Hot answers tagged

11

Lambda sensors, often referred to as oxygen sensors or O2 sensors, are the bedrock of any modern-day EFI system. Without them, fuel injection management is essentially flying blind and has to resort to other less-desirable means to determine how much air and fuel need to be mixed. Their primary role is to provide feedback to the fuel management to determine ...


9

It should hold up. It melts at around twice the temperature where water boils, which I don't think you'll ever experience in the engine bay (unless it's touching the exhaust). But the greasiness in the engine may make for a poor adhesion. BTW: I am one of those people who would rather crimp than solder.


7

No, you don't have to rely on wire colors to figure out what's what. With nothing more than a decent multimeter and premix flame (blowtorch or gas stove), a two-test sequence can reveal the identity of each wire, assuming the O2 sensor is fully-functional: Determine the heater wires This should be done first. These wires serve to heat up the O2 sensor ...


6

It was indeed the catalytic converter (the EX does not have a pre-cat). After replacing it, the downstream sensor graph spends most of its time above 0.5 V, as it should if the converter is working. Update: I started getting this error code again, a little over a year after replacing the cat. I also finally found a guide on how to read these graphs, from ...


6

If you are going to replace the sensor and have already purchased the replacement, cut the wires off of the old sensor and put a 1/2" drive deep well socket onto it (don't use the split socket for the O2 sensor to take it off, but you will use it to put it back on). Use a breaker bar to break it free, then use a ratchet the rest of the way. If you do not ...


6

Pending code? The user manual for your device says it should say "PD" for pending codes, so maybe not. "P0130 P" isn't a valid DTC for your vehicle so pending code is really all that makes sense. More specific to your model P0130 is front oxygen sensor circuit range/performance problem (Lean) Possible causes: Open wire to O2 Sensor Short to ground in O2 ...


5

Looking at the description of the California O2 sensor for your car, the only thing different on it (besides the internals) is the electrical plug. The wrench which you tighten it down with is 7/8", which means the sensor bung should be the same size as well. I don't think there is any real external difference between the California and non-California ...


5

In the perfect world, you just slide a wrench on the O2 sensor and it comes out. Unfortunately since its located in a "hostile" environment (lots of heat, lots of water and potential corrosion underneath) it typically gets pretty stuck, though most people eventually do have success getting it off. Careful not to start stripping it with that open ended ...


5

I doubt you're going to be able to have someone put a number on this. I'm betting you also know that just because no error was thrown, it doesn't mean that the sensor isn't impacting performance. Lifehacker notes that replacing them could improve mileage "up to 15%." As @BobCross mentioned, "most people wouldn't consider it worth their time to do the ...


5

It is most likely that this sensor has failed. The question is why does the MIL only come on above 70mph. The answer lies not in the sensor but how and when the sensor is tested by the PCM. Every sensor (and actuator) in the engine control system is tested by the software, but not all the time. Each sensor has its own set of test entry conditions; each OEM ...


4

The ECU may have "tuned" itself to the gap and behavior of the old plugs. When you had the plugs replaced, if the shop did not disconnect the battery (and even if they did, not sure about your Ford) the ECU would still have the long term fuel trims that matched your old plugs in effect. So this may result in a bit less or more fuel being injected and ...


4

Just to add to the other answer as I ran into this same issue, what kind of emissions do I have on my mitsubishi galant? I had this code: P0421 and I had to replace my O2 Sensor & the catalytic converter but I wasn't sure if I needed the CARB (California Air Resource Board) compliant ones or not. There is a label that identifies what type you have. I ...


4

From time to time you do come across a rusted in sensor. Your vehicle being a 2001, and O2 sensors lasting some time, yours is rusted in. If sheer force does not work you may need to use an oxy-acetalyne torch on the sensor to heat to it red-hot to break the rusting and undo it with a good single-hex deep socket. I have had one or two sensors break up and ...


4

Buy the correct O2 sensor, hacking up the OEM harness to put a different O2 sensor on the car is a bad idea.


4

With the check engine light on, the car is going to be running a fixed set of parameters from the Engine Control Module. For instance Fuel Pressure will be held at max pressure and timing and spark adjustments (if done electronically) will not retard or advance. One of the reasons this happens is because the Engine Control Module is not recieving all of ...


4

As @LynnCrumbling stated, this would be hard to put a number on, mainly because it depends on too many factors. This is what I can tell you. When O2 sensors get old, they don't necessarily go bad, what they do is get lazy. When a good O2 sensor is doing its thing, if you were to look at the readings from it, the numbers go all over the place, from top of the ...


