[knakkeow]

Hi everyone,

I had an issue on August 23, 2020, where the car slowed down and over-revved twice. Today, I took the car to the dealer this morning, and was told (1) Honda's Diagnostic tools could not find indications that an error or an issue occurred, (2) could not replicate the problem, and (3) without a diagnostic capture of the incident the dealership could do nothing about it.

After some research today, it seemed like others may be having similar issues. How were you able to (1) resolve the issue with Honda and (2) able to help document the Computer error code so the next time it happened?

Would anyone recommend an OBD tool that can monitor in real-time what "gear" the CVT is in, engine loading, speed, temp, and other parameters that may help isolate the problem while driving?

Here is what happened below:

(1) State of the car:
Car was in HV mode with 75% of battery, and not going uphill.

(2) Symptoms:
While driving or starting from a stop, the engine sounded like it shifted into a lower gear by the loud engine revving noises it made. It occurred twice.

(2a) Occurrence 1:
While driving at 35 miles an hour, the transmission sounded like it went to a lower gear, and the car was slowing down even after pressing on the gas. What seemed to address the problem was turning off HV mode, let it go into EV mode, then put it back into HV Mode.

(2b) Occurrence 2:
Between 10 to 20 minutes later. From a full stop at a stoplight, the transmission sounded like it was stuck in a lower gear, pressing the gas did not accelerate the car past 19 miles/hour. What seemed to address the problem was turning off HV mode, let it go into EV mode, then put it back into HV Mode.

In both cases, putting the car back into EV Mode, then back in HV mode, seemed to resolve the problem of the loss of power and engine over-rev. It seems odd to me that Honda would not have a fix for this yet.

 

[2002]

This seemed to be more common very early in Clarity production, reports like this are very rare now. What year is your Clarity, also what is the manufacture date (located on driver door jamb). How many miles on it, how long have you owned it?

Also not questioning what you experienced, but the more common issue reported (again mostly from a couple of years ago) is a very loud engine, some have described it as the engine is redlining. Based on these reports there may be some type of glitch that makes the RPM shoot up very high to an alarming level (although not harmful to the car), but most of that power is going to the battery not to the wheels, thus the sensation that the car has slipped out of gear (metaphorically as Clarity does not have gears, it doesn't even have a CVT). There is a theory that when this happens some people assume based on the sound that they are pressing the accelerator to near maximum so they don't press it any further, thus believing the car will not accelerate, when actually it would if they would have pressed the pedal farther.

Realistically it's difficult to gauge how far you are pressing the pedal, other than when the pedal is to the floor, most of us gauge accelerator pedal position by engine sounds or acceleration. So the theory again is that when people experience super excessive high RPMs, the pedal is only slightly pressed, enough to only barely maintain speed, but the high engine revs causes the driver to think they are pressing the pedal more than they really are, thus creating a sensation that the car will not accelerate.

Again not saying this was your situation, but do you remember if you tried pressing the pedal all the way to the floor? Any chance you glanced at the power gauge during this time? I understand if you didn't as an incident like this can be quite distracting, but it would be helpful if it happens again to watch the power gauge to see what it indicates during the high rev situation. In preparation you may want to watch the power gauge in normal driving perhaps more than you normally do and memorize what levels the power gauge indicates at different accelerations. Then if the incident happens again you will have something to compare it to.

As for an RPM gauge, there are relatively inexpensive OBD2 bluetooth devices that you use with a phone app. Torque Pro is a popular app, the free version will show RPM. Again it would be good to use it in regular driving and note typical RPM's, then if the incident happens again you will have something to compare to. This won't necessarily help solve it but it will give you more of a qualitative description to report to the dealer.

 

[60Hertz]

This does not directly respond to your issue, but this video is good background information that maybe will help visualize what might be happening under the hood when you are having this problem. If you have not seen it yet, it's a really good explanation of how the Honda PHEV drive train works in its various modes.

Problems like this that happen randomly and infrequently are a bear because it leaves no footprint and of course it never shows the problem when you take it to the shop. I wish you luck.

