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O2 Sensor CEL and emissions test

4 May 2008
I bought my car about a month ago in Ontario, CA. When I bought the car I drove it around for about 2 weeks including a 2 hr trip to Montreal. No issues. Then I had the car shipped by train to Vancouver. In Vancouver it sat for about 3 days in the rain before I was able to pick it up. When I picked up the car and turned it on I got a CEL and took it to the nearest auto shop to get the code pulled. The code is P0141 - O2 Sensor Heater Curcuit (Bank 1 Sensor 2). They reset the code and I drove the car another 3 hrs home without issue. The next day I started the car and the CEL came back, it's the same code. I see that I can buy new O2 sensors from SOS for cheaper and everything. That may take some time and I'm eager to get the car registered. To register the car for title and plates I need an emissions test. Any chance I could pass an emissions test if I reset the code for now?

TLDR: Can I pass an emissions test if I reset the code?
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No, at least here in the US, you cannot. Resetting the ECU, wipes out the self tests, which require 50-100 miles to clear. In the US when they scan the car if these tests are not ready= fail!!

This code is typically immediate, so it does make me wonder if you have a connector issue with that 02 sensor. The "heater" is like a lightbulb, so I find it hard the actual 02 sensor is intermittent. Could be, but a little odd. Check the connectors by the rear valve cover, lower passenger side. Make sure they are tight, and check the male connector to see if a pin is loose.

Depending on your state and model year, not all readiness checks need to be complete. In Virginia, for a 2000, up to two readiness checks may be incomplete. I believe for 2001+, that changes to only one that may be incomplete.

It would be a tricky dance to try and time it right though. Especially given Larry's point about how fast that code tends to show up (i.e., how quickly the readiness check is completed).
Thanks! I ended up ordering 2 new sensors from Amazon (Denso 234-4621 and 234-4093), unfortunately only one showed up (4621) before the weekend so I didn't install them yet. I will check the connectivity first though. I have one of those cheap OBDII Bluetooth scanners.
I have one of those cheap OBDII Bluetooth scanners.

May be cheap, but totally awesome tool:). Mine supports all 7 Auto Technologies, and now I keep it in the glove box of my daily driver, so I can immediately scan a car if someone asks for help.

Which one do you have Larry and what app do you use? I have the ELM327 and I've been using the Torque app on Android, but I have an iPhone now and need a Wifi one and need an iOS app recommendation.

BTW I changed my O2 Sensor (Bank 1 Sensor 2) with the Denso 234-4093 and so far so good. The replacement cable was a little longer so there is some extra cabling. I need to get some high temperature tape to secure the cable to the little guide bracket like it was before. I will probably jack the car back up and replace the other sensor (234-4621) since I already bought it.
... I have an iPhone now and need a Wifi one and need an iOS app recommendation.

The GoPoint BT1 is kind of the standard and another option is the Automatic (though it has an authentication routine that can be fussy from what I gather) but if you can wait a bit, the Kiwi 3 will be available. They are shipping the first round through Kickstarter. It is BTLE and so should be more straightforward. It's also very small.

DashCommand seems to be a good app for iOS. It has helped me a ton.
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Thanks guys, I will probably wait for the Kiwi as I still have my old android phone to use with the ODBII adapter for now.

I also completed my emissions test today without any issues.