Failed Emission Test

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ccp1979

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Apr 20, 2019
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4
We bought a 2017 Rex in NJ but live in NY so we have to get the emissions tested for NY. Went to 2 different dealers today and neither one could figure it out!!! My husband put it in emissions mode. One guy said it needed to drive until Rex started. He did that. Still didn’t work. Next dealer said it needs to be driven 100 miles. No one seems to know!! Ugg any advice or help would be great!!
 
When your husband put in in emissions mode, didn't the Rex engine start? That should be all that is needed.
 
It did. And he just got home and told me there are codes that need to be cleared they said? And these can only be clearer by driving 100 miles. And after they clear it should work?
 
Ok, that means something was done to the car, where the 12 volt battery was disconnected. Without power, the car's computer has lost all its accumulation of diagnostic data, and and needs to rebuild this during the car's operation. Do a combo of idle, city, highway, short, long trips over a few days to let the car collect a new data set, then it should be ready to pass inspection. The OBD sensors (much like anything connected to the ECU) require self-calibration to function correctly, which requires driving around to complete that, if it has all been lost because of a battery disconnect.
 
My husband says - “That’s the most useful information I’ve had all day- thank you so much!!” That must be what happened. He’s wondering if you know- does the range extender also need to come on to rebuild the data?
 
That I'm not sure about, but it would not hurt to run the car down to the point that the Rex started, and let it run while driving for a bit. I know that the Rex starts up and runs a short maintenance cycle every 50 days or so automatically, if it hasn't been triggered and in use during that time, to keep it in good operating condition, so the car will be collecting running data on it.
 
One caution about disconnecting the 12V battery. I've not done this, yet, so I'm only sharing what I've read here.

There are reports that changing a 12V battery requires pairing it with the car. My only caution is disconnecting and reconnecting a 12V battery may trigger the battery repairing.

When I owned Prius, doing a 12V, power-on reset, cleared codes which sometimes was necessary. For example, trying to restart a Prius three times when it is out of gas sets a code that prevents further attempts even after adding gas. Doing a 12V power-on reset clears the code and the Prius starts.

For my 2014 BMW i3-REx, I use Bimmercode, an iPhone App, to read and clear codes using an iCab, OBD interface. But I caution that I've not done any 12V battery work ... yet.

Bob Wilson
 
changing a 12V battery requires pairing it with the car

Yes, replacing a 12V battery in a BMW with a new one requires that it be 'registered' with the car for best battery life and to avoid electrical issues. If you disconnect and reconnect the existing battery, however, it does not need to be re-registered, the existing registration info is recorded/stored/held in a solid-state memory chip, similar to what is in a thumb drive.

During the BMW battery registration process, the following happens:
- Battery capacity is set to 80%
- Current Odometer reading is stored
- Stored battery statistics such as: current, voltage, battery charge level, are deleted.
- Stored temperature statistics are deleted

The BMW battery management software uses this stored data, and data it collects, to set and adjust optimum charging levels for the battery over time.
 
MKH said:
. . . the existing registration info is recorded/stored/held in a solid-state memory chip, similar to what is in a thumb drive. . . .
Is the memory chip part of the battery or something part of the car?

Thanks,
Bob Wilson
 
Is the memory chip part of the battery or something part of the car?

It is part of the car, a small module called the 'Intelligent Battery Sensor", which is located on the negative battery cable near where the cable attaches to the negative battery post.
 

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Thank you!

A side question, do you know the maximum amp rating of the traction battery-to-12V battery?

The reason I ask is my first Prius modification was to install a 1.1 kW, 12V-to-110VAC inverter. Testing revealed it could draw ~70A before we saw a 12V dip. We used it as our emergency generator for years until I was able to install a 16kW, permanent, natural gas, emergency generator.

http://hiwaay.net/~bzwilson/prius/priups.html

Bob Wilson
 
do you know the maximum amp rating of the traction battery-to-12V battery

No, but here is a link to a BMW training manual on the car's High Voltage systems. Might be some info gleaned from it.

https://cdn.jack.sh/2014/08/06_I01-High-voltage-Components.pdf
 
That document states:
The EME control unit communicates with the EDME control unit, in which
the 12 V power management functions are performed. The result is the setpoint value specification for
the voltage, which the DC/DC converter should adjust in the low-voltage vehicle electrical system. The
continuous output power of the DC/DC converter is 2500 W.
However I would hate to damage it so it might be worth derating a bit.
-Tim
 
I had the same issue in NY. Once the Rex engine has run for enough time, the emissions test will pass WITHOUT the rex running at the time of inspection. The easiest thing is to run down the battery and continue to drive around on rex power. Then go back to the inspection station.

Also, according to the training manual the HV-to-12v converter can supply 2500 watts continuously.
 
I live in Massachusetts and we took delivery of our 2015 I3 REX about a month ago with a State Rejection Sticker on it. The dealer explained it needed to be driven about 150 miles and the Rejection Sticker was good for 60 days. I put about 400 miles on it and went to my normal inspection station, I explained the situation and was also armed with the instructions on how to put the car in Emissions Mode. They were confident this was not necessary and evidently it wasn't. They connected the car to the State online system and immediately everything cleared and it passed, wahooooo! My thoughts are that "Failed Emissions Test" is a figure of speech and they don't have another explanation. I recommend you put some miles on it and take it in for the test judging from my experience. Good Luck and get out and have fun with your i3!!
 
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