 

[lefty]

We had similar problems

with our 2018 Clarity Touring a number of times the first year we owned it. Sometimes it would happen in the winter during severe cold, other times in the mountains with a fully loaded car. Very disturbing and also terribly dangerous, so I filed a formal complaint with the National Traffic Safety Board. In reference to an earlier post, pushing the accelerator pedal to the floor does no good in those situations. I took it to our local Honda dealer and they exerted a good faith effort by hooking up a computer and driving with me but we couldn't duplicate the problem -- no surprise there. I considered using our state's Lemon Law due to safety concerns, but we haven't had any problems the last 1.5 years so decided to keep it. Am heading to the mountains again in a couple weeks so will be interested to see if we encounter the same problems again. I know of no solution, other than keeping your battery as fully charged as possible whenever in HV mode.

 

[2002]

with our 2018 Clarity Touring a number of times the first year we owned it. Sometimes it would happen in the winter during severe cold, other times in the mountains with a fully loaded car. Very disturbing and also terribly dangerous, so I filed a formal complaint with the National Traffic Safety Board. In reference to an earlier post, pushing the accelerator pedal to the floor does no good in those situations. I took it to our local Honda dealer and they exerted a good faith effort by hooking up a computer and driving with me but we couldn't duplicate the problem -- no surprise there. I considered using our state's Lemon Law due to safety concerns, but we haven't had any problems the last 1.5 years so decided to keep it. Am heading to the mountains again in a couple weeks so will be interested to see if we encounter the same problems again. I know of no solution, other than keeping your battery as fully charged as possible whenever in HV mode.

Thanks for the detailed info. I read all of the NHTSA reports a while back and I found eighteen that described a similar complaint, car would not accelerate, slowed down to 20 mph, etc. But most of them were from a couple of years ago there were very few recent reports. When I read the reports it sounded like what you experienced, in my opinion they couldn't all be explained by the high RPM theory where drivers are misled by alarmingly high RPM's into believing the car would not accelerate. Unfortunately none of the reports that I read specifically stated that they tried pressing the pedal to the floor, so there was no way to prove this wasn't the case to those who were dismissing the reports as just new owners who didn't understand how the car works. Although perhaps coincidentally I did notice that most of the reports were from people who had only owned the car for a relatively short time. It makes me wonder if perhaps the problem was a software glitch that somehow clears up as the car is driven longer and builds up more data. Or maybe the problem was fixed in a software patch that the owner may not have been aware occurred. Just guesses as a way to explain why the problem seems to have mostly gone away.

 

[knakkeow]

Thank you for your responses. The respones are helpful; I'm surprised Honda has not responded to this because it seems like a life safety issue. Imagine trying to figure out why your car is slowing down on the freeway from 65 miles an hour while you press the gas, and traffic around you is still doing 65. :crying:

This seemed to be more common very early in Clarity production, reports like this are very rare now. What year is your Clarity, also what is the manufacture date (located on driver door jamb). How many miles on it, how long have you owned it?

Also not questioning what you experienced, but the more common issue reported (again mostly from a couple of years ago) is a very loud engine, some have described it as the engine is redlining. Based on these reports there may be some type of glitch that makes the RPM shoot up very high to an alarming level (although not harmful to the car), but most of that power is going to the battery not to the wheels, thus the sensation that the car has slipped out of gear (metaphorically as Clarity does not have gears, it doesn't even have a CVT). There is a theory that when this happens some people assume based on the sound that they are pressing the accelerator to near maximum so they don't press it any further, thus believing the car will not accelerate, when actually it would if they would have pressed the pedal farther.

Realistically it's difficult to gauge how far you are pressing the pedal, other than when the pedal is to the floor, most of us gauge accelerator pedal position by engine sounds or acceleration. So the theory again is that when people experience super excessive high RPMs, the pedal is only slightly pressed, enough to only barely maintain speed, but the high engine revs causes the driver to think they are pressing the pedal more than they really are, thus creating a sensation that the car will not accelerate.

