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I have 2004 honda accord 2.4 liter w/ “check engine” light on. I went to auto shop that had OBD code reader. code is “p0141 bank 1 sensor 2” which is O2 sensor. I checked youtube & ETCG vidds and found out there is more than one O2 sensor (upstream, downstream, pre-catalytic converter, in catalytic converter, one in the engine compartment at exhaust manifold). HELP? how do I determine which one is bad?
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you first have to determine if its bad. the code indicates the reading is out of range, which could be lean or rich mixture, or the unit itself. is there any symptoms with the vehicle? when was the last tune up done?
[quote=”JakeVA” post=75505]I have 2004 honda accord 2.4 liter w/ “check engine” light on. I went to auto shop that had OBD code reader. code is “p0141 bank 1 sensor 2” which is O2 sensor. I checked youtube & ETCG vidds and found out there is more than one O2 sensor (upstream, downstream, pre-catalytic converter, in catalytic converter, one in the engine compartment at exhaust manifold). HELP? how do I determine which one is bad?[/quote]
Since your engine is a 4 cylinder, normally there is only “bank 1” Sensor 2 usually refers to the post-cat (after the converter) sensor. So likely your code is for the O2 sensor located behind the converter.
BUT, and a big but, Shaun is dead on. Just because you have a O2 code does not mean the O2 is bad. It just means the readings are out of normal specifications. You could have an air leak somewhere in the exhaust or a bad converter or fuel trims out of whack throwing off the reading.
Thanks for your responses. There are no troubles w/ the car; or performance issues. autozone clerk said vehicle will not pass Virginia State Emissions w/ “check engine” light on, and underlying issue will probably cause it to fail the vehicle when hooked up to emissions tester.
The car belongs to my g/f and she is not observant about performance issues; she has no information on gas mileage change; different odors; etc…. I have little history driving the car and cannot comment on change. The car starts fine and acceleration appears normal. There is no noise from leaky exhaust.
Last tune up? I just changed plugs & air filter (car has 142K) but the indicator light remains on. g/f has no information about service records.?? O2 sensor post the catalytic converter?? I easily found the one mounted in the converter and followed the lead to it’s location under the RF seat- exactly as ETCG video shows. The wiring is two black, one blue, one white.
ETCG vid shows replacing the sensor and talks about testing it w/ OHM meter, which I do not own. I can probably get my hands on an OHM meter, but vid does not show how to test the sensor. ETCG only shows the one sensor in the catalytic converter. ETCG does not say if sensor in the video is “upstream, downstream, post-cat, etc…”
“college man” Yep. that is exact sensor location & wiring path ETCG shows in the video and that is on the vehicle. The sensor cost ranges from $99 Bosch, $149 Denso, $239 NGK + $20 for “O2 sensor socket” (socket costs too little for autozone to rent/loan)…. I would like to know I am replacing the correct sensor before spending that money.
Thanks again for the responses.
Anyone have details/ instructions on how ETCG used the ohm meter to test the sensor?
I not positive about Honda, but have you tried clearing the code and see if it comes back? can’t remember off hand if an o2 issue gets stored in memory and needs to be cleared or not. that’s alot to pay if its not the problem. you need to put it on a live scanner and watch the variables while you purposly give it lean and rich mixtures and see how the sensor responds.
I recently diagnosed and replaced a bad AFR sensor on my car. Like the other posters alluded to, an outlier reading can generate an error code or you may also have a pending code in memory. Clear the codes and see if they reappear.
Also, many ODBII code readers give a generic description with an error code and Honda will have a more specific description, which was more helpful in my case. The Helms manual for my car (TSX) states that a P0141 is a malfunction with the heater circuit in the secondary heated O2 sensor – I don’t know if this applies to your car or not however.
If the above is true, then Eric’s video shows you how to diagnose a faulty heater circuit with a multimeter. The black leads go to the heating element while the blue and white wires go to the O2 sensor. Measure the resistance between the black leads. If the heating element is good, the resistance should be on the order of tens of Ohms. A bad heating element will have a resistance 100 kOhms or higher because no current can flow through the heater, and a code is generated because the emission system is not operating at some prescribed level.
Finally, if the O2 sensor requires replacement, try to use a direct replacment. From what I’ve read for my car, Hondas can have issues with universal sensors, especially the ULEV models. You might want to consider the Denso or NGK part (whomever made the OEM part for your car).
