[How-To] Wideband Install

The following is a guide for wiring up a wideband (referred to as 'WB' from now on) 02 sensor. It includes wiring up the signal wires so the WB output can be read by the ECU. This is optional, but handy if you want the data to be available alongside your AP datalogs.

Parts I used (not including gauge pod):

AEM 30-0300 X-Series Wideband UEGO AFR Sensor Controller Gauge

4-way Male Connector Plug Pigtail O2 Oxygen Sensor

Wire wrap

Add-A-Circuit

Electrical tape

Spade terminal connectors (if you need to extend any wires)

Tools:

Wire stripper/crimper

Wrench for sensor (can't remember size)

1. Install sensor. Location depends on where/what bung you'll be using. I have the Nameless DP with just two bungs. The rear OEM sensor is used just to verify the Cat is functioning and since my OEM sensor was actually failing, I chose to install the WB there. I just had to work with my tuner to make the necessary changes in the tune.

2. Wire up signal wires. Again, not necessary if you don't need to capture the data. Also, if you aren't deleting the rear 02, you'll have to take a different approach (you can splice in to the rear 02 harness or use the TGV input).

Connect the signal wires from the WB harness to the 02 connector. You'll be using the WHITE and BROWN wires from the WB harness. I chose to extend them a bit which is why you see red and black wires in the pictures. The pictures show where they need to be in the connector.

3. Route the two wiring harnesses through the firewall. I used the grommet behind the intercooler on the driver's side. I don't have a good picture but you can't miss it. I poked a hole in it and used a little grease to help get the wires through. This was honestly the hardest part of the whole process.

4. Connect power. The WB requires switched 12V power to function. I used the add-a-circuit and put it in the fusebox in the driver's side footwell area. You use the red and black wires, red going to the add-a-circuit and black being grounded someplace. No picture at the time. I can get one if it helps any.

5. Now simply plug everything in. The two sets of wire you ran through the firewall go to the back of the gauge. The WB sensor goes to the wiring harness (there is a connector on each end already) and the signal wires connect to the OEM harness using the connector you wired up. Use the wire wrap to tidy up the looks of things under the hood and add a little protection in the process. Zip tie excess wire out of the way.

6. Now turn the key to the "run" position and you should see the gauge turn on. It will say "HEAT" and a progress bar will move as the sensor warms up. If you get this far, go ahead and start the car.

7. Mount the gauge however you'd like.

8. Work with your tuner to get the signal from the WB to be displayed by the AP v3 (v2 will not show it).

Happy monitoring/logging!

Many thanks to cww516! Couldn't have done this without your help!

My original cry for help thread

Video:

It includes wiring up the signal wires so the WB output can be read by the ECU. This is optional, but handy if you want the data to be available alongside your AP datalogs.

Does this mean that if I would like to add a WB, but not the gauge pod, that I could wire in the WB in place of the rear O2 sensor and then my tuner would be able to use the data? (With my AP v3)

Does this mean that if I would like to add a WB, but not the gauge pod, that I could wire in the WB in place of the rear O2 sensor and then my tuner would be able to use the data? (With my AP v3)

Good question. The particular AEM wideband I used requires the gauge be used as well. It is involved in powering the sensor as well as converting the sensor signal to various logging outputs. So if you use the same one as I did, the gauge will be needed. However, now that my car is tuned, I could certainly unplug the gauge and tuck the wires away in case they are needed again. So that is an option for you if you simply need it for the initial tuning process. This whole setup is strictly for confirming the fueling is accurate during tuning, it serves no other purpose to the car afterwards.

AEM might make one without the display but I'm not sure.

AEM sells an inline wideband that is meant for people that don't actually need a gauge, like most people. It's the AEM 30-0310 X-Series Inline Wideband UEGO AFR Sensor Controller.

Good write-up!

Do you know the color of the wires from the rear o2 harness to splice into ?

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Do you know the color of the wires from the rear o2 harness to splice into ?

 

 

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You would be using the two bottom wires in the OEM rear 02 connector. I don't recall the colors, but if you pull back the wire loom a bit you will see them. I think they are blue and orange judging by what I wrote in the original thread.