Again not saying this was your situation, but do you remember if you tried pressing the pedal all the way to the floor? Any chance you glanced at the power gauge during this time? I understand if you didn't as an incident like this can be quite distracting, but it would be helpful if it happens again to watch the power gauge to see what it indicates during the high rev situation. In preparation you may want to watch the power gauge in normal driving perhaps more than you normally do and memorize what levels the power gauge indicates at different accelerations. Then if the incident happens again you will have something to compare it to.

As for an RPM gauge, there are relatively inexpensive OBD2 bluetooth devices that you use with a phone app. Torque Pro is a popular app, the free version will show RPM. Again it would be good to use it in regular driving and note typical RPM's, then if the incident happens again you will have something to compare to. This won't necessarily help solve it but it will give you more of a qualitative description to report to the dealer.

@2002, Purchased the 2019 Honda Clarity in March of 2020 brand new. When it happened on 8/26, I noticed the sound first, then looked at the speedometer and saw the loss of speed from 39 miles per hour and continued to drop. I pushed the pedal a few times, and speed continue to drop. The second time was from a dead stop, I was able to get up to 19 miles an hour, and the car would not go past that. In both cases, what seemed to resolve the inability to accelerate was turn off HV mode for a moment (less than a minute), and re-enabling it again.

I'm waiting on the BlueDriving OBD-II; hopefully I can log other data should the event happen again.

@60Hertz, thank you for the link; it helps to understand this a lot better.

with our 2018 Clarity Touring a number of times the first year we owned it. Sometimes it would happen in the winter during severe cold, other times in the mountains with a fully loaded car. Very disturbing and also terribly dangerous, so I filed a formal complaint with the National Traffic Safety Board. In reference to an earlier post, pushing the accelerator pedal to the floor does no good in those situations. I took it to our local Honda dealer and they exerted a good faith effort by hooking up a computer and driving with me but we couldn't duplicate the problem -- no surprise there. I considered using our state's Lemon Law due to safety concerns, but we haven't had any problems the last 1.5 years so decided to keep it. Am heading to the mountains again in a couple weeks so will be interested to see if we encounter the same problems again. I know of no solution, other than keeping your battery as fully charged as possible whenever in HV mode.

@lefty, It seems like the problem I'm having now. It happens when it happens, and it happened again yesterday, I took the car into the shop today, and Honda could not find anything in the codes.

Thanks for the detailed info. I read all of the NHTSA reports a while back and I found eighteen that described a similar complaint, car would not accelerate, slowed down to 20 mph, etc. But most of them were from a couple of years ago there were very few recent reports. When I read the reports it sounded like what you experienced, in my opinion they couldn't all be explained by the high RPM theory where drivers are misled by alarmingly high RPM's into believing the car would not accelerate. Unfortunately none of the reports that I read specifically stated that they tried pressing the pedal to the floor, so there was no way to prove this wasn't the case to those who were dismissing the reports as just new owners who didn't understand how the car works. Although perhaps coincidentally I did notice that most of the reports were from people who had only owned the car for a relatively short time. It makes me wonder if perhaps the problem was a software glitch that somehow clears up as the car is driven longer and builds up more data. Or maybe the problem was fixed in a software patch that the owner may not have been aware occurred. Just guesses as a way to explain why the problem seems to have mostly gone away.

@2002, I am wondering the same thing; it seems like if this were a hardware problem there would be "codes" (smoke, sounds, etc.) but for Software I would expect an exception code for scenarios that did not meet the various use cases, unless it is an "undocumented feature" that perhaps Honda may not be aware.

Here are the details fo the occurrence on 2020/09/07 approx 3 PM.

(1) State of the car:
The car was in HV mode with 45% of battery

(2) Symptoms:
Pressed the gas and the engine revved and did not get past 12 miles per hour.

(3) Occurrence:
Driving Southbound on the 15 freeway downhill in Stop and Go traffic. I noticed the pressing the accelerator the would engine rev, and the car seemed to have trouble accelerating; this time, I unable to drive past 12 miles an hour.

