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7

Picture 1 is the downstream 02 sensor. Upstream is located on the exhaust manifold. Picture 1 contains both convertors. Picture 2 is the exhaust resonator.


6

Your data logs tell me the following: Fuel trims are fine Here are some plots I generated from your data for both short-term and long-term fuel trims. The plot above (Bank 1 STFT vs Bank 2 STFT) show that there is no bank imbalance and most of the data points hover around zero STFT correction, which tells me that feedback from the O2 sensors is ...


5

It should look something like the following picture. The flats for the wrench are at the bottom so you may not be able to see them depending on the location. They also might be covered by a heat shield. You use something like the tools pictured below to get it off.


4

Before suspecting a bad O2 sensor... You need to be sure that the replacement MAF is suitable for your car. You mention the replacement MAF is a 5-pin and not a 4-pin like the one originally on the car. If the new sensor has a different flow-voltage calibration this would go a long way to explain what you are seeing. This is because the onboard fuel ...


4

Upstream Variation (Hz) is also called O2 crosscounts, this normal fuel mixture control, the fuel computer changes mixture ever so slightly so it crosses the stoichiometric boundary (.45v), back and forth from lean to rich. The more crosscounts the better fuel control is and indication of a healthy O2 sensor, high crosscounts is also an indication the fuel ...


3

As @FredWilson pointed out, there is no relearn for a heater circuit code. On a 2.3 Check for power at the ECM connector C pin 13 (white). On a 3.0 Check for power at the ECM connector C pin 1 (black/white). While the o2 heater wire may have power there may be a break in the wire that goes to the ECM. This wire tells the ECM that the heater relay is ...


3

It sounds a lot to me like it could be your car's O2 (lambda) sensor in the exhaust. From wikipedia Oxygen sensor Function of a lambda probe Lambda probes are used to reduce vehicle emissions by ensuring that engines burn their fuel efficiently and cleanly Sensor failures Normally, the lifetime of an unheated sensor is about 30,000 to ...


2

Both pre and post catalyst "Oxygen" Sensors report exhaust fuel mixture to the PCM. So the PCM can and does use both to sense and adjust mixture. The rear sensor gives a better average mixture because the catalyst is a mixing chamber. In newer designs the rear sensor is used more for mixture sensing than the pre-cat sensor. In these designs a pre-cat Air ...


2

In answer to your last question, yes your car does have an o2 sensor, all modern cars do. Here are a few tips to pass an emissions test Drive the car on the freeway for at least 20 minutes before taking it in to get the emissions tested. If the engine is cool when you bring it in it won't burn as clean. Get a tune up. Replace the spark plugs, wires, and ...


1

Your graphs look very normal. No, the post cat sensor will remain a nearly flat line when the engine is a steady speed, if the catalyst is good. It can and likely will lean or rich as the PCM chooses its fuel control strategy. So steady voltages of .2 to .8 are normal. The catalyst acts as a homogenizer of fuel mixture so the rich to lean cycling seen ...



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