Honda Clarity Forum banner
1 - 7 of 7 Posts

·
Registered
2018 PHEV Touring Atlanta, GA
Joined
·
1,080 Posts
Discussion Starter · #1 ·
Although modern emissions testing is done by reading previously recorded data from the computer via the OBD-II port, in some cases the tech will also need to start the gas engine for about a minute so that the computer can check that all of the emissions equipment is functioning.

For gasoline cars this is of course no problem. But hybrids don't always want to start the gas engine "on cue". However there are two ways to start the Clarity engine in this situation. The first and simplest method is to make sure that the HV battery is less than half full when you take your car in for the emissions test. Then if the tech asks you to start the engine, all you have to do is turn the car on and activate HV Charge, which is done by pressing and holding the HV button for a few seconds. In most cases the gas engine will start right up.

In case that doesn't work, or if the HV battery is more than half full, then you can put the car into maintenance mode. It's not that hard to do, but there are multiple steps and the first time you do it it can be difficult to accomplish all of the required steps in the allotted sixty seconds. So it's best to try it once or twice before going in for the emissions test. And be sure to have the steps handy either on your phone or in printed form, because it can be hard to do the whole thing from memory. Especially with an emissions tech staring at you while other cars are lined up behind you waiting their turn.

These steps seem to be standard for all Toyota and Honda hybrids, so there may be some emissions techs who already know how to do it, but mine didn't when I took my Clarity in for its first smog check. Also these steps can come in handy when doing your own oil change, since a standard procedure when changing the oil and filter is to start the engine afterwards and check for any leaks.

Maintenance Mode
Once started the following steps must all be performed within sixty seconds. The first time you try it, since you likely will be reading the instructions while you are doing it you may exceed sixty seconds and it won't work. If that happens then just start from the beginning and try it again.

1) Make sure the car is completely off.
2) Without stepping on the brake pedal, press the power button (Accessory Mode).
3) Press the power button again without stepping on the brake pedal so that the instrument panel display comes on (ON mode)
4) Press the accelerator pedal to the floor twice.
5) Press the brake pedal and press the N button to put the car into neutral, then release the brake pedal.
6) Press the accelerator pedal to the floor twice.
Note - during this accelerator press it will beep and a message will appear:
"Gear Position is N, Release Accelerator Pedal". You can ignore this message.
7) Press the brake pedal and press the P button to put the car into park, then release the brake pedal.
8) Press the accelerator pedal to the floor twice. "Maintenance Mode" appears on the display.
9) Press the brake pedal and press the power button. The engine will start after a few seconds.

Do not drive while in maintenance mode. When you are done with maintenance mode, press the power button to turn the car off. After turning off the car you can then turn it on again normally.
 

·
Registered
Joined
·
660 Posts
At least Colorado doesn't require a tailpipe check for PHEVs. We get just the ODBII readings. Gas first cars (includes traditional hybrids) require a tailpipe emissions test.
 
  • Like
Reactions: Madmartigen

·
Registered
2021 PHEV Touring HB, CA
Joined
·
653 Posts
Although modern emissions testing is done by reading previously recorded data from the computer via the OBD-II port, in some cases the tech will also need to start the gas engine for about a minute so that the computer can check that all of the emissions equipment is functioning.

For gasoline cars this is of course no problem. But hybrids don't always want to start the gas engine "on cue". However there are two ways to start the Clarity engine in this situation. The first and simplest method is to make sure that the HV battery is less than half full when you take your car in for the emissions test. Then if the tech asks you to start the engine, all you have to do is turn the car on and activate HV Charge, which is done by pressing and holding the HV button for a few seconds. In most cases the gas engine will start right up.

In case that doesn't work, or if the HV battery is more than half full, then you can put the car into maintenance mode. It's not that hard to do, but there are multiple steps and the first time you do it it can be difficult to accomplish all of the required steps in the allotted sixty seconds. So it's best to try it once or twice before going in for the emissions test. And be sure to have the steps handy either on your phone or in printed form, because it can be hard to do the whole thing from memory. Especially with an emissions tech staring at you while other cars are lined up behind you waiting their turn.

These steps seem to be standard for all Toyota and Honda hybrids, so there may be some emissions techs who already know how to do it, but mine didn't when I took my Clarity in for its first smog check. Also these steps can come in handy when doing your own oil change, since a standard procedure when changing the oil and filter is to start the engine afterwards and check for any leaks.

Maintenance Mode
Once started the following steps must all be performed within sixty seconds. The first time you try it, since you likely will be reading the instructions while you are doing it you may exceed sixty seconds and it won't work. If that happens then just start from the beginning and try it again.