Note: The 12 miles per hour is strange because I would not expect this to occur, considering the driving direction is downhill.

(4) Workarounds/What next?
What seemed to resolve the inability to accelerate was to disable HV mode, drive using electric for a bit, then turn HV Mode back on.

Took the car into the shop today, and Honda reported that there were no error codes that would indicate there was a problem and that Honda was unable to replicate the issue.

I've got a Blue OBD arriving, so I can start logging other engine parameters when this occurs. I'll share what I find the next time this happens.

 

[2002]

Here are the details fo the occurrence on 2020/09/07 approx 3 PM.

(1) State of the car:
The car was in HV mode with 45% of battery

(2) Symptoms:
Pressed the gas and the engine revved and did not get past 12 miles per hour.

(3) Occurrence:
Driving Southbound on the 15 freeway downhill in Stop and Go traffic. I noticed the pressing the accelerator the would engine rev, and the car seemed to have trouble accelerating; this time, I unable to drive past 12 miles an hour.

Note: The 12 miles per hour is strange because I would not expect this to occur, considering the driving direction is downhill.

So it happened to you again yesterday. While it was happening did you have a chance to glance at the power meter to see how the meter was reacting to accelerator pedal movement compared to other times? Did you try pressing the pedal to the floor? Also I realize you don't have an RPM gauge hooked up, but when the engine was revving was it louder than normal, or was it at a sound level that you hear in normal driving.

 

[knakkeow]

So it happened to you again yesterday. While it was happening did you have a chance to glance at the power meter to see how the meter was reacting to accelerator pedal movement compared to other times? Did you try pressing the pedal to the floor? Also I realize you don't have an RPM gauge hooked up, but when the engine was revving was it louder than normal, or was it at a sound level that you hear in normal driving.

Hi 2002,

Thank you for the quick follow-up.

I heard the sound first, looked at the dash and noticed that when pressing the accelerator down I would hear the engine rev and keeping an eye on the speedometer, I noticed it did not go past 12 miles an hour wiht the pedal down. I'm not sure why, what seems to fix the issue is to disable HV mode and re-enable it after a short period of time. I do not know how long this workaround will be effective though. :crying:

To equate the noise level to a manual transmission, it sounded like being in 1st gear, and forgetting to shift into 2nd gear when you enter the main street and flooring it.

I can't wait for the BlueDriver OBD-II to arrive so I can start logging the RPMs, Torque, Engine Loading, and Temps.

 

[2002]

Hi 2002,

Thank you for the quick follow-up.

I heard the sound first, looked at the dash and noticed that when pressing the accelerator down I would hear the engine rev and keeping an eye on the speedometer, I noticed it did not go past 12 miles an hour wiht the pedal down. I'm not sure why, what seems to fix the issue is to disable HV mode and re-enable it after a short period of time. I do not know how long this workaround will be effective though. :crying:

To equate the noise level to a manual transmission, it sounded like being in 1st gear, and forgetting to shift into 2nd gear when you enter the main street and flooring it.

I can't wait for the BlueDriver OBD-II to arrive so I can start logging the RPMs, Torque, Engine Loading, and Temps.

I am looking at it from the point of view of a Honda technician, they can't duplicate the problem on a test drive since it is random, and they don't see any codes, so they are relying completely on you for information. Even if you gave them a readout of RPM, torque and engine load, that doesn't really help because most of the time the Clarity engine is just spinning a generator and making electricity, some of which goes to the wheels and some of which goes to the battery. So RPM etc, or even the sounds that the engine is making, does not indicate how much power is actually being delivered to the wheels by the electric motor even in normal driving. Phone apps are not going to provide that level of information.

