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It was easy if you are running catless exhaust, just remove your rear 02 sensor from your exhaust and unplug it just tape over the other plug still on the car, and put the wideband sensor in its place, run the harness through the firewall via a grommet. Then run the harness up to the gauge and now you want to pull your clock out and unplug the harness and wire the red(ignition power) and black(ground) wires from the AEM harness, you will want to wire the red(ignition power) wire with the Green with Yellow(Ignition Power) striped wire on the clocks harness, and the black wire(ground) wires into the black(ground) wire on the clocks harness, then run the harness to the gauge and plug your clock back in and now enjoy your new AFR gauge.

Those of you with catalytic convertors will need a bung welded onto your downpipe, before the cat so it does not mess with the AFR's, AEM recommends you keep it 36" from the turbo so dont mount it right next to the turbo unless you want to replace sensors all the time. It doesnt have to be 36" away but just make sure you are at least 12" away from the turbo and make sure you mount the sensor either straight up or on a slight angle so that condensation can run out of the sensor.

don't you get the check engine light on for your o2 sensor being unplugged?

actually the XPT map turns off all the sensors for the rear 02 sensor anyway, I went through ecuflash and checked because you can actually turn your CEL's on and off. As long as you are catless downpipe and have gone in and turned the necessary CEL codes off which are like the rear 02 sensor voltage low, rear 02 sensor voltage high, and some others that would cause the CEL to come on with no rear 02 sensor.