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Unread 11-06-2013, 12:53 PM   #16
roadcruzer
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02 sensor

Quote:
Originally Posted by JS97ZJ View Post
I haven't replaced mine as of yet, and it tore off in the spring. That bogging down and poor acceleration is due to the upstream sensor going bad.
A bad upstream will also cause back firing and take out your cat very, very quickly.

It also might be that the colors are weathered. The diagram I posted is from the 98 manual and my 97 (hard copy) manual concurs with it.
So being your is not hooked up, did you notice any differences without it?

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Unread 11-06-2013, 01:00 PM   #17
V65Ozzie
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This brings back memories of my ASD system blowing fuses everytime I put it in gear..........yup, rear 02 harness rubbing on driveshaft.
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Unread 11-06-2013, 01:25 PM   #18
JS97ZJ
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Quote:
Originally Posted by roadcruzer View Post
So being your is not hooked up, did you notice any differences without it?
When the engine back fires, it blows the catalyst into the muffler.
Fyi, The bad cat is worth $, if the honeycomb is intact. The catalyst is made of platinum.
If the cat is clogged you'll get performance problems as well as codes. When it blows out the honeycomb, you'll also get a code ,indicating the cat is ng but you won't see much of a performance problem. The upstream sensor is still doing it's thing.
Guess how I figured that out?

Just make sure that the downstream wires don't make contact with anything under the Jeep. Fuse #7 in the PDC will blow and leave you under the Jeep when you lest expect it. If you keep replacing the fuse without fixing it you'll blow the PCM.
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Unread 11-06-2013, 08:28 PM   #19
roadcruzer
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02 sensor

[QUOTE=JS97ZJ;17488969]When the engine back fires, it blows the catalyst into the muffler.
Fyi, The bad cat is worth $, if the honeycomb is intact. The catalyst is made of platinum.
If the cat is clogged you'll get performance problems as well as codes. When it blows out the honeycomb, you'll also get a code ,indicating the cat is ng but you won't see much of a performance problem. The upstream sensor is still doing it's thing.
Guess how I figured that out?

Just make sure that the downstream wires don't make contact with anything under the Jeep. Fuse #7 in the PDC will blow and leave you under the Jeep when you lest expect it. If you keep replacing the fuse without fixing it you'll blow the PCM.[/QUOT

Thanks for the advise. I think I will keep it unhooked and see how she runs, someone previously gutted the CAT so even with the new exhaust I just put on tonight it is louder than normal but not too bad.
So I also think the front 02 sensor is bad (loose and it's not that it is not screwed in tight.) I think it is broke. Tonight it was idling in the garage and all of a sudden it just died. seemed flooded. waited a few minutes and it started right up and ran good. Do you think that is the front 02 sensor is causing this?
I just bought this Jeep last weekend for my kid. Have only drove it about 160 miles from where I bought it from. Ran like crap. When I got it home I poured a half bottle of seafoam down carb turned it off and let it set 15-20 min. Started it up and after the smoke cleared about 30 minutes later, I could see it again, she now runs like a champ. I do this on all my vehicles about once a year. I have a few more things to fix on it.
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Unread 11-07-2013, 05:08 AM   #20
ZeeJay1997
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Quote:
Originally Posted by roadcruzer View Post
Tonight it was idling in the garage and all of a sudden it just died. seemed flooded. waited a few minutes and it started right up and ran good. Do you think that is the front 02 sensor is causing this?
if the sensor is not connected, it cant be causing a problem. the stalling at idle could be caused by a number of things, but not a disconnected o2 sensor.

since you just got it, best thing to do would be start from scratch and run through the link in my sig. it's all maintenance that every ZJ should have.
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Unread 11-09-2013, 05:50 AM   #21
roadcruzer
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02 sensor-and my engine codes..

Quote:
Originally Posted by ZeeJay1997 View Post
if the sensor is not connected, it cant be causing a problem. the stalling at idle could be caused by a number of things, but not a disconnected o2 sensor.

since you just got it, best thing to do would be start from scratch and run through the link in my sig. it's all maintenance that every ZJ should have.
Seems after I ran some Sea Foam in gas tank and 1/2 bottle down carb it now stalls more than ever but runs a lot better that it did before the seafoam with the exception of the stalling now. Drove it about 10 miles and stalled around 6-7 time but would start back up. Sometimes easy and sometimes seemed hard to crank for a while almost acting like it was flooded. Last night idling it was idleing great then when it quit it sounded like a vapor lock. I ran the codes using the key method and below is what I got. Any ideas on where to start?( I do plan on going through a the steps) I just bought a new NGK front sensor I am going to install today. From the codes below is there anything that sticks out to you I should look at right away that I should do? May decide to use the wiring diagram you gave me for the rear sensor and hope it is correct.(afraid of blowing my PCM) Where do you suggest I start????