So the only clues that you can give them are what were the power levels indicated on the display, and what was the pedal position, as accurately as you can describe them. I have brought up the power gauge but I don't know if you know what I am talking about as you haven't mentioned it. There is a semi-circle that goes around the speedometer. Most critical to this discussion, the pointer starts out positioned at the left side of the circle when no power is going to the wheels. In normal driving as you press the accelerator the pointer begins to move around the circle. I mentioned before that you should observe how this pointer moves during normal driving, and how it relates to both pedal position and acceleration. I would pay specific attention to how far the pointer moves at various accelerations and at various cruising speeds in normal driving. It does not have numerical markings, but it does have eight "notches" around the circle. As you observe the pointer in routine driving you will see that the pointer is pretty consistent as to how many notches it moves at various accelerations and cruising speeds. I really think you should make these observations during normal driving, and then if the problem occurs again, I realize it's natural to focus on the speedometer, and I realize in traffic there is a stress to quickly solve the problem, but if there is any way possible while you are looking at the speedometer to also look at the pointer on the power circle and see where it is positioned and how it responds to accelerator pedal movement. This is the only gauge that shows power going to the wheels and thus in a loss of power situation it is an important gauge to look at.

A Honda technician will also want to know how far you are pressing the pedal. The problem is that this is completely subjective to describe, it is very difficult to communicate how far you are pressing the pedal. With one exception, pressing the pedal to the floor is about as unambiguous as you can get, i.e. you are pressing the pedal until it will not physically go any farther. I asked you if you tried pressing it to the floor, you said you pressed it down, but I don't know what that means, and neither would a Honda technician. Again I have no reason to question anything you are saying, I am just pointing out that from a technicians point of view, they need specifics, the more you can provide the better.

Actually the Clarity is unique because it has another unambiguous point in pedal travel which is the detent. I am not sure if you know what this is as I have not heard you mention it. The detent is a click that you can feel in the pedal when you are pressing the pedal nearly to the floor but not quite. It is designed mainly for driving in Eco mode where the detent is the point where the engine will come on in EV mode. In Normal and Sport modes the accelerator pedal is mapped differently so the detent does not really mean anything in those modes. But the important thing for your situation is that the detent provides another unambiguous indication of how far you are pressing the pedal which you can communicate to the technician. I recommend that in normal driving that you press the pedal to the detent to get used to how it feels when you go past it, and then if the incident occurs again as you press the pedal you will be able to recognize if you are going past the detent.

Ideally you could then tell the Honda technician something like this, "I pressed the accelerator pedal but the car would not accelerate. I could feel that I had pressed past the detent, and I continued to press the pedal all the way to the floor until it would not go any further. With the pedal to the floor the power indicator on the display did not even go to the first notch, and the speed would not go above 15 mph even though I was on level ground". This type of specific information will be invaluable to anyone trying to understand and troubleshoot the problem, as it removes subjectivity and ambiguity.

You may even want to consider mounting a video camera pointed at the display. Obviously that will result in mostly unusable footage that has to be discarded, but ideally the camera will be running (with sound) if the incident occurs again. It will show the power gauge, and the audio should pick up the engine sounds since you say it is very loud. And during the incident you should also give verbal commentary about where the pedal is positioned, i.e. "I am increasing pedal pressure. I just felt the detent and I have gone past it. I now have the pedal pressed completely to the floor". If you had a video like this that you could show to a technician it would go a long way towards getting them to escalate it to Honda technical.

 

[knakkeow]

@2002, Thank you for the in-depth explanation. I'll make sure to include those observations for the next time it happens. It is helpful and useful information.

Thank you!

 

[2002]

@2002, Thank you for the in-depth explanation. I'll make sure to include those observations for the next time it happens. It is helpful and useful information.

Thank you!

This rare problem is one that we have very few first hand reports, so I didn't want to miss this opportunity which is why I had so many specific questions, so thank you for providing the details that you have already.

