97 Explorer Oxygen Sensor Replacement---HOW TO??

[1998rollover]

When my 98 was doing a code for Bank 1 cat efficiency below spec, I just said *bleep* it and got four Bosch sensors from NAPA.

My original plan was to swap the pairs of sensors side to side and see if the code changed banks, then swap either the upstream or downstream ones to see if the code changed again. Depending on results, I'd then know which was the bad sensor.

After getting the console out, my plan quickly altered! It took a chunk of 2x4, a 4 pound sledgehammer and another person in the back seat pulling on the console to get it loose! The only way that thing could've been installed was by a robot with a powerful push. I bent the clips some to loosen them up enough for a mere human to be able to reinstall.

There's also the problem of the one left bank sensor (the only one with the connector not on top of the transmission) having a shorter wire, which makes it impossible to install in any of the other three locations.

So yeah, it's worth the savings in time and frustration, plus the truck running better, to just "shotgun" the thing with a full set of new sensors. Shop around, especially online, and you should be able to find a better price.

Also check your sparkplugs. My 98 still had its original set of Motorcraft plugs! The one I measure was burned out to 90 thousandths, the rest looked just as bad. I've no idea how the thing was able to run, didn't run *bad* but did run better with new plugs.

Curiously, neither the new plugs nor new O2 sensors seems to have helped the MPG any, it just runs smoother. I'd think the O2 sensors would have to help MPG because with the code it had the computer would be constantly tweaking the fuel mix up and down more than normal, trying to get the downstream O2 reading in correct range.

 

[Joe Dirt]

+6 on the Motorcraft sensors. The "universal" types like Bosch seem to have issues after a bit, whereas the application specific sensors like the Motorcrafts do better over the long haul.

 

[drichardson]

hey fellas. i just picked up some new sensors but it doesn't say which sensor is which. I have the part numbers but can't find any details as to which sensor they are (upstream/downstream...). heres the part numbers:

Bosch: 15716, 15717, 15719, 15718

any ideas where i can find out more about these sensors so i can know where to install them? thanks

 

[1998rollover]

On the Bosch ones I got, the part numbers were for different wire lengths. The originals have keyed connectors. The Bosch ones have connectors that fit any of the four connectors on the wiring harness.

No difference between the sensors themselves. Do one at a time to ensure you don't cross up any of the three on top of the transmission.

 

[drichardson]

if they are interchangeable then why do some of the sensors cost more than the others?

 

[drichardson]

hey guys. so i managed to change out the 2 downstream sensors but when i cleared the codes and drove it around all the same codes came back on. i figured that by changing out 2 of the sensors, then the 2 corresponding codes would disappear, but unfortunately that didn't happen. could one bad sensor somehow be causing all these codes to appear?? i can't figure out what else to do... also i tried taking the center console out to get to the upstream wire harnesses but still couldn't get to them and ended up breaking my cd player in the process. any other tips on how to reach the upstream harnesses??

 

[gmanpaint]

Like I mentioned earlier...The connectors are the hard part. Frustrating ain't it?

Going in from the sides to get at them will work. This means removing the wheel, & wheel well liner, to get a clear shot at them. You have to use caution here as well. You don't want to be breaking clips, and stripping bolt heads doing this. Just take your time is all.

If you still have the console out, try using a Dental Mirror to see them and help guide your hands to them.

Sorry about the CD player, that sucks.

 

[drichardson]

hey guys, so i finally changed out all 4 sensors. i cleared the codes and drove home but my goddam "check engine" light came back on. all of the same codes appeared (check the beginning of this thread to see which ones). it's obvious that the issue is not the sensors themselves, since i just replaced all 4 of them. have any of you had this problem where you replaced the sensors yet the codes still came back??? i don't know what could be causing this

 

[1998rollover]

Then it looks like you probably get to replace some cats, if it's code 42 or 43.

 

[Turdle]

hey guys, so i finally changed out all 4 sensors. i cleared the codes and drove home but my goddam "check engine" light came back on. all of the same codes appeared (check the beginning of this thread to see which ones). it's obvious that the issue is not the sensors themselves, since i just replaced all 4 of them. have any of you had this problem where you replaced the sensors yet the codes still came back??? i don't know what could be causing this

That is what I tried to tell you. Please re read my posts. I was trying to help save some money but it seemed you were just wanting to throw money at it so I sat back and waited.

LIke I said, 4 sensors failing would be rare. It is in the wiring----

 

[96ExplorerX]

the codes are: P0135, P0144, P0155.

The mechanic that diagnosed my truck stated " Need to replace 4 O2 sensor ($155 x4), New spark plug wire sets ($175), Need to repair wire burn behind engine & fuse burn ($145). The total for all of this would amount to $940, I don't have that much to spend on repair right now, I just spent $1200 repairing it 2 months ago... Just trying to get the check engine light off so I can sell it and wash my hands of this mess

Why didn't you fix the burned wires and fuse first?
That's likely the source of the check engine light.