12 Direct battery input to PCM was disconnected within the last 50 Key-on cycles.
14 MAP sensor input above or below acceptable voltage. 5 volt output to MAP sensor open.
43 Misfire detected in one or more cylinders 1 thru 6. (4 and 6 cyls.)
21 (4 times) Upstream oxygen sensor response slower than minimum required switching frequency. Upstream oxygen sensor heating element circuit malfunction. Downstream oxygen sensor heating element circuit malfunction. Downstream oxygen sensor input voltage maintained above the normal operating range. Oxygen sensor voltage too low, tested after cold start. (Upstream or Downstream) Left oxygen sensor input voltage maintained above the normal operating temperature.
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Unread 11-09-2013, 07:23 AM   #22
JS97ZJ
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You can try disconnecting the battery to reset the computer so it can learn all over again.
It's not recommended running the engine with the o2 disco'd. The computer will keep searching for a happy medium and not find it and keep throwing codes.
ZeeJay's 12 things was devised due to the constant threads relating to stalling and performance problems. Go through his list again and recheck all systems.
You might have more than one problem going on there.
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Unread 11-09-2013, 07:36 AM   #23
ZeeJay1997
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if you can confirm the colors are as stated on the diagram, the diagram is correct. sometimes the stripes change colors due to the harsh environment, you may have to dig back into the harness to verify.

at this point, i would not try to repair the rear sensor wiring. just be sure it is isolated it from the circuit. this means be double sure no bare wires touching anything.

then leave the front sensor disconnected. there are several scanner codes that cause MIL 21 that could further isolate the problem, but for now we are eliminating the known trouble spots that could be causing the 21 and/or the miss.

try this: remove ASD relay (just to keep it from cranking). use two safety pins to make test points at the MAP sensor connector. on the two outside wires, slide a pin as far as you can into the hole where each of the outside wires enters the connector.

then use a meter on DC on a scale above 10 volts to measure the key on engine off voltage. it should be around 5 volts. then measure the same voltage while cranking and lets us know what you find.

i hope you have a meter...

as JS said, it is not recommended to run the engine with the front o2 disconnected for anything but troubleshooting.
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Unread 11-09-2013, 07:42 AM   #24
ZeeJay1997
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Quote:
Originally Posted by roadcruzer View Post
Where do you suggest I start????
do the test i mentioned below if you have a meter. then disconnect the battery to clear codes. then drive it with the rear wires isolated and the front sensor disconnected and see how it does. then come back and post any codes you have.

start with the the PCM, then the grounds, then the PDC, wiring and connectors.
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Unread 11-10-2013, 07:13 PM   #25
roadcruzer
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trying to get to it! more problems..

First I went to replace the front 02 sensor and after messing around getting the old one out with some heat, i went to put the new one on and it cross threaded. Had to tap the hole and use a thread chaser to fix my $50 new cross threaded sensor. After messing with just this a good part of the day(locating a tap and thread chaser) I noticed the main rear brake line that goes from the ABS box to the rear leaking at the rear hose. After making a couple more trips to the auto parts store, I finally got that all replaced.
Thanks for the info. Hopefully I will get to it tomorrow. FYI.. i did disconnect battery after installing the new sensors and reran the codes and got the same ones. Took it for a ride after that about 25 miles and stalled once. After replacing the brake line took it for a short ride to test brakes and it stalled 5 -6 times within a block... gas tank is now down to below a 1/4 tank. going to also install a new gas filter tomorrow. Do not understand. drove it 160 miles home where I bought it with no stalling. Now, randomly it may run for 25 miles or hardly go one block. I am thinking for some reason ever since I added seafoam in the tank, this problem started. I also just noticed after replacing the sensor now I hear a noise coming from the distributer but this also randomly comes and goes.(probably not related) you can actually feel it when you grab it. The noise also goes up and down with the RPM's but goes away at some point I can't explain this one either.... took cap off and all looked good. New cap and rotor in it also I will start more stuff tomorrow. I want to thank you for your support. I am ready to pull my hair out!!
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Unread 11-11-2013, 05:56 PM   #26
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Quote:
Originally Posted by ZeeJay1997 View Post
if you can confirm the colors are as stated on the diagram, the diagram is correct. sometimes the stripes change colors due to the harsh environment, you may have to dig back into the harness to verify.

at this point, i would not try to repair the rear sensor wiring. just be sure it is isolated it from the circuit. this means be double sure no bare wires touching anything.

then leave the front sensor disconnected. there are several scanner codes that cause MIL 21 that could further isolate the problem, but for now we are eliminating the known trouble spots that could be causing the 21 and/or the miss.

try this: remove ASD relay (just to keep it from cranking). use two safety pins to make test points at the MAP sensor connector. on the two outside wires, slide a pin as far as you can into the hole where each of the outside wires enters the connector.

then use a meter on DC on a scale above 10 volts to measure the key on engine off voltage. it should be around 5 volts. then measure the same voltage while cranking and lets us know what you find.

i hope you have a meter...

as JS said, it is not recommended to run the engine with the front o2 disconnected for anything but troubleshooting.
Zeejay, I just preformed the test as you instructed and with 02 disconnected, ASD unplugged, key on voltage was .04 volts. With engine cranking I had around 5.2 volts. Did a code read and now only get code 12 and 55. Also put new + connector on battery, cleaned up both +,- post, cleaned the post on the fuse block so far. What do you think? I have not started it since I did these test. Should I hookup 02, start and read codes again now?

