1972nova

iTrader: (13)

Ok so I got the nova to start and working through a SD tune with the Tuner. we have issues with both bank 1 and 2 front o2 sensors

With the key on engine running the sensors are not responding they are at the default .450ish number and as soon as you back the key to the off position and the data logger stops logging it shows the o2's respond and they show values.


A little run down

Techrods 5.3 truck harness cable drive
0411 pcm
370" LSx 4788 turbo
brand new bosch 4 wire 02 sensors
no faults for 02 sensors at all


I have an email into techrods but have not heard back yet
Just looking for some help

1972nova

iTrader: (13)

harness wires are

A- TAN
B- Purple
C- Black
D- Pink

leading into a bosch 13193 o2 sensor 4 wire translates on the o2 wiring side

a-grey
b-black
c- white
d-white

1972nova

iTrader: (13)

from harness
A- tan 5v key on and key on running
B- Purple 5v key on and key on running
C- Black Ground
D- Pink 12v


I post above but its currently wired
Tan-Grey
Purple-Black
Black- White
Pink-white

Seems it has to be an o2 issue these are brand new but of the options wonder if I should of had 13444 or 13474

1972nova

iTrader: (13)

so pretty much my bet is going to be either faulty 02 sensors (both) which would only mean to me that the sensors are not correct for my app

or

faulty ecm

BLK02WS6

iTrader: (2)

I think most of the 4 wire sensors use the same wiring configuration - I'm betting the harness is wrong... highly unlikely 2 new sensors are bad...

Maybe see if you can find any info on the wiring of a Bosch sensor on their website...

1972nova

iTrader: (13)

should both tan/purple wires be seeing 5v. I thought the sensors operate 0-1v

1972nova

iTrader: (13)

I will check that here tonight what I found is with the o2 screwed into the bung but the harness unplugged from the ecm I am showing 5v on both low and high side of the o2 sensor.

When everything is plugged in (ecm and o2s) I turn the key on and the values go straight to 450mv and as soon as I turn the key back before the logger loses connection with the pcm the values show them working they go down to 20-40mv.

Went through the brand new techrods harness and verified with a pinout from alldata that everywire is where it is suppose to be and every wire that needs a ground is seeing that and every wire that needs power is there.

We tried a known good pcm as well aside from mine. I dont under stand how there is a 12v between the pink and harness ground and with the sensor unplugged there is 5v on both of the reference wires, is that normal? is there a chance that I need different o2 sensors. Just crazy that with all this work looking into stuff nothing stands out to me.
__________________

oange ss

iTrader: (50)

double check the pinouts on the ECM connectors. There is a diagram around here somewhere

1972nova

iTrader: (13)

**UPDATE**

PROBLEM SOLVED. In case someone else runs into this and cant figure it out like it took me forever to do.

Depending on your year of pcm and wiring harness GM used two different types of 02 sensors. Case grounded and Isolated ground, Comparing the 2 truck wiring diagrams and an fbody 411 pcm diagrams I checked the wiring and see what wire for the o2s went to what pins on the C1 blue ECM connector.

It matched the diagram for needing a sensor for case grounding

For my situation I was using a brand new bosch 13193 sensor which had a white connector. From what I reasearched the white connector was an o2 for isolated grounding sensor. My PCM was looking for a case ground to complete the circuit and I needed either an fbody sensor or a truck sensor with the black square 4 pin harness.

Went to Jegs down the street and picked up two bosch 13474 sensors for 28.99 each and fired it up and the logger immediately started reading voltage.

BLK02WS6

iTrader: (2)

Good to know - didn't know they made that type of sensor that would plug in to the square harness!

lakin454

This just helped me figure out why my 02 sensors weren't working. I've been puzzled for a while on this. Thanks for the post.

1972nova

iTrader: (13)

glad it helps, always hate searching threads and you find a similar problem but the OP does not post the solution. That problem chapped my *** for a little while until I figured it out.

lakin454

Did the bosch 13474 sensors (Black harness) fit into the existing white connectors you had on your wiring harness? I tried what you did and the 13474 sensors won't fit into my plugs (White 13193 sensor)

Sarg

iTrader: (6)

Any clue which year wants what? I have a 2001 pcm with a 2000 fbody OS flashed on it.