 

[OutofDate1980]

http://www.explorerforum.com/forums/showthread.php?t=209770&highlight=center+console

Thanks for the link on console removal. Autozone gave me the code PO134 for signal failure for the bank 1, sensor 1. I replaced all four sensors (120K miles) as three of them are so hard to get to. Going thru the access panel under the console is the only way, I know of, to get to the electrical connectors for bank 1, sensors 1&2, and bank 2, sensor 2.

When removing the old sensors, I found cutting the wires so you can use a deep socket (22mm) and liberal amounts of PB blaster was the only way I could get them out of the exhaust fittings as they were stubborn to remove.

As my original O2s were Borsch so I used the same brand. All but one were 15716's (10.63in), bank 1, S1 used 15717 (15.43in)

 

[Lechuga]

I only have 2 x O2 sensors upstream from (before the) catalytic converters and none downstream (after). Both wire looms plug in to sockets between the engine and the firewall. I guess this is not normal. I can barely touch them let alone try to get a multimeter in there or disconnect them

 

[Turdle]

There should be a sensor right under the transmission, and one hidden in the right side frame area. You might need to remove the center console to access the right side connector. While this sounds hard it will actually save a lot of time.

Measuring for voltage there is indeed tough. in any case you need to get to those connectors anyway "if" the sensors are bad. Do you have the 12v sensor heater voltage coming out of the PCM?

 

[Lechuga]

There should be a sensor right under the transmission, and one hidden in the right side frame area. You might need to remove the center console to access the right side connector. While this sounds hard it will actually save a lot of time.

I don't think I've got a standard setup. First of all my 98 Ex has 2 catalytic converters (one below the transmission and the other on the other side of the heat shield). I have relatively easy access to both O2 sensors, but their wires go directly up into the engine bay between the engine and the firewall. There are some wire looms above the transmission, but they seem related to the transmission itself. It is pointless, as far as I can see, to remove the center console, cut the carpet and access from above.

Measuring for voltage there is indeed tough. in any case you need to get to those connectors anyway "if" the sensors are bad. Do you have the 12v sensor heater voltage coming out of the PCM?

How do I measure that? I mean where should I be looking?

 

[Lechuga]

I'll try to measure DC using sewing needles

 

[NWExplorer97]

97 Lean Codes?

After reading this post and also experiencing intermittent codes for bank 1 &/or 2 (sometimes 1 or 2 sometimes both) to lean, I've also noticed the following;

BTW: I have my own scanner so each day I would erase the code at lunch time and drive home later with no code until the next morning.

After spring and summer driving with no codes, when winter temps got down to freezing the code(s) would set every morning on the way to work after about 4 miles of driving. I always let the engine warm up on start to about the same point or about 5 minutes. This happened several days in a row for a couple weeks. For the past 3 weeks outside temps have been above freeziing and no codes.

If the check engine light did not come on I wouldn't suspect any problem, runs great. Can anyone provide insight as to how outside freezing temps could possibly have an effect?

 

[NWExplorer97]

After reading this post and also experiencing intermittent codes for bank 1 &/or 2 (sometimes 1 or 2 sometimes both) to lean, I've also noticed the following;

BTW: I have my own scanner so each day I would erase the code at lunch time and drive home later with no code until the next morning.

After spring and summer driving with no codes, when winter temps got down to freezing the code(s) would set every morning on the way to work after about 4 miles of driving. I always let the engine warm up on start to about the same point or about 5 minutes. This happened several days in a row for a couple weeks. For the past 3 weeks outside temps have been above freeziing and no codes.

If the check engine light did not come on I wouldn't suspect any problem, runs great. Can anyone provide insight as to how outside freezing temps could possibly have an effect?

 

[sandivamp]

there is an access panel under the center console which you can remove for easier access to the plugs.

Oh sweet I was wondering if there was an easier way to get to them! Does this apply to a 96' as well?

Can you answer a couple questions Turdle?

I have a 96' explorer throwing the oxygen sensor codes though the guy at o'reilly's did it too fast so I need a new read to write down if it's bank 1 or 2 or bank 1 & 2

I want to replace them myself....I know I need the drive tool so would TEKTON 4929 3/8-Inch Drive by 7/8-Inch Oxygen Sensor Socket fit?...and also should I get the threader as well?

 

[Beargap]

My '97 with 4.0 pushrod was throwing codes of bank 2 lean and some research indicated that was generated by an O2 sensor reporting too much O2. Over time noted this was worse on very cold days and later on the truck started running more poorly. Turned out to be a couple bad spark plugs, which allowed unburned mixtures with the resulting higher O2 to be released. Replaced plugs and it runs fine with no codes now.

I did have a bad O2 sensor code about a year ago, Found the wires had been partially pulled from the sensor and the plug. Possibly could have spliced them, but it was easier to replace that sensor working from above through the transmission tunnel (manual trans) to get to the connector. I agree that sensors themselves seem to last a very long time (my truck has 300K miles), and if you're going to shotgun a repair, start with the cheapest/easiest things to do.