 

[lefty]

Unfortunately, after 1.5 years, we experienced this problem again...

while in the mountains of Colorado last week. From previous experience we knew when climbing mountains we needed to be sure to have plenty of battery 'back-up', and our first few days of climbing over high passes in HV mode went OK...it was a struggle for the ICE, but it got the job done. Then one day we stopped at a Post Office and forgot to put it into HV mode when we restarted it before climbing. The battery miles got all used up just as we began to climb, and suddenly we lost most of our power, with speed dropping to 20, and eventually down to 7 mph. We stopped multiple times, turned off the car, and tried to start again, but you can imagine the danger in climbing a steep mountain road with cars zipping by at 60 mph and us trying to drive on the side of the road at 7 mph. It was a loooong and stressful climb up to the pass, as you can imagine. And dangerous. We were able to get the battery charged up a bit on the downhill coast, then I was able to find a charger station before we returned over the same pass later that day. No problems the rest of the trip. It's such a helpless feeling when this happens: you can be going, and then suddenly the engine revs up to high RPMs and the 'power indicator' on the dash simultaneously drops to 0. On one hand, this was our fault, as we know how to prevent it. On the other hand, Honda really needs a fix for this.

 

[2002]

It seems like it has to be a software issue, which makes it even more perplexing that Honda hasn't solved it. The reason I think it's a software issue is because even with an empty battery the engine can provide approximate 100 horsepower via the generator, which although that's very weak for a 4,000 lb car it should still at least be functional. Also I have never heard of someone in this situation having no power, i.e the car comes to a stop and will not move, instead all of the reports that I have ever read including yours the speed drops below 20 for example, or 7 in your case going uphill, but there is still power. Just to confirm, on the power display your needle was exactly at the 270 degree mark? In normal driving when the needle is above that mark there is power, below that mark it is doing regen, and exactly on the mark you are coasting. In normal driving if you take your foot off the pedal the needle will drop below center because of regen, until you get below about 5 mph then regen stops and the needle goes to center just prior to coming to a final stop. Also while coming to a stop sometimes I want to coast farther so I press the accelerator pedal slightly to stop the regen, if I hold the needle at center then it is coasting almost like being in neutral. Anyway do you remember if the needle was exactly at 270 or was it maybe slightly above?

Either way it sounds like when this problem occurs the car has gone into some type of limp mode, which a lot of cars do when there is a major problem that can lead to damage to the powertrain, but they give you enough power to at least move off the road and get to safety. My theory is that a software glitch causes the system to mistakenly think there is a problem that requires limp mode. But unfortunately this software glitch doesn't seem to leave any codes in the computer for a technician to view later, which is also why people with the problem don't seem to get any warning messages on the display. Also turning the car off and on again usually fixes it so that seems to prove that there is no actual problem with the powertrain. Although your latest experience is less common where turning the car off and on again didn't solve it, even temporarily.

One thing you might try if it happens again is switching to HV Charge mode. I say this only because people have reported that HV Charge works differently than normal HV, it's more than just the expected extra RPM's to charge the battery, but other slightly different behaviors, to the point that some people drive in HV Charge all the time instead of HV. There is a slight possibility that the software glitch does not occur in HV Charge, not by design, but assuming the software glitch is a typical software bug where an oversight in the programming causes problems in certain exact scenarios, maybe by some luck that buggy piece of code is not in the HV Charge routine.

Also if you ever accidentally let the EV miles get to 0 (which is easy to do) you can use HV Charge to get just over 50% charge on the battery. Of course ideally you would realize that you are in this situation when you are still far enough away from the mountain that HV Charge has enough time to recharge the battery.

 

[2002]

One more thing, have you ever done a 12V reboot on your Clarity? That's where you disconnect the negative terminal on the 12V battery for a minute or so then reconnect it. This essentially reboots the system and has cured many an odd software problem. After doing the reboot, the next time you start the car you will get several alarming messages about VSC and TPMS etc. but that is normal and those message go away after about a mile of driving. The 12V reboot also occurs if you replace the 12V battery since of course it has to be disconnected, or if you accidently let the 12V battery discharge requiring a jump start. So if you have had either of those happen since you have owned the car then you have already done the 12V reboot, but if neither of those has happened since you have owned your Clarity then you may want to do it proactively sometime before your next venture into the mountains.

 

[lefty]

Thanks for the ideas.

