On a scenic drive today my MIL light came on...
Reset it by pulling the negative cable, (now know to use the "back up" fuse)
All was well for a good distance and then on she came again... Had a friend run diagnostics on it when I got back in town, "bad secondary oxygen sensor"

So my questions
Can I wire in a resistor and just not worry about it? Test pipe time...
If so, what ohms resistor would I need?? Or is there already a kit out there w/ a factory plug that will just plug in? (recall seeing one before on the Honda I know BBK makes one for Fords)
Jp

Secondly the warranty on any emissions piece is 7 years/150,000 miles correct? Possibly a free repair at the dealer...

 

[QUOTE]Can I wire in a resistor and just not worry about it?

 

It's the secondary one, the one in the cat.

 

The convertor and PCM are the only items covered to 8/80. If you are in California they have CA only emmisions warranty on other items beside the PCM and convertor.

Chances are, the code is a P0141 (HO2S2 heater failure) This code is only for the heater function of the sensor, not the sensors generated output signal.

There are no available plug in 02 simulators that also simulate the 02 heater.

A resistor can be wired to the heater circuit, but it must be rated for 10watts, 13ohms.

If the DTC was anything but a P0141, you may have another problem all together.

Moving to UTH

 

[QUOTE=Slows2k,Oct 29 2005, 10:39 PM]Chances are, the code is a P0141 (HO2S2 heater failure) This code is only for the heater function of the sensor, not the sensors generated output signal.

There are no available plug in 02 simulators that also simulate the 02 heater.

A resistor can be wired to the heater circuit, but it must be rated for 10watts, 13ohms.

 

I just checked the list of codes in the Helm manual. There is no code that says "replace O2".

 

Most that are running a test pipe need a fully functional 02 sensor to do so. They are using a stacked set of spark plug anti-foulers to space the sensor away from the exhaust stream, thus reducing the exhaust that passes over the sensor, and "simulating" a 02 signal that is close enough to a functioning convertor that the PCM doesn't turn on the CEL.

The 02 must be fully functional to do so, both the heater element and the output signal.

The resistor places a load the PCM is expecting to see from a functioning 02 heater element, it doesn't give you the 02 output signal generated by the sensor.

Option 1: Buy a new 02 and keep the convertor to maybe fix your problem. (since we don't know the code, we don't know if the 02 sensor is definitely the cause)

Option 2: Buy a test pipe, and still need a good 02 sensor to use the anti-foulers to fool the PCM the convertor is still there.

Option 3: Use a resistor to fool the heater circuit, and find a electronic 02 output simulator (like the ECG/Ziptech electronic unit) and get a test pipe, or keep the convertor.

The ECG simulator needs to be wired to power and ground, 02 input signal, RPM and TPS signal as well. There is no Plug n Play simulator that does it all.

Be aware of any Local /federal laws prohibiting removing the Convertor before doing so.

 

No, of course there is no code that states "replace 02", the OBD scan tool we were using stated "replace 02" as a possible correction for the actual code the scanner pulled. He paid damn good money for the contraption, computer wise it will do just about everything but fix the actual problem!!

I just spoke w/ my friend and he corrected me, the scan tool reported the MIL as a cat/02 effecieny code I believe a P0420, and also a Secondary Circuit Low Response or low voltage I believe a P0139 or P0137.

He stated that he more than likely believed it was the 02 and that would be the best place to start. He's ordering me one in the AM and we will start from there.
I'm asking in here for more ideas to what would cause the code.

 

A P0420 is a faulty convertor. Most likey caused by the front catalyst bed breaking loose from the outer shell of the convertor. It's not caused by anything other than a bad convertor.

The 02 sensor may be smashed from the broken catalyst, just replacing the sensor isn't going to fix the bad convertor.

If you're under 80K, don't clear the code. Take it to the dealer to have the convertor replaced. If the sensor is smashed it will need to be replaced too.

 

Well upon refereing to my Helms, it states that if you have any code P0137 through P0141 along w/ a P0420 that you should troubleshoot those codes and clear them before attempting to troubleshoot the code HP0420.
The three issues to troubleshoot w/ a P0137 are
1~ check voltage of sensor, replace sensor
2~check for continuity, find/fix lack of continuity
3~check ECM, replace ECM

So wouldn't you believe that the 02 would be a better place to start then just taking it to the dealer? If it is the sensor, then I have saved my self some money. If it isn't the sensor I'm out nothing, my friend can hold on to or send the sensor back and I then can take it to the dealer for a new cat. Although if I take it to the dealer and it's not the cat, I'm out the $75 to $120 diagnostic fee for them to tell me I need a new 02 sensor.

I apologize for not stating the proper codes when I first posted. It wasn't as bad as stating "my car is broke" but it did leave a little room for speculation I could have eliminated.

Also if it is the cat, test pipe time.
As for "Be aware of any Local /federal laws prohibiting removing the Convertor before doing so" It's illegal in all states to run w/o a cat on ANY street driven vehicle that was so originally equipped. Although modifications in general all break some law or moral obligation to the environment.