1) Make sure the car is completely off.
2) Without stepping on the brake pedal, press the power button (Accessory Mode).
3) Press the power button again without stepping on the brake pedal so that the instrument panel display comes on (ON mode)
4) Press the accelerator pedal to the floor twice.
5) Press the brake pedal and press the N button to put the car into neutral, then release the brake pedal.
6) Press the accelerator pedal to the floor twice.
Note - during this accelerator press it will beep and a message will appear:
"Gear Position is N, Release Accelerator Pedal". You can ignore this message.
7) Press the brake pedal and press the P button to put the car into park, then release the brake pedal.
8) Press the accelerator pedal to the floor twice. "Maintenance Mode" appears on the display.
9) Press the brake pedal and press the power button. The engine will start after a few seconds.

Do not drive while in maintenance mode. When you are done with maintenance mode, press the power button to turn the car off. After turning off the car you can then turn it on again normally.
CA dropped the tailpipe sniffer for more modern vehicles, at least back to 2008.

Interestingly, the Chevy Volt family will turn on the ICE any time the hood is opened while the vehicle is "on". The smog test tech has to open the hood to do the visual inspection, anyway.
 

·
Registered
2018 PHEV Touring Atlanta, GA
Joined
·
1,080 Posts
Discussion Starter · #4 ·
CA dropped the tailpipe sniffer for more modern vehicles, at least back to 2008.
Technically the need for tailpipe sniffing ended with the introduction of OBD-II in 1996 and newer cars. OBD-II was designed specifically to provide standardized emissions testing, although car manufacturers now also use it for other purposes. I know that as recently as ten years ago California still had some areas that required tailpipe sniffing even for 1996 and newer cars. I didn't realize that is still the case for some of the older post-1996 models.

Tailpipe sniffing requires not only the engine to be started, but for the car to be run on a dynamometer at a certain RPM. The emissions test facility that I go to here in Georgia still has their old dynamometer embedded into the floor, last time I was in I asked the shop owner about it and he said that it's a boat anchor now, they haven't used it since last year when 1995 model cars reached the exemption age of twenty-five years. But he said it would be too expensive to remove it. But he said they still have to briefly start the engine on all cars even new ones so that the computer can make sure that the various smog equipment is up and running. Doesn't make sense to me, seems like if any equipment wasn't functioning it would store a DTC, but maybe there are some hypothetical situations when it might not. Maybe that is what California is thinking also, maybe they don't fully trust the "self-reporting" on some of the older cars.

I think some places may still use a sniffer to check the seal on the gas cap.

Gas first cars (includes traditional hybrids) require a tailpipe emissions test.
For some reason I thought California was the last holdout.
 

·
Registered
2018 PHEV Touring Atlanta, GA
Joined
·
1,080 Posts
Discussion Starter · #6 ·
Interesting that tailpipe testing is still required in some places even for newer vehicles, it certainly adds cost and time to the testing. When I used to take my older car in for testing, the emissions station had a waiting room that you could sit in while your car was being tested, since it could take ten to fifteen minutes. They had a small TV and some magazines, and I remember sitting in there and listening to my car running through the tests on the dynamometer.

I don't doubt that CA and CO have a reason for wanting tailpipe testing in addition to OBD-II, but I just wonder what the reason is. From what I understand OBD-II is just checking that the emissions equipment is installed and functioning. Most states seem to accept that if the equipment is working then it's doing its job. CA and CO have a different attitude about it. I wonder if they actually have come across significant numbers of cars that have seemingly functioning equipment but still have emissions that are out of limits. Or I wonder if they are just data gathering to see how the different manufacturer emissions systems are working on particular vehicles. Perhaps it's for both reasons.
 

·
Registered
Joined
·
660 Posts
Technically the need for tailpipe sniffing ended with the introduction of OBD-II in 1996 and newer cars. OBD-II was designed specifically to provide standardized emissions testing, although car manufacturers now also use it for other purposes. I know that as recently as ten years ago California still had some areas that required tailpipe sniffing even for 1996 and newer cars. I didn't realize that is still the case for some of the older post-1996 models.

Tailpipe sniffing requires not only the engine to be started, but for the car to be run on a dynamometer at a certain RPM. The emissions test facility that I go to here in Georgia still has their old dynamometer embedded into the floor, last time I was in I asked the shop owner about it and he said that it's a boat anchor now, they haven't used it since last year when 1995 model cars reached the exemption age of twenty-five years. But he said it would be too expensive to remove it. But he said they still have to briefly start the engine on all cars even new ones so that the computer can make sure that the various smog equipment is up and running. Doesn't make sense to me, seems like if any equipment wasn't functioning it would store a DTC, but maybe there are some hypothetical situations when it might not. Maybe that is what California is thinking also, maybe they don't fully trust the "self-reporting" on some of the older cars.

I think some places may still use a sniffer to check the seal on the gas cap.


For some reason I thought California was the last holdout.
I think the tailpipe test is required to meet EPA standards in those areas that have significant smog and air quality issues. In Colorado, this is the Front Range from Pueblo to Ft Collins. The rest of the state doesn't have tailpipe testing.
 
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top