Tj McFaul

Thank you so much for this thread! I have been fighting this issue for months now and finally can get my tune done!

josefb134

I've got the same voltage readings and issues you seem to be describing on a 411 PCM. Problem is, my standalone wiring harness has the Long Black female plug from the Bosch 13474 o2 sensor. So that means I wont be able to use the o2 sensors suggested without trying to rewire them. I've looked and looked and cannot seem to find the same case grounded o2 sensor that has the male connector needed. I thought about using some sort of universal case grounded plug, but I don't really trust those butt connectors and I've heard you cannot solder new connectors on because the solder messes with the signal reading. I've searched for the crimp pins to swap the connector but haven't came up with anything either. Does anyone have the part number for a Case Grounded 4 wire o2 sensor that has the male plug on it? Thanks so much!

lakin454

This may not be correct, but what I did was carefully break off the little plastic tab inside the female plug (that restricts it from going all the way on) with a small flat blade. Then it's able to plug into the white male connector. Again that may be completely wrong but it is how I got mine working. Good luck

josefb134

I wish that was the only issue I was having and I appreciate your effort to help! Unfortunately, my wiring harness has the same female plug that the above mentioned O2 sensor has. So no matter what they wouldnt plug together without changing the connectors. I'm working on trying to find an o2 sensor with the male connector that is case grounded.

josefb134

*UPDATE* Got everything working as it should and I figured I would share all of the knowledge I’ve gathered to help anyone else out that is having this issue. First, here’s a little info on my particular build:

Vehicle: 1958 Chevy Biscayne 4-Door
PCM/ECU/ECM: 411 Blue-Red VIN: 3GNFK16ZX2G358292 from a 2002 Chevrolet Suburban 1500, 5.3 L, V8, GM_P01
Engine: 2002 5.3 LS Truck motor from above vehicle
O2 Sensors correct for this specific PCM: Bosch 13474 which is CASE GROUNDED (~$60 each at Oreilleys)
Wiring Harness: eBay Stand Alone Harness with o2 sensor wires colored Pink, Black, Purple, and White/Red (White with Red stripe).

My eBay Standalone Harness had the Long Black Female 4 Pin Square Connector GM uses and that the above Bosch 13474 uses. This required me to create an adapter harness for both Bank 1 and 2. Bank 1 is Driver side and Bank 2 is Passenger Side. I’ll explain a bit more about the wiring adapter harness in a minute. The other issue I ran into was that I was not using a Case Grounded o2 sensor, I was using a Denso 234-4651 which was an Isolated Ground o2 sensor, meaning it had its own ground and was not grounded through it’s body or the exhaust.

Note* Info I’ve learned about o2 sensors that might be helpful in your diagnosing. The Low Signal wire is technically a ground or is grounded via the body of the o2 sensor even though the harness puts out around 5v. I kept putting my black ground wire to the grey o2 sensor ground wire thinking the ground needed to match up but then I wasn’t grounding the heating element. The heating element needs a dedicated ground and 12v power. The low signal wire acts as a ground or something to the high signal wire for the o2 sensor. Next, o2 sensors will read 0.45v on HP Tuners until they get up to operating temp. o2 sensors produce their own voltage to tell the computer how much o2 is in the exhaust as if they are a mini generator and they have to heat up before they can start producing that voltage. That is why newer ones have their own heating element. One thing to note about the heating element that I have found, the element only heats the inside sensor so the body and even the tip will not instantly get hot when you turn the key on, they will eventually but not right away. When testing to see if my wiring was right, I had the o2 sensor grounded and the key on but was confused why the body wasn’t getting hot right away. Turns out it was the sensor inside getting hot and I could feel the heat start to come from the vent holes but the tip and body were still cold. Once the sensor started reading, you could feel the tip start to get hot. Once the sensor is installed, the car is running, and the o2 sensor is heated up all the way, the voltage should jump back and forth from 0.1v to 0.9v very rapidly, multiple times a second. Your car’s computer will adjust the fuel multiple times a second from lean to rich based on these values. An oxygen sensor will typically generate up to about 0.9 volts when the fuel mixture is rich and there is little unburned oxygen in the exhaust. When the mixture is lean, the sensor's output voltage will drop down to about 0.1 volts.

