Review on 🔥 Denso 234-9041 Air Fuel Ratio Sensor: Enhanced Engine Efficiency and Performance by Kevin Grizzle

I had this problem: On the dashboard: VSC + Check engine + 4WD light on. After installing the product I've ridden over 200 miles in the last few weeks and still have no problems. I don't expect anything either! Here's how I did the $400 job myself: --- I have an OBDII reader that helped me pinpoint the cause. This is an air fuel sensor aka upstream O2 sensor aka bank 1 sensor 1 of the RAV4. It determines the stoichiometric ratio of air and fuel in the combusted mixture (the ratio at which the fuel burns completely, 1:14.7 or something like that). It does not behave like the downstream O2 sensor. The CPU is constantly adjusting the voltage/current, so reading the voltage on the sensor doesn't tell you if the sensor is bad or not. You read it after the processor and that means the OBDII reader is high-end. Reading the resistance won't tell you much either! -- Order with some risk that the electrical plug will not fit. Make sure you can return. Upon receipt, check the correctness of the plug. --- Order an O2 sensor socket (has a slot on the side). Most of them have a 3/8" drive with a 7/8" socket. -- Let the engine idle for 30 seconds - no more. It will warm up a bit. Located on the exhaust manifold that comes directly from the engine. It's on your right when you face the car. There will be a cable going there. -- Wet the base of the existing sensor with Liquid Wrench Penetrating Oil (not for garage doors). lubricate!) Wait 1 hour for the liquid to loosen the rust.-- Disconnect the negative battery terminal and wait at least 30 seconds (sudden airbag deployment). Try removing the existing sensor with a 3/8" and 12" torque wrench. If the thread doesn't loosen to about 40 ft-lbs, soak it again and try again. Do not use force, otherwise the thread may tear ($$$). A light tap on the base will help loosen. -- If it won't come loose, take it to Meineke or where you can install it -- Remove the battery after loosening! This gives you direct access to the sensor. r hole on this side. Install a new sensor using the lube provided, just enough to get a thin coating on the threads. Tighten it by hand first. Make sure you tighten it to 32 ft-lbs. Make sure the cable is routed through the hose clamp so it doesn't touch anything that gets hot. Reinstall the battery. Reconnect all cables and start the engine.-- Check for exhaust gas leaks. You will see smoke-like water vapor coming from the base of the sensor. I installed the torque wrench incorrectly and it had 30 ft lbs on it. And it worked! In the event of a leak, stop the engine immediately. There is a risk of carbon monoxide poisoning. Tighten a little more. Be careful ,. It will be hot! As soon as I re-tightened to 32 ft-lbs the leak stopped. Disconnecting the battery will also clear the trouble code unless you have another problem. Therefore, you will not see an immediate DTC after replacement. --- Drive at least 5 miles with 2 stops - stopping means turning off the engine and removing the key. If you still don't get a DTC, you're probably fine. The same test failed for a month when I decided to replace the sensor. I have attached some photos showing exactly what I received.