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Hi. I have a 2019 Clarity Touring PHEV mfg date 10/19 and notice when the EV battery runs out and switches to ICE the engine revs very high and loud.

Steps to reproduce:
1. driving mode EV mode with ECON ON
2. start driving with some EV range left e.g. 5 miles
3. continue driving, when EV range goes to 0 and ICE starts, issue occurs: engine high revs very high and loud
Workaround: pull over and stop / start the car seems to lower the high rev ICE

Already had A1 service and currently at 12,800 mileage

Thanks
 

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Previous threads may help



Under the conditions you describe...engine rev is normal. Folks get alarmed because the motor is loud relative to speed and this car doesn't "sound" like a normal car...agreed...but for most conditions it is normal.

Threads should help. Good luck.
 

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Hi. I have a 2019 Clarity Touring PHEV mfg date 10/19 and notice when the EV battery runs out and switches to ICE the engine revs very high and loud.

Steps to reproduce:
1. driving mode EV mode with ECON ON
2. start driving with some EV range left e.g. 5 miles
3. continue driving, when EV range goes to 0 and ICE starts, issue occurs: engine high revs very high and loud
Workaround: pull over and stop / start the car seems to lower the high rev ICE

Already had A1 service and currently at 12,800 mileage

Thanks
Just my take on it. The engine is revving high because it is trying to get some charge into the battery as well as supply the motor with energy since the car is being driven. When you pull the car over and stop/start, it is only charging the battery since you’re no longer driving the car. I assume the revving eventually slows down or at least gets less noisy as the battery gets enough charge and the load on the engine lessens. I have heard some people refer to the revving engine as “angry bees”.
 

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My interpretation of the high revs is that as the battery becomes depleted, the engine starts but in a warm up period. It may actually be using that 10% reserve of battery power. After the warm up, the engine uses high revs to get the battery back to the base level. A similar situation occurs when you switch to an HV mode with a cold engine.
 

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2021 PHEV Touring HB, CA
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My interpretation of the high revs is that as the battery becomes depleted, the engine starts but in a warm up period. It may actually be using that 10% reserve of battery power. After the warm up, the engine uses high revs to get the battery back to the base level. A similar situation occurs when you switch to an HV mode with a cold engine.
I've noticed that behavior upon switching to HV at 50% SOC on a cold engine. Mine will often lose a segment (or two) on the SOC, and then hold the SOC there, after a couple minutes.

Yours seems like a reasonable hypothesis to explain high revs at low SOC.

The engineer in me is whispering..."now, how to test it..."
 

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2018 PHEV Touring Atlanta, GA
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I've noticed that behavior upon switching to HV at 50% SOC on a cold engine. Mine will often lose a segment (or two) on the SOC, and then hold the SOC there, after a couple minutes.

Yours seems like a reasonable hypothesis to explain high revs at low SOC.

The engineer in me is whispering..."now, how to test it..."
I have observed that it reaches 0 miles at about 10%, and then goes down to about 8% while warming up, maybe as low as 7% sometimes, then it charges up to around 12%, then pretty much fluctuates between 8% and 12%. Some of that is from monitoring the OBD-II adapter, but actually most of it is simply from arriving home with 0 miles, then later when I use HondaLink to schedule my nightly charge I notice the SOC and it's usually in that range.

An interesting quirk you may have noticed, if you turn off the car with less than about 2.5 EV miles remaining, the next time you start the car it will show 0 EV miles. What happened, did someone siphon off some of your electricity while you were aware from your car? No, it's just that while seems to use 10% as the cutoff while driving, when starting the car it seems to require at least 15% SOC, anything less than that it starts out with 0 miles. My guess is that it figures that if you are that low on SOC starting out you are going to be in HV mode very soon anyway, so it just goes ahead and starts in HV.
 

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How fast are you going when this happens. At moderate speeds (55-65 MPH) on flat ground the extra engine rev isn't that long while the car recharges the battery to the 0% SOC point. It went below this point while the ICE was warming up and needs to recharge the battery some.
 