PCM Info: Your 411 PCM might have a Blue-Red or a Blue-Green harness attached to it. There are two blocks of wiring that attach to the PCM, one is Blue and the other is either Red or Green. There are some differences but for the o2 sensors, it shouldn’t matter. Pinout readings will show C1 = BLU and C2=GRN/RED. If you don’t know what side is Blue, Red, or Green, you can either unhook the wiring harness from the PCM or you can look on the side where each one plugs in and catch a glimpse of BLUE, RED, or GREEN between the connector and the PCM on the side of the PCM. If someone says Pin 29 Red/Green, that means it’s pin 29 on the Red or Green connector.

My BEST o2 Wiring Tip: There should be tiny ABCD letters on your o2 connectors on your wiring harness or your plug that goes into the wiring harness. Take a look at those letters and then throw them out the window lol They get extremely confusing on forums because everyone is looking at different diagrams on how to read them and they swap places depending on the color of plug and if it’s a male or female plug. Your best bet is to check your wire colors, check and verify voltage/continuity with key on, and match the o2 sensor wires with the corresponding harness wiring I’ve laid out below. I will explain how to depin and repin your connectors below or you can search it up on google.

Wire Color Confusion - Purple wire might look blue from chemicals or element exposure. I was very confused until I stripped back the harness wrap and found it turned Purple on the non-exposed part. Same thing with my Pink, it looked orange until I investigated further. Check your voltages/Grounds with the key on and off, figure out what is what, and write down the configuration to use when wiring up the o2 sensor.

Bosch 13474 - CASE GROUNDED – Wire Color Meanings

O2 White – Heater Low Control – Heater Ground - White wire polarity doesn’t matter
O2 White – Heater Power – 12v Power - White wire polarity doesn’t matter
O2 Grey – Ground – Low Signal Wire
O2 Black - Signal Wire – High Signal Wire



Key-On – Engine-Off Readings & Master Descriptions from o2 harness:

Black (Black with White Stripe or Light Green = Stock Color)
Multimeter Reading: Ground – Check for continuity to engine/frame
Description: Heater Low Control - PCM Controlled Ground
Match to o2 wire color: Either White wire on o2 sensor – polarity does not matter with o2 heating element.
PCM Pinout: Bank 1 is Pin 72 Green/Red, Bank 2 is Pin 74 Greed/Red.
*NOTE* Some standalone wiring harnesses do not pin these to the PCM and run them straight to a ground that the harness uses. As long as you have continuity from the wiring harness pins to the engine/frame grounds, you should be fine.



Pink (Pink = Stock Color)
Multimeter Reading: 12v
Description: Heater Power – Powers o2 sensor Heating element - Key Switched on Battery Power from Fuse Block
Match to o2 wire color: The other White wire on o2 sensor – polarity does not matter with o2 heating element.
PCM Pinout: Does not connect to PCM - Key Switched Battery Power from Fuse Block



White/Red (Tan = Stock Color)
Multimeter Reading: ~5v
Description: o2 Low Signal – Grounded Via Body of Sensor
Match to o2 wire color: Grey “ground” Wire
PCM Pinout: Bank 1 is Pin 29 Blue, Bank 2 is Pin 26 Blue



Purple (Purple = Stock Color)
Multimeter Reading: ~5v
Description: o2 High Signal – Sends signal from o2 sensor to PCM
Match to o2 wire color: Black signal wire on o2 Senso
PCM Pinout: Bank 1 is Pin 69 Blue, Bank 2 is Pin 66 Blue




How to Depin and Repin your Connectors

Female Long Connectors: First, use your fingers or a flathead screwdriver to unlatch the wire retainers on the bottom of the container. These keep your wires in place in case the latch gets damaged as well as helps seal the rubber gasket around each wire. Get yourself a straight and very small pick, needle, or other tool small and long enough to go down into the hole next to the pin. There is a little latch that you will need to move towards the pin that is sticking up. You’ll pull on the back of the wire gently but firmly as you push that latch to the side to release the pin from the connector. Once you remove it, you will likely need to push that little lever back out so it catches on the connector when inserted. Swap your wires around and re-insert them. Then once all are inserted, put the wire retainers back on the back of the connector.

