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I don’t think the cause of the failure will make any difference in diagnosis. I don’t believe it really matters HOW it fails, you could still use these methods to diagnose a bad converter. That said, you should address the root cause or your new converter will suffer the same fate as your old one. It is true that you need to address any engine performance issues before you replace a converter. If not, it will be a very expensive lesson.
Thanks for your input.
Hi Eric, in regards to your video about diagnosing a P0420 code, I have the same problem and used a OBD2 scanner to read data from the O2 sensors.
On bank 1, and revving around 2k RPM, the pre-cat O2 sensor was moving from low to high values back and forth like you said it should be doing, but as far as the post-cat sensor, it was staying around .9V which is quite different from what you had on your scanner for a bad cat. What would this mean in my case?
Thank you for your time
[quote=”Wiglud” post=94483]Hi Eric, in regards to your video about diagnosing a P0420 code, I have the same problem and used a OBD2 scanner to read data from the O2 sensors.
On bank 1, and revving around 2k RPM, the pre-cat O2 sensor was moving from low to high values back and forth like you said it should be doing, but as far as the post-cat sensor, it was staying around .9V which is quite different from what you had on your scanner for a bad cat. What would this mean in my case?
Thank you for your time[/quote]
It might mean a bad O2. You might also want to check the temps as shown in the video to verify the catalytic converter operation. If it’s operational, then that could verify an O2 sensor problem. Mostly with a P0420 it’s the catalytic converter and not the O2 sensor that’s at fault.
Any idea how the O2 sensor data would look with a pre-cat exhaust leak?
My 2004 Subaru legacy has a manifold mismatch due to an engine swap. It’s the California emissions version, so I have three cats and 5 O2 sensors (2 are A/F). I can read OBDII with RomRaider and/or Torque.
I bought a junkyard header and I’m headed to a muffler shop this week, but I’m hoping it’s not actually the cats. Thanks!
[quote=”Joeboo25″ post=114169]Any idea how the O2 sensor data would look with a pre-cat exhaust leak?
My 2004 Subaru legacy has a manifold mismatch due to an engine swap. It’s the California emissions version, so I have three cats and 5 O2 sensors (2 are A/F). I can read OBDII with RomRaider and/or Torque.
I bought a junkyard header and I’m headed to a muffler shop this week, but I’m hoping it’s not actually the cats. Thanks![/quote]
You can always check the temperature of the cats to see if they function like in the video. That’s the way we did it before OBDII.
Yeah, I think that’s the next step and I already have an IR thermometer. I’m hoping the manifold swap will normalize my sensor data. But even if it does, I’m still taking the temperature because it’s such a neat test.
Wait till you see the new toy I got today in action. It will be a bit before I do the review, but when I do, I’ll be headed strait for some cats to try it out on.
My CHECK ENGINE light is ON and I am getting the following error codes on my Ford Explorer 2013 please suggest how to fix them:
Powertrain Control Module:
(1) P0420:00-68 Catalyst System Efficiency Less Than Threshold – Bank #1
(2) P0430:00-EC Catalyst System Efficiency Less Than Threshold – Bank #2
(3) P2196:0028 O2 Sensor Signal Biased/Stuck Rich – Bank 1, Sensor 1
(4) P2198:0028 O2 Sensor Signal Biased/Stuck Rich – Bank 2, Sensor 1HVAC:
(1) U0140:00-08 Missing Communication with BCMRCM:
(1) U0557:82-08 Invalid Data Recieved From Front Control Interface Module AI will be very thankful to you for your kind help and reply.
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