My reliable 2018 Touring (75K miles) has slowly lost battery range over the years(~30-35 or so now), as expected. About a month ago, the check engine light came on, so I hooked up my ODB II dongle to see what was going on. It told me there was a P1DC7 and P0A7F fault related to hybrid battery deterioration. I took it into Honda and they verified the fault, but told me that Honda needed to see the fault again after they reset the code before they would replace the battery pack. (sounds like it would take a year to get one, but that's a story for another day...) Anyway, they kept the car for a full day before returning it to me, but here's what's odd: the guessometer range has dramatically increased. Where I used to se on average a 35 mile range at 100%, I now see over 50miles consistently. I figured they just erased some memory with a "factory reset" or something, but the range after a month and ~1.5K miles remains in the high 40's. The fault codes have not reappeared. What the heck could have happened? Does the clarity have some kind of secret reserve capacity the tech enabled? Is the guessometer gaslighting me? Any thoughts?
Increased battery range after service for check engine light
- Thread starter PriusGeek
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ClarityDoc
Well-Known Member
More relevant than the guess-o-meter estimate would be your actual experience with range. Has the EV range increased? If I had to hazard a guess, I would guess that it has not.
MrFixit
Well-Known Member
The Clarity constantly monitors the HV battery capacity. It uses some sort of algorithm that we can only make guesses about. There are certain actions (likely taken by your dealer) that can 'reset' the capacity measurement back to a factory fresh state (55 Ah). BUT - this does nothing to actually improve the battery capacity. It simply re-starts the measurement algorithm. Your car will (unfortunately very gradually) re-calculate the actual capacity, and it will return back to your former 'normal' condition. In the meantime, your range estimates will give you a false sense of 'improvement'. This process can take many weeks depending on your driving / charging routines.
You can read more about battery capacity in this thread HERE
You can read more about battery capacity in this thread HERE
As a point of information on the battery capacity reset, it just reset on my 2018 Clarity. This happened after I did, at the Hondalink Tech person's instruction, a full data reset for the central display/system. My Clarity could not get SOC, odometer, and location data after the HondaLink update a few weeks ago. I also did a reboot of the Android system on the central display. I had disconnected the 12V battery a couple of weeks previously to replace the 12 V battery with no reset.
I checked the battery capacity after the data reset and was at 54.9 AH after being at 49.86 in Novmber, 2024. I will wait for few charge cycles before checking again. I have found that I need to have the SOC at less than 30% and then do a full charge to 100% to get a new battery capacity reading (similar to what is needed to get the battery capacity for a laptop or a cell phone).
LeoP
I checked the battery capacity after the data reset and was at 54.9 AH after being at 49.86 in Novmber, 2024. I will wait for few charge cycles before checking again. I have found that I need to have the SOC at less than 30% and then do a full charge to 100% to get a new battery capacity reading (similar to what is needed to get the battery capacity for a laptop or a cell phone).
LeoP
NorCalPete
Well-Known Member
@leop, thank you for this information. Unless I missed it, I don't believe that the actual cause of a battery capacity reset has ever been determined or reported on this forum. I'd rather not trigger a capacity reset if I can avoid it, so now I know what not to do when I'm tinkering with the car just for the fun of it. I realize no damage is caused, but I'd rather not have to wait weeks or months for the capacity to recalibrate back to an accurate reading.
The only downside to a reset is that there will be inaccurate readings for a period of time. One solution would be to just not monitor it for a few months. Alternatively, it could be a fascinating study to track its return to the previous level. Others may prefer to watch paint dry.
Thank you! This explains what I'm seeing. Haven't put many miles on it since the "reset", but have an upcoming road trip that should get things back to normal.
Hobbesgsr
Well-Known Member
This is exactly what happened to me this week! 42Ah to 55Ah...codes wiped by dealer.
Cruising to the metroplex Monday in sport and HV modes as is customary. About 20 min's into the hour trip, CEL illuminated. I fired up the Car Scanner app and checked codes: P1DC7, P0A7F, and P0EDD.
Conditions on Start-up: Cold morning, maybe 30 deg F. HV batt capacity per CarScanner was 38.96 and guessed EV range was 31.5.
Conditions at the advent of codes were 75 mph w/cc engaged. SOC = 89% and guessed EV range was 24.5.
I thought better of clearing them on-the-go, as it were, and deferred that action until I could exit the Express Lanes and achieve a quiet parking lot.