The power supply needle was exactly at the 270 mark when the problem was happening. The RPMs dramatically go up and the power needle drops dramatically at the same time. It feels as if nearly all power to the wheels are suddenly being cut off -- as if power is suddenly being rerouted elsewhere.

Trying HV Charge mode is a good idea -- the reason I didn't think to do that is because earlier on the trip when battery charge was on 0, and we were traveling along fine on a moderate incline I put it in HV Charge mode. Surprisingly, it wouldn't charge the battery at all, even after traveling a significant distance; surprising, because typically on flat roads it's always charged the battery in HV Charge mode.

I've never rebooted the 12v battery. May give that a try. Thanks again for the tip. That's more than Honda has provided.

 

[knakkeow]

Hi everyone, thank you for your input and feedback.

I wanted to provide an update about the issues.

I've been recording my drives using the OBD-II BlueDriver in hopes of capturing the event, and maybe I'm speaking too soon. I have not experienced the problem since my post in 2020/09, knock on wood.
@2002, it seems like your assessment may be correct. I notice when the car is under 25 mph, sometimes the RPMs go as high as 4000 (viewing the data from the OBD) and seem to drop after passing 30 mph, presumably because of changing "gears". Other times, based on the available battery charge, the car prefers the electric engine up to a certain point.

If i capture the event using the OBD, I'll post the data I've collected.

 

[lefty]

Please do post

your results -- I for one will be very interested!

 

[knakkeow]

HAPPY MONDAY!

Update, today approx 1:00 pm, when I started my car, I observed the following alarm messages:

• Power System Problem. Stop Driving When Safe
• Electric Parking Brake Problem
• Tire pressure monitor problem
• Plug-in Charging System Problem. Range Limited
• Brake System Problem
• Brake Hold System Problem
• Power Steering System (EPS) Problem
• Vehicle Stability Assist (VSA) Problem
• Hill Start Assist Problem
• Road Departure Mitigation System Problem

And the fan very loud and audible. :crying:

Luckily it happened in the middle of the day, so I had it towed to the Honda Service Center near my residence.

This is the 3rd time I've had the car in at the dealership for power loss problems.

Luckily, I could record it from a safe place, and when the AAA Driver asked what's up, I was able to show him.

 

[ClarityDave]

My guess is you have a 12v battery problem.

 

[KC_Kru]

Hi everyone,

I had an issue on August 23, 2020, where the car slowed down and over-revved twice. Today, I took the car to the dealer this morning, and was told (1) Honda's Diagnostic tools could not find indications that an error or an issue occurred, (2) could not replicate the problem, and (3) without a diagnostic capture of the incident the dealership could do nothing about it.

After some research today, it seemed like others may be having similar issues. How were you able to (1) resolve the issue with Honda and (2) able to help document the Computer error code so the next time it happened?

Would anyone recommend an OBD tool that can monitor in real-time what "gear" the CVT is in, engine loading, speed, temp, and other parameters that may help isolate the problem while driving?

Here is what happened below:

(1) State of the car:
Car was in HV mode with 75% of battery, and not going uphill.

(2) Symptoms:
While driving or starting from a stop, the engine sounded like it shifted into a lower gear by the loud engine revving noises it made. It occurred twice.

(2a) Occurrence 1:
While driving at 35 miles an hour, the transmission sounded like it went to a lower gear, and the car was slowing down even after pressing on the gas. What seemed to address the problem was turning off HV mode, let it go into EV mode, then put it back into HV Mode.

(2b) Occurrence 2:
Between 10 to 20 minutes later. From a full stop at a stoplight, the transmission sounded like it was stuck in a lower gear, pressing the gas did not accelerate the car past 19 miles/hour. What seemed to address the problem was turning off HV mode, let it go into EV mode, then put it back into HV Mode.

In both cases, putting the car back into EV Mode, then back in HV mode, seemed to resolve the problem of the loss of power and engine over-rev. It seems odd to me that Honda would not have a fix for this yet.

Any luck with fixing your issue? I have run into same issue multiple times and dealer is taking detailed look but they can't find anything.