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If the EV miles wind down to zero while driving in a high power demand, the gas engine comes on and warms up at idle for a couple of minutes. In the meanwhile the current power demand is still being largely met the the battery which is dipping into the bottom end reserve. Once the gas engine warms up, it has to play catch up supplying the current driving power demand plus restoring the battery reserve margin. It can be a stark contrast going from the almost silent running EV to having the little engine that could working its heart out. It can also an odd sensation for most who have spent a lifetime driving and riding in conventional gas engine vehicles where the engine sounds are always in lock step with the amount of power going to the drive wheels.

There's no harm in letting the car do it's thing. After a few minutes the engine will catch up and the RPMs will come down. As a matter of personal preference, I manage this more proactively. If I know I am going beyond battery only range, then I'll manually select HV mode while I still have at least 5 miles of EV range left and preferably while I'm in a lower power demand driving situation. For example, while in surface street driving before getting the highway. Then when I get off the highway and approach my destination where I can charge, I go back to EV mode on the remaining battery power.
 

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Hi. I have a 2019 Clarity Touring PHEV mfg date 10/19 and notice when the EV battery runs out and switches to ICE the engine revs very high and loud.

Steps to reproduce:
1. driving mode EV mode with ECON ON
2. start driving with some EV range left e.g. 5 miles
3. continue driving, when EV range goes to 0 and ICE starts, issue occurs: engine high revs very high and loud
Workaround: pull over and stop / start the car seems to lower the high rev ICE

Already had A1 service and currently at 12,800 mileage

Thanks
That is normal. I usually switch to Sport
Hi. I have a 2019 Clarity Touring PHEV mfg date 10/19 and notice when the EV battery runs out and switches to ICE the engine revs very high and loud.

Steps to reproduce:
1. driving mode EV mode with ECON ON
2. start driving with some EV range left e.g. 5 miles
3. continue driving, when EV range goes to 0 and ICE starts, issue occurs: engine high revs very high and loud
Workaround: pull over and stop / start the car seems to lower the high rev ICE

Already had A1 service and currently at 12,800 mileage

Thanks
That is normal in my experience. My wife hates it. I usually switch to Sport Mode. It makes the car very peppy and seems to reduce the revs which I attribute to EV Mode.
 

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The complication with discussions on this topic is that we really don't know exactly how loud and how high of RPM's are actually being experienced by the person reporting the problem. We all interpret the OP's statement, "when the EV battery runs out and switches to ICE the engine revs very high and loud" based on our own experience with our cars, we assume that the person reporting the problem is hearing the same thing that we do but is simply not used to how hybrids work. While that may be true most of the time, there have been people over the years who have reported abnormally high RPM in their Clarity, something that most of us haven't experienced, at least I haven't. Terms like redlining have been used to describe it, alarming is another word used. We don't hear of this extreme situation very often anymore, one theory is that it gets cleared by 12V reset, which some owners may have done for other reasons.

However for any particular situation being reported it's hard to know what is going on unless we get more specific details from the person reporting the problem. In this case the OP stated, "the engine revs very high and loud", but we really don't know what that means. It could be just the somewhat annoying higher RPM that we all experience at times when EV miles are 0, or it could be one of the more rare redlining situations that people in the past have reported. No way to know unless we hear for ourselves what sound their car is making, but that's not really feasible. Even if they posted an audio recording we probably wouldn't be able to determine much. What would help is if someone who is experiencing the problem used an OBD-II device so they could report the actual RPM's, but probably few people are going to do that.

My guess also is that the OP is experiencing normal behavior, but we really don't know for sure.
 

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"We don't hear of this extreme situation very often anymore, one theory is that it gets cleared by 12V reset, which some owners may have done for other reasons."

I do think the theory is true, for some reason the computer that controls the battery charge level can get into a corrupt state. I have experienced this resent after a long trip on ICE only, well over 1000 miles.

During startup in the am the ICE is running at much higher rpm than I have ever heard. I "assume" the battery perhaps was drained too low due to errors and the compensate is higher rpm when the ICE/generator kicks in.

Tomorrow I will disconnect the battery to reset the system and monitor the am starting rpm over a weeks' time.
 

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I use a scan gauge II to watch the rpm and engine temp, engine load.

Before reaching zero. Press the pedal to the floor briefly to trick the ICE to turn on. It will come on at 1500rpm around a 30% load while it warms up to 160 degrees before shutting off.

By the time it reaches warm up you could be near zero EV or better is to select HV with a few miles remaining on EV. Use that last few miles right before reaching final destination.
 
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