In the intervening 30 minutes or so, still cruising at 75-80 mph, I noticed a dimly lit "Power System" caution. It was a very bright morning, lots of glare on the instrument panel, so it may have illuminated coincident to the CEL, but I only noticed it a bit later. It is much dimmer than the CEL and other instrumentation. Additionally, the car was out of Sport mode and could not be switched back into sport nor even Eco, illuminating a message saying "Driving mode cannot be changed"
After I was able to park, leaving car on, I attempted a code-clear. No dice. CarScanner suggesting some vehicles may require Engine Off and key in "On" or "accessory" position. After executing it in that fashion, CEL and Power System cautions were extinguished. However, re-reading DTC codes yielded: "P1DC7 Archive (inactive), P0A7F Archive (inactive) and P0EDD Archive (inactive)"
I proceeded on to my destination via residential and urban streets in HV and Sport mode, which was now also available. A few minutes in, I noticed the guessed EV range was now at 35.8 miles, so I took a gander at HV capacity and SOC: 54.98 ah and 89% SOC.
I charge almost exclusively on Lvl 2 with 16 a. Occasionally (rarely) with the lvl 1 charger and just as rarely with the Lvl 2 cranked up to 32 a.
Full charge now sporting 41.5 mi, vs. 29-32 prior, depending on ambient temp. I've only driven it once since then: Sport mode, no HV to town and back. That is an actual 10 miles round trip and it consumed 15 miles of EV guessing range. However, that is pretty standard for that trip. The trip is almost exclusively 75 mph freeway, where the guessing miles have never lasted a whole mile. At least 8 of 10 miles are hi-speed freeway with one stoplight that ALWAYS stops me on the return trip. (Going in, it's a right hand turn, to a 45 mph street, so more rolling turn than stop most times and much less acceleration energy required vs. the return, full stop followed by acceleration to 70+mph)
We'll see how it tracks from here.....
Edit: Car is a 2019 Touring with 175k miles
Conditions on Start-up: Cold morning, maybe 30 deg F. HV batt capacity per CarScanner was 38.96 and guessed EV range was 31.5.
Conditions at the advent of codes were 75 mph w/cc engaged. SOC = 89% and guessed EV range was 24.5.
I thought better of clearing them on-the-go, as it were, and deferred that action until I could exit the Express Lanes and achieve a quiet parking lot.
In the intervening 30 minutes or so, still cruising at 75-80 mph, I noticed a dimly lit "Power System" caution. It was a very bright morning, lots of glare on the instrument panel, so it may have illuminated coincident to the CEL, but I only noticed it a bit later. It is much dimmer than the CEL and other instrumentation. Additionally, the car was out of Sport mode and could not be switched back into sport nor even Eco, illuminating a message saying "Driving mode cannot be changed"
After I was able to park, leaving car on, I attempted a code-clear. No dice. CarScanner suggesting some vehicles may require Engine Off and key in "On" or "accessory" position. After executing it in that fashion, CEL and Power System cautions were extinguished. However, re-reading DTC codes yielded: "P1DC7 Archive (inactive), P0A7F Archive (inactive) and P0EDD Archive (inactive)"
I proceeded on to my destination via residential and urban streets in HV and Sport mode, which was now also available. A few minutes in, I noticed the guessed EV range was now at 35.8 miles, so I took a gander at HV capacity and SOC: 54.98 ah and 89% SOC.
I charge almost exclusively on Lvl 2 with 16 a. Occasionally (rarely) with the lvl 1 charger and just as rarely with the Lvl 2 cranked up to 32 a.
Full charge now sporting 41.5 mi, vs. 29-32 prior, depending on ambient temp. I've only driven it once since then: Sport mode, no HV to town and back. That is an actual 10 miles round trip and it consumed 15 miles of EV guessing range. However, that is pretty standard for that trip. The trip is almost exclusively 75 mph freeway, where the guessing miles have never lasted a whole mile. At least 8 of 10 miles are hi-speed freeway with one stoplight that ALWAYS stops me on the return trip. (Going in, it's a right hand turn, to a 45 mph street, so more rolling turn than stop most times and much less acceleration energy required vs. the return, full stop followed by acceleration to 70+mph)
We'll see how it tracks from here.....
Edit: Car is a 2019 Touring with 175k miles
When you need to clear codes, you can NOT do it with the ignition in the R2D mode (Ready to drive). It needs to be in AUX mode.
When you clear the codes, they stay on as "History" or "Permanent codes" until you run enough cycles with the car on and off and all the sensors are active and in ready mode. It will recheck those codes and if nothing appears wrong, it clears them from the ECU.
