sampson100

Yesterday my CEL came on so I went to Auto Zone to find out why. They said code P0141 came up (Secondary Heated O2 Sensor; Heater Circuit Malfunction). I've got several questions:

1. Does a "heater circuit malfunction" mean that I need to replace that O2 sensor or is the "heater circuit" seperate from the O2 sensor?

2. Roughly how much am I looking at to have this replaced?

3. This summer I had to replace my ECU due to my ac condensation drain being clogged and it overflowed into the ECU. I have read that this O2 sensor is connected to/talks with the ECU. Could these issues be realated? (ie: could faulty install of the new ECU led to the O2 sensor heater circuit frying out?)

4. I've read that this particular sensor is in/near the catalytic converter. I know that my catalytic converter heat sheild was failing and my muffler shop secured it with some quick welding. Could failure of the heat shield lead to the O2 sensor heater circuit fail? (If I don't fix this problem will the problem with the O2 sensor happen again?)

Thanks for any help you're able to provide!

sampson100

By the way, its a 2004 Honda Accord EX 4cyl.

thanks!

redbull-1

1. Normally the O2 sensor is the part triggering the trouble code. The same code could come up related to something in the circuit, such as one of the wires cut; but, generally it is the sensor needing replacement.

2. Depends on whether your car is California or not and whether you will do it yourself.

3. Probably not. You have a new ECU, a short for a sensor may damage the ECU, not usually the other way around.

4. Probably not, unless the O2 sensor wired got chafed and eventually cut.

sampson100

thanks redbull. as for #2, it is not a California make as far as I know and I would not be doing it myself. Thanks again.

redbull-1

The Honda O2 sensor (non-Calif) part number is 36532-RAA-A02. Denso is usually the Honda OEM part, so it doesn't need to be bought from the dealer. Honda list price for the part if $92.05, internet discount price is approximately $67. You may be able to find it cheaper.

Denso is better than Bosch for Honda. You may want to read this thread:

https://honda-tech.com/forums/honda-accord-crosstour-2003-2012-118/2005-accord-lx-4cyl-2-4-engine-o2-sensor-2464806/

Standard labor should be around 0.4 hours, so depending on your area's shop rates, use that as a reasonable estimate. The only thing is some shop try to charge a diagnostic fee, which they may or may not apply toward the repair. Some shops won't if you already tell them you got that code and want the O2 sensor replaced. Talk to them first before agreeing on any work.

Targa250R

I've found that many Bosch oxygen sensor SKUs for Honda applications are actually re-boxed Denso or NTK parts. This is not the case for all sensors, but it's something to be aware of.

redbull-1

Good to know.

sampson100

Thanks for the help guys. I talked to my mechanic, told him the code that came up and he said I don't need to worry about it for a while. He said something about sometimes these will fail to warm up once and that will turn on my CEL. He said if I don't need an emissions test anytime soon that its something I can put off for a while. Any thoughts? I have read that this may reduce my fuel economy. Will this be drastic?

Thanks again for all your help!

Targa250R

It won't damage the car or affect driveability in any way. If it doesn't bother you to drive around with the Check Engine light on constantly, then sure, you can wait to replace it until your emission test is due.

You won't have any way to know if the PCM stores new error codes during that time though, since the light will already be on.

A Denso 234-4797 or Bosch 15409 sensor isn't expensive. If you're going to have to eventually replace it anyway for emissions compliance, you might as well do it now.

It sometimes can but it won't be drastic. Without the heater circuit working, the sensor is slower to reach operating temperature, but once it's heated up then it will work properly. Secondary oxygen sensors on most systems are simply there to monitor catalyst efficiency though and don't play a major role in fuel metering.