Male Short Connectors: You are basically doing the same thing as above. Only this time, the latch is on the small hole to the side of the pin. The latch is not in the larger hole of each pin, that is where the pins insert from the long female connectors. These pins require a little smaller of a pick/needle to fit into that smaller hole. Don’t forget to bend the latch back out so it latches again and put the wire retainers back on when all the wires/pins are inserted.

josefb134

How to Create Adapter Wiring Harness

For this project, both the Bosch 13474 and my wiring harness had the same long female connector. This meant I had to make my own male to male 4 pin square adapter harness. To do this I bought 2 of these:

Michigan Motorsports LS1 02 Oxygen Sensor Header Extension Harness 24 inch 4 pin

I bought two because you have to have 4 male connectors total to make a Bank 1 and 2 adapter harness. I also bought waterproof/heat shrink butt connectors from Lowes but they are way cheaper on amazon:

22-16 AWG Waterproof Red Heat Shrink Butt Connector

The red 22-16 AWG butt connectors worked perfectly with the wire size in the extension harnesses above.

*NOTE* I know butt connectors suck and it’d be nice to solder these but o2 sensors are wack and they actually transfer oxygen within the wiring harness/wire shielding and that is supposedly how this o2 sensor gets its external/outside o2 reading to compare to the exhaust o2 readings. If you solder or use silicone you disrupt that flow of tiny o2 particles and it can lead to your o2 sensor failing or giving false readings. Butt connecting allows those o2 particles to pass through and work as normal.

It’s also a good idea to get some heat shrink tubing that will fit directly over the shrunk butt connectors. I believe 3/16 is what I used but I had an assortment so I couldn’t really tell you. This is more of an extra precaution and not 100% necessary.

Once you get all of those, it’s time to party.
1) When first cutting the wires in the extension harness so you have 2 male connectors to work with, you’ll have to slide the heat protective sleeve down to cut the wires or you’ll have to depin the long female side to slide everything off. Another alternative is to just cut the long female end off right at the connector. You’ll just have a ton of extra wire to play with or cut off.
2) Next, you’ll want to follow the directions in this Universal Denso o2 sensor pdf on how to cut the wires and connect them in such a way that you don’t have butt connectors overlapping. Basically you stagger the wires so the butt connectors don’t all bunch up in the center. This is just a cleaner solution and allows you to use the heat shielding that came with the extension harnesses. The PDF might be using a different length butt connector so just double check before cutting.
https://assets.sparkplugs.com/docume...structions.pdf
3) Before you install any of the butt connectors, put the heat shrink on the longer section of wire. Getting the heat shrink over the wire seals at the pins is a bitch and probably won’t be possible.
4) When wiring, you’ll have 4 wires: Red, White, Yellow, and Black. Butt connect red to red, white to white and so on. Otherwise you’re going to have a terrible time.
5) Once all the butt connectors are crimped and tug tested, you’ll want to check for continuity at both ends of each wire.
6) Then, you can heat shrink the butt connectors so they form a seal on the wire. If you are also using heat shrink tubing, be careful to keep the heat away from the heat shrink tubing and allow the butt connector to cool before trying to push the tubing over the connector. If it is still warm, the tubing will immediately shrink and you won’t be able to push it on any more.
7) Once all of the heat shrink and such is in place and shrunk, you will probably have to depin one of the smaller male connectors to slide the heat shielding back over your finished product. You’ll have to cut the heat shielding to size. Make sure you leave enough room to put the wire retainer back on without a fuss.
8) Then you can repin the connector and reattach the wire retainer. Make sure the wires are in the same orientation with the latch/tab pointing up on both ends of the plug. For example, mine had yellow on bottom left, Black on top left, red on top right, and white on bottom right on both ends/connectors. You want to make sure the colors are in the same ABCD configuration on both ends.
9) Lastly, You’ll want to test for continuity one last time for each wire and ensure everything is in the same configuration.
10) YOURE DONE! Now go plug in your new adapter harness to your standalone wiring harness and o2 sensor and enjoy!


Links that have helped me find all of this info and figure out my problems:

https://www.lt1swap.com/vortec_o2_sensors.htm

https://ls1tech.com/forums/pcm-diagn...s-411-pcm.html

https://ls1tech.com/forums/conversio...nfusion-2.html

https://www.astrosafari.com/threads/...al-wire.12471/



I tried to lay all of this out as easy as possible and I really hope this helps others in my situation. If this helped or if things need further clarification, please let me know and I’ll do my best to help!