When you flash or clear the codes, sometimes it will reset your Battery capacity as well as reset your GOM tracker. Nothing out of the ordinary.
Those codes you got are more than likely your 12v battery dropping lower than recommended. These claritys are extremely picky with their electronics. Nothing crazy to worry about if it happens again just start to consider charging the 12v with a battery tender from time to time and/or replacing the battery if its more than maybe 3 years old.
As for charging L1 or L2, I personally don't think it matters. I charge at home daily with L1 and charge at work L2 every single day. Have people reported 1 is safer than the other?
When you clear the codes, they stay on as "History" or "Permanent codes" until you run enough cycles with the car on and off and all the sensors are active and in ready mode. It will recheck those codes and if nothing appears wrong, it clears them from the ECU.
When you flash or clear the codes, sometimes it will reset your Battery capacity as well as reset your GOM tracker. Nothing out of the ordinary.
Those codes you got are more than likely your 12v battery dropping lower than recommended. These claritys are extremely picky with their electronics. Nothing crazy to worry about if it happens again just start to consider charging the 12v with a battery tender from time to time and/or replacing the battery if its more than maybe 3 years old.
As for charging L1 or L2, I personally don't think it matters. I charge at home daily with L1 and charge at work L2 every single day. Have people reported 1 is safer than the other?
Doubtful on the 12V. Yes, I know they cause a host of what most would consider non-battery-related codes. In my Jaguars, a flat battery will normally trigger all sorts of transmission and other assorted control module codes - driver seat, window failure, oh, let's not forget the park brake failure!
My Clarity's 12V failed a couple months ago. Dead car, nothing....after a couple of weeks unmolested while I was traveling. Boosted it with a lithium jumper and all was well for a few weeks. Then I started not getting a "Ready to drive" after pushing the start button, but rather Aux mode. I first attributed it to a too-quick button push or perhaps lack of coordination between brake pedal and quick button push. But a few more instances and I decided best to knit round to the dealer and pick up a replacement battery.
So I'm not saying that it CAN'T be the case and that the 12V MUST be good because it is new....but the odds are not in favor of it. Particularly given that my HV battery was flirting with the warranty-replacement capacity of 35 ah. Not warranty, of-course as I'm at 175k mi.....
Edit: Just took it out for a few errands. 16 miles elapsed on the odometer, depleted EV GOM mileage from 40.5 to 23.3, or 17.2 miles. ODO doesn't show tenths, so beginning mileage may have been in the range 175046.0 - 175046.9 and ending perhaps 175062.0 - 175062.9.
Maths are hard, but I reckon that's between 15.1 and 16.9 miles actually driven vs. 17.2 miles evaporated from EV range. GIven the amount of highway mileage involved, that is pretty close to what I have observed since purchasing the car in 2022. In other words, it does not appear that the GOM is being greatly fooled as one might think with an immediate and magical gain of 16.02 ah in battery capacity. 65 deg F today, so that helps preserve the trons, vs. high 20's on the day the problem surfaced.
Performed another code read and all DTC's are gone.
My Clarity's 12V failed a couple months ago. Dead car, nothing....after a couple of weeks unmolested while I was traveling. Boosted it with a lithium jumper and all was well for a few weeks. Then I started not getting a "Ready to drive" after pushing the start button, but rather Aux mode. I first attributed it to a too-quick button push or perhaps lack of coordination between brake pedal and quick button push. But a few more instances and I decided best to knit round to the dealer and pick up a replacement battery.
So I'm not saying that it CAN'T be the case and that the 12V MUST be good because it is new....but the odds are not in favor of it. Particularly given that my HV battery was flirting with the warranty-replacement capacity of 35 ah. Not warranty, of-course as I'm at 175k mi.....
Edit: Just took it out for a few errands. 16 miles elapsed on the odometer, depleted EV GOM mileage from 40.5 to 23.3, or 17.2 miles. ODO doesn't show tenths, so beginning mileage may have been in the range 175046.0 - 175046.9 and ending perhaps 175062.0 - 175062.9.
Maths are hard, but I reckon that's between 15.1 and 16.9 miles actually driven vs. 17.2 miles evaporated from EV range. GIven the amount of highway mileage involved, that is pretty close to what I have observed since purchasing the car in 2022. In other words, it does not appear that the GOM is being greatly fooled as one might think with an immediate and magical gain of 16.02 ah in battery capacity. 65 deg F today, so that helps preserve the trons, vs. high 20's on the day the problem surfaced.
Performed another code read and all DTC's are gone.
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