may have changed the balance of how fast the PCM is expecting things to happen and the lazy sensors may now be showing their age.

This is why I suggested you clear the codes and see what happens. The PCM is somewhat adaptive where it tunes and adjusts to the drivers habits and the environment. If you clear all the codes, it will have to "relearn" everything rather than use old data from old sensors and try to figure out why one sensor is working faster than the rest.

 

Oh one other thing, A low battery or weak battery can cause some of these "preheat" issues. So can being in a very cold climate. Low voltage will cause a slow pre heat cycle and can cause the P0155. That's why in the drive cycle instructions shown by Leeann have the specific instructions to turn on certain other electrical things when you start the vehicle (trying to put high electrical load on system) Also why they suggest you do not turn key to ignition and allow to sit before starting because that will bypass the o2 preheat diagnostic, and thus not reset a p0155 error.

 

Also there are a lot of mechanics I know of that suggest when one of the sensors fails, the others are likely starting to get "slow and lazy" so many of these mechanics will change all three at the same time. I don't recall how many "drive cycles" must be completed without an error to clear the P0155 but some of the codes require multiple "drive cycles" to clear. Others will clear on one completion of the self diagnostic. (like the P0457, fuel evap leak, most often a loose gas cap).

I did the drive cycle and the code cleared on its own and then I drove at least 500 miles and these two codes were given. Could the sensor I just bought be crap? What is the other code about? And why is the fuel reading only 1 O2 sensor?

 

Oh duh, P0140 is another O2 sensor so that makes sense it is saying only 1 is working but then why is it saying it is a closed-loop?

 

140 is saying Bank 1, sensor 2 but I don't see this even indicated on an astro. I see Bank 1, Sensor 1 as upstream driver, Bank 2 sensor 1 as upstream passenger (what I already changed) and then the downstream as bank 2, sensor 2. What gives?

 

Leeann_93, thoughts?

 

I just called the auto parts store and I can return that O2 sensor I just put in, (NTK), they would need to order a new one. AC Delco is $119 for this and the rear. Do I clear the code and see what happens? Do I replace the upstream passenger and the rear? Do I fork over a ton more money and get the AC Delco? Trying to get out of town this weekend. Thanks everyone.

 

A code that points to a sensor isn't saying that sensor is bad and replace it.

It's saying that something's happening that the sensor cannot overcome. So it could be a dirty air filter, a dirty or bad MAF, a bad coolant temp sender, - anything that affects the fuel/air ratio.