hi,

Can anyone help me with this code P0141 - H02S S2 Heater Circuit Malfunction Secondary heated Oxygen sensor. I have had this for 2 months now the check engine light comes on and goes off dealership recommended replacing the Secondary o2 sensor. When I went to buy this part from a auto parts dealer he was not sure and said there are two secondary sensors not sure which one to buy. Any advise on which one to replace and how can I get it done without spending like 500 $ at the dealership.

Thanks

Aman

 

If this is a 4-cylinder or V6 for that matter there is only 1 secondary O2 sensor (behind the catalytic converter). Your code indicates a fault in the heater circuit (short or open). Most likely is an open circuit due to faulty heater element in the sensor. Diagnostic (check O2 sensor element resistance) is necessary to confirm faulty sensor.

good luck

 

First post, so WELCOME to HAF!

First things first. Congratulations for telling us that its a 2004 Accord. Now open the hood & try to figure out HOW MANY CYLINDERS it has.

The 4-cyl car has 2 oxygen sensors. Primary is in the exhaust pipe before the catalyst (see from underneath, between engine & firewall. Secondary isin the back part of the catalyst. Sorta below the shift lever.

I think you may have to remove the passenger seat & pull up some carpeting to find where you can unplug that sensor. (Who designed that anyway?!?) Got a multi-meter? Take the wire from the sensor itself, & measure resistance between the 2 same-color (black?) wires. I think it should be 5 or 10 ohms. Most common reason for that code is the heater will measure open-circuit. If so, you need a new sensor.

Get one at anauto-parts store for a lot less than $400.

Remember to support the car properly before crawling underneath. Use some real jack-stands, notthe tire-changing jack.

If the sensor preheatermeasures OK, then you have to troubleshoot the circuit that powers that heater.

If you have a V-6, the story is probably similar, but Im not sure about the details.

 

Thanks Jim, well it is a Honda V4 and I am thinking of getting the new sensor installed from my mechanic will buy it and then he can install, do u still think I should check the preheater etc or the new sensor will take care of everything. Also read somewhere that after installing shoule reset my ECM so that teh engine light does not pop up again. Also the Honda dealre has also recommended a new sensor let me know your thoughts and Thanks again for your quick feedback.

Aman

 

(Its an in-line 4-cylinder engine, not a V-4.)

If the real problem is a broken wire in the car, your sensor-heater will measure OK. In that case a new sensor wont fix it. OTOH, a new sensor wont hurt either.Some mechanics will put a new sensor in (to make the profit on parts cost) & then fix the wire on the car.

Either way, check whether your mechanic will install a new sensor that YOU buy. Part of the money he makes is profit on parts sales. Lets face it, whatever you do for a living, you dont do it for free either...

Reset the ECM. If you dont, the engine light will stay on for several driving cycles before going out by itself. Its slightlybetter to reset so the ECM is forced to learn the behavior of the new sensor.

 

Thanks how long can I wait before I get the secondary O2 sesor replaced as it is an intermittent code the engine light comes and goes away. is it ok to have it replaced during my next oil change which is not due until feb my mechanic said all it will do is bring my mileage down but would not hurt the engine substantially . waht do you reccommend does it have to be replaced instantly or can I wait for sometime it has already been more than a month since the code first showed up.

aman

 

The secondary O2 sensor has no impact on engine fuel metering. It's only function is to monitor performance of the catalytic converter. If you don't mind the CEL on all the time, it can wait.

good luck