[quote=”Hanneman” post=75645]
Finally, if the O2 sensor requires replacement, try to use a direct replacment. From what I’ve read for my car, Hondas can have issues with universal sensors, especially the ULEV models. You might want to consider the Denso or NGK part (whomever made the OEM part for your car).[/quote]Thanks for bringing that up
Any O2 that you have to wire in manually (universal style) I wont touch here in the shop, they cause far more problems than they solve. The butt connectors are prone to corrode (especially rear O2s as the wring is often under the car) and will actually make a sensor lazy or out of range and sometimes wont set a code.
Thanks for bringing that up
Any O2 that you have to wire in manually (universal style) I wont touch here in the shop, they cause far more problems than they solve. The butt connectors are prone to corrode (especially rear O2s as the wring is often under the car) and will actually make a sensor lazy or out of range and sometimes wont set a code.
From what I read, there was a very specific procedure for splicing the connector, but I don’t understand the reasoning behind it. Also, many vendors won’t allow you to return a sensor that has been taken out of the box. So, spending more upfront may save you both money and frustration in the long run.
Just for clarification, I did not mean that the part has to be purchased from the dealership. I meant to buy an aftermarket sensor that is labelled “OEM style” or “direct replacement”.
FANTASTIC how fast you’all respond.
1. How do I “clear the code?”
2. Yep. ETCG & other site strongly encourage OEM direct replacement sensors.I will be at the car next weekend and attempt testing w/ multimeter & replace sensor if necessary.
Most ODB code readers, like the loaner units available at auto parts stores, have an erase function.
In the past, you could disconnect the negative battery terminal for several minutes to reset the system. I don’t know if this method still works. Just make sure you have the radio unlock code first.
The group is right, just because you have an O2 sensor code, that doesn’t mean that you have a bad O2 sensor. While you’re waiting to do your testing you could also check for vacuum leaks and also check the basic items on the engine. These videos might also be helpful.
This article might also help.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
banana:
Thanks again for all who replied – some appeared too complicated (just trying to make an omelet, not a soufflé). After watching ETCG vid saying “9 out 10 times the O2 sensor is bad…” but he went on how to check the wiring. I spoke to another guy and he said same thing. “if you haven’t done anything to the car’s wiring, exhaust, etc and CHECK ENGINE light popped on it’s gonna be the sensor- especially w/ 120K+ miles. I played the odds and just replaced the O2 sensor.I bought the DENSO sensor which is direct fit. After coming back from parts store, I sprayed some WD Blue Torch on sensor at cat converter. I had quick snack, sprayed a little more and got to work. It came off w/o ANY issue. DENSO included some copper color anti-sieze, which I used. A little wiggling to get the threads started, but it finally went in. Tightened w/o problem I had disconnect the battery negative cable to reset the code. I d/c’d the cable and then reconnected. Light remained on. I called my friend who said to d/c the cable for a couple minutes, THEN re-connect. This worked. ALL went well. Light went out.
Hanneman gave same suggestion. THX !!Fun getting “hands dirty” and saved a bunch $ and time.
Look forward to next task. Hopefully, it won’t be roadside emergency and I will have access to tools, garage, and ETCG vids !!
Peace
JakeP0141 OBD code. for Honda 2004, 2.4 litre = “in catalytic converter”
[quote=”JakeVA” post=76473]banana:
Thanks again for all who replied – some appeared too complicated (just trying to make an omelet, not a soufflé). After watching ETCG vid saying “9 out 10 times the O2 sensor is bad…” but he went on how to check the wiring. I spoke to another guy and he said same thing. “if you haven’t done anything to the car’s wiring, exhaust, etc and CHECK ENGINE light popped on it’s gonna be the sensor- especially w/ 120K+ miles. I played the odds and just replaced the O2 sensor.
[/quote]Very good.
One thing you have to keep in mind on here is many of us are repair techs. It is one of the mechanics ten commandments to verify all failures before replacing a part. For a DIYer it is sometimes cheaper to replace a part than to buy special equipment to test that part. For a shop tech it is a good way to get fired or loose a customer.
We have to be real careful of everything we do and even advise. A local shop years ago found itself in a nasty lawsuit. A lady called the shop and explained her oil light had just come on. The technician told her the pressure switch that runs the light was likely bad. She asked if it was drive-able and the tech said “most likely”. She attempted to drive it into town and the engine seized up. She had it towed to the dealer in Nashville (BMW) and had the engine replaced and sued the shop for the cost. She won as the judge felt the techs should have gave the exact same advise her manual does, which is to have to towed to a repair facility.
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