Does the sensor in the AEM kit fit in the OEM bung location? No need to use the bung in the kit? This seems like a way better option than welding another bung location. Especially seeing as it's not needed post tuning, unless there is more tuning down the road, I suppose.

Just checking before I pull the trigger on the order.

How did you send your wideband signal to your AP?

I mention that above. You either wire the signal to the rear O2 or TGV input. Either way, the tune will have to be updated to interpret the signal and address any check engine lights.

I mention that above. You either wire the signal to the rear O2 or TGV input. Either way, the tune will have to be updated to interpret the signal and address any check engine lights.

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I'm about to install an in line wb. If I'm plugging directly into the rear O2 sensor, do I have to do the add a circuit part or can I simply just plug in the controller? I'm not using a gauge and just need to install it to allow the ap will read it so the tuner can work with it.

 

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If you want the info from the sensor to go through your AP, you need to wire it to the O2 or TGV. You tuner would then be able to see the info in the logs.

If you just hook up the sensor to the gauge in the car then you would need to record the info on the gauge in the car with a camera and send that with your logs to the tuner.

From what I have read in this thread and a few others, if I go with the inline WB controller, I can install it in place of the downstream OEM O2 sensor and wire it to use that sensor's CANBUS plug. I can then use the ECU to log the downstream O2 sensor signal, which will actually be the WB signal, using a Tactrix OpenPort for my tuner. The downstream O2 sensor position is not ideal for the WB, but it has worked for several others on the forum.

Once the tune is complete I could remove the WB (keeping it safe for the next tune) and reinstall the downstream OEM O2 sensor so I can (hopefully) pass emissions without issue, my j-pipe/downpipe is catted.

Is this correct or am I misunderstanding what I have read?

EDIT: After losing a bit of sleep over this, I realize that those people using the downstream O2 sensor location for the WB must be running without a cat. I also read that the upstream OEM O2 sensor actually is a wideband sensor...the more I learn about this the more confused I get

AEM sells an inline wideband that is meant for people that don't actually need a gauge, like most people. It's the AEM 30-0310 X-Series Inline Wideband UEGO AFR Sensor Controller.

 

Good write-up!

From what I have read in this thread and a few others, if I go with the inline WB controller, I can install it in place of the downstream OEM O2 sensor and wire it to use that sensor's CANBUS plug. I can then use the ECU to log the downstream O2 sensor signal, which will actually be the WB signal, using a Tactrix OpenPort for my tuner. The downstream O2 sensor position is not ideal for the WB, but it has worked for several others on the forum.

 

Once the tune is complete I could remove the WB (keeping it safe for the next tune) and reinstall the downstream OEM O2 sensor so I can (hopefully) pass emissions without issue, my j-pipe/downpipe is catted.

 

Is this correct or am I misunderstanding what I have read?

 

EDIT: After losing a bit of sleep over this, I realize that those people using the downstream O2 sensor location for the WB must be running without a cat. I also read that the upstream OEM O2 sensor actually is a wideband sensor...the more I learn about this the more confused I get

I'm using the rear O2 sensor with a catted J pipe. I have the wideband wired to the gauge in the car and sent video to the tuner for my tune. That would be the easiest way to get the wideband info for the tuner and return the car to stock when you're done with the tune.

Dave @ Cryo said the O2 sensors in our cars aren't sensitive enough to log the changes. I guess the newer 15+WRX's already have the upgraded O2 sensor in place, but we need to upgrade ours in the 5th gen LGT's.

OK, if you have successfully tuned with the WB in the downstream location than that seems convenient. I am going to wire it to use the ECU instead of using the gauge, I am using Btssm with the Tactrix OP for logging and do not want to run the wiring for the gauge into my cabin.

I'll then swap the OWM O2 sensor back in after the tune.

I'm using the rear O2 sensor with a catted J pipe. I have the wideband wired to the gauge in the car and sent video to the tuner for my tune. That would be the easiest way to get the wideband info for the tuner and return the car to stock when you're done with the tune.

Dave @ Cryo said the O2 sensors in our cars aren't sensitive enough to log the changes. I guess the newer 15+WRX's already have the upgraded O2 sensor in place, but we need to upgrade ours in the 5th gen LGT's.