4

Disconnect your battery to reset your ECU. It won't hurt, and is probably the cheapest and easiest thing you can try. 30 minutes is usually enough. There are other theories as to why your mileage went down, but I think you're on the right track thinking the ECU hasn't learned to use the new data correctly. I am thinking that because your new 02 sensor is ...


3

Also, remember that MAF is a reading of the amount of air entering the engine. If you have a backflow issues (high backpressure) or even a timing issue where the valves are not opening and closing at the correct time (slack chains, jumped timing), your MAF sensor readings will reflect this as well. I know this post is late, but any who are looking into this ...


3

I doubt your sensor requires soldering. I would recommend always going with OEM parts, as they ensure the values the sensor sends are accurate. Next, verify which sensor it is as some cars have 4 and are divided into banks (sides). The code should say which side you are looking at. The sensor itself might need a special socket, but that is not necessarily ...


3

A quick way to check your O2 sensor, is to record all the codes (On paper, or whatever) and swap the sensors. If the code goes to bank 2, than you know you need a sensor. These are sometimes hard to find, due to the many things that can trigger an O2 fault. This is just a quick way to check the sensors, just be sure to reset the codes after recording them.


3

Bank 1 Sensor 2 should be the sensor downstream of the catalytic converter. Bank 1 Sensor 1 would be upstream of the catalytic converter. With a 4 cylinder, everything should be Bank 1 (No Bank 2). So, Bank 1 Sensor 2 should be the one under the car. The one on/at the exhaust manifold should be Bank 1 Sensor 1. You might eyeball the wiring and / or ...


3

Replacing the broken fan switch seems to have made the CEL go away. My best guess is that the ECU starts monitoring the O2 sensor output as soon as this sensor reads that the engine is hot, and gets upset when the O2 sensor is actually still cold. Edit: Nope, the CEL is back, and gas mileage has been really bad (around 18-19mpg on a car that usually gets ...


3

A narrowband sensor can only measure 14.7:1 AFR (stoichiometric) , where as wideband sensors allows you to measure a range of AFR ~(<10 to ~20). ECU's that rely on narrowband output maintain the AFR at stoich by using closed loop control (cruise etc) and may use various interpolation methods for increasing the open loop accuracy for AFR other than stoich. ...


3

If the catalytic convertor is truly plugged, you wouldn't be able to drive the vehicle, so this makes me wonder about the voracity of your statement. With a plugged cat, the back pressure created behind it will only let you rev the engine to around 1500-2000 rpm. I had to replace a set of heads on a pick-up truck for a guy because he continued to run the ...


3

Root Cause: probably a couple of things Sadly, I feel that there isn't enough data here to uncover the smoking gun, but I have realized some things upon reflection that can indicate what is probably wrong with the vehicle: Question 1 If the front lambda sensor voltage is indicating rich, why is the fuel trim positive (indicating that the injector ...


3

Lambda sensors have several different failure modes. Heater element. The heater element is a resistive material that resists electron flow thus producing heat. This is the most common cause of early failure. The resistor burns through opening the circuit. Failure of the catalyst material. Usually caused by contaminates coming from the engine. Very ...


3

I haven't been able to find any solid conclusions on the VW forums regarding the root cause for this behavior, but there are some clues as to what could be causing this from the diagnostic code. Fred Wilson's answer remains a distinct possibility but I struggle to reason with why the engine computer would choose to throw a code/MIL for a bad sensor on a ...


3

There are currently two kinds of narrowband sensors used these days: titania sensors (NTK) and zirconia (Bosch). This answer only addresses the zirconia sensors which are the most common type. Referring to the diagram (which was created by Michael Handrich and shared under a Creative Commons license), the sensor is a galvanic cell that generates what's ...


2

From everything I see in this paper, it seems that it may be related to a vacuum leak. tl;dr - Check your vacuum lines and make sure none of them are cracked. Here are some more ideas from here: P2197 Lack of HO2S-21 Switch, Sensor Indicates Lean Detailed Description A heated oxygen sensor (HO2S) indicating lean at the end of a test is ...


2

I just had these exact symptoms with a 2002 Vauxhall Astra. As well as the Crankshaft Sensor error (and the garage confirmed it had previously thrown out an O2 sensor error). Mine was the EGR valve, with fuels that use a lot of additives (here in the UK that's 'supermarket fuel') the valve quickly becomes caked in carbon. The EGR (exhaust gas ...



Only top voted, non community-wiki answers of a minimum length are eligible