12 Direct battery input to PCM was disconnected within the last 50 Key-on cycles.
55 Completion of fault code display on Check Engine lamp.
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Unread 11-11-2013, 07:47 PM   #27
ZeeJay1997
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sorry, i'm lost in the post here. so when you drove it and it was stalling, was the front o2 connected?

it will not code for the o2s right away after a pcm reset.

have you driven it with the front o2 disconnected?

what kind of o2 sensor did you install?

i'm not sure what's going on with the map voltage and the code you had. the PCM is looking suspect but we need to be sure the o2 sensors/wires are not causing a problem.

you've got to be sure none of the wiring is mangled/damaged/touching things.
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Unread 11-11-2013, 08:28 PM   #28
roadcruzer
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Quote:
Originally Posted by ZeeJay1997 View Post
sorry, i'm lost in the post here. so when you drove it and it was stalling, was the front o2 connected?

it will not code for the o2s right away after a pcm reset.

have you driven it with the front o2 disconnected?

what kind of o2 sensor did you install?

i'm not sure what's going on with the map voltage and the code you had. the PCM is looking suspect but we need to be sure the o2 sensors/wires are not causing a problem.

you've got to be sure none of the wiring is mangled/damaged/touching things.
I have not drove it yet since doing these test
I installed an NGK sensor.
All wires are secure and not touching inculding rear unhooked 02 sensor.
I Installed a new fuel filter tonight after doing your test. Started up and never missed a beat. Did not drive though ( Frikin snowing out) Ok, so it ran for 1/2 or so GREAT so after messing woth some stuff, heater control ect ( was not working but fixed it) and happen to press the AC button and it died instantly and now I have a no start condition. Did another code check after resetting a and got ;

12 Direct battery input to PCM was disconnected within the last 50 Key-on cycles.
43 Peak primary circuit current not achieved with maximum dwell time.
(only 1-43 flash) there is another saying 43 below but not sure if you need 2 flashes for 2 number 43's.
43 Misfire detected in one or more cylinders 1 thru 6. (4 and 6 cyls.)
I suppose it may have backfired when it quit , a little.

Is there a fuse to reset or replace? If so which one?
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Unread 11-11-2013, 08:40 PM   #29
roadcruzer
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Quote:
Originally Posted by ZeeJay1997 View Post
sorry, i'm lost in the post here. so when you drove it and it was stalling, was the front o2 connected?

it will not code for the o2s right away after a pcm reset.

have you driven it with the front o2 disconnected?

what kind of o2 sensor did you install?

i'm not sure what's going on with the map voltage and the code you had. the PCM is looking suspect but we need to be sure the o2 sensors/wires are not causing a problem.

you've got to be sure none of the wiring is mangled/damaged/touching things.
I have not drove it yet since doing these test
I installed an NGK sensor.
I also installed new + clamp, cleaned - wires and clamp, ground to fuse box, and ground on motor tonight.
All wires are secure and not touching including rear unhooked 02 sensor.
I Installed a new fuel filter tonight after doing your test. Started up and never missed a beat. Did not drive though ( Frikin snowing out) Ok, so it ran for 1/2 or so GREAT so after messing with some stuff, heater control ect ( was not working but fixed it) and happen to press the AC button and it died instantly and now I have a no start condition. Did another code check after resetting a and got ;

12 Direct battery input to PCM was disconnected within the last 50 Key-on cycles.
43 Peak primary circuit current not achieved with maximum dwell time.
(only 1-43 flash) there is another saying 43 below but not sure if you need 2 flashes for 2 number 43's.
43 Misfire detected in one or more cylinders 1 thru 6. (4 and 6 cyls.)
I suppose it may have backfired when it quit , a little.

Is there a fuse to reset or replace? If so which one? I have to believe this Jeep is trying this crap on purpose! Seems it is never the same thing.... WHat now do you suggest??? I try and start in the am and or after work tomorrow.

Thanks Again..
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Unread 11-11-2013, 08:44 PM   #30
ZeeJay1997
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those codes all relate to the noise in the distributor.

pull cap and see whats going on. may need a rotor or distributor.

looks like you may have had two or three different problems.
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