DTC P26A3: Electric Water Valve Malfunction

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AnthonyW

AnthonyW

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This DTC has come up in a few other threads, but I wanted to create a separate thread dedicated since this has happened to a couple other drivers here and on Facebook. May become a common issue but let's hope not. Honda advance diagnostic for this code is attached.

The warning that comes up on the car is "Emissions System Problem".

I got this DTC a couple of times. Cleared it myself the first time. Came back this weekend. Took it into the dealership and they confirmed that the water valve is sticking. Like others it will take a week or so to get the part in. They said it is okay to drive as this would only be an issue when it is cold outside and the heater is trying to pull coolant from the ICE (if the ICE were on). Based on what I read, I tend to agree that it is okay to drive. Take a look at the attached service manual and let me know if you agree.
 

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Thanks for the heads up.

This Saturday we drove about 240 miles from Raleigh, NC to Shenandoah N.P. I started driving on HV with about half the EV range left but that was not enough to stop the bees from showing up as we went up some of the really big mountains as the EV range had dropped very low over the 3,500 ft elevation gain.

I was able to get a partial charge at one of the visitors centers but when I tried a short time later at another charger the charger faulted but the car showed no fault. Late that afternoon I was able to complete the charge.

Now for my question - when we went out for a drive about 9 PM I had the Emissions System Problem warning and it was still there Sunday morning. The charger that had worked before faulted out. Does the "ESP" warning also cause a condition that does not allow charging?

I finally bought an adjustable end wrench and disconnected the battery to clear the fault before our drive home and had no further warnings.

geo
 
This is one of the DTC's that can cause that warning but I am sure it is not the only one. I have a list of all the possible DTC's that the Clarity PHEV can throw but nothing that cross references the associated Infotainment warnings.
 
K8QM said:
Thanks for the heads up.

...
I finally bought an adjustable end wrench and disconnected the battery to clear the fault before our drive home and had no further warnings.

geo
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Sorry that you had problems during your pleasure trip to the mountains. I'm thinking it might be wise for me to carry a wrench in the car, just in case, but I think I remember a reference to a fuse that can be pulled and reseated to accomplish the same reset. If anyone knows if that is factual, and can share which fuse it is, it could be a valuable bit of knowledge to anyone coping with warnings while in transit.
 
Perhaps Honda would get the message if service technicians began finding these switches installed atop the battery of every Clarity they work on. Just kidding; Honda isn't in the message-getting business.

battery-disconnect-knife-switch.jpg


If anyone does install one of these very tall switches, please post a photo of what your aluminum hood looks like after you close it. Actually, there are much more sophisticated compact battery disconnect switches available. I just liked the basic look of this knife switch--something you'd expect to see in a Frankenstein movie.
 
I’ve seen a lower height cut off switch in the auto parts stores ans at Wally World that has a knob you insert and remove. I think it’s more for anti-theft or long term storage uses but would work easier and with less wear and tear in your connections. It’s less than $10 and there are more expensive ones as well.
6025BA9D-C350-4BAE-AE50-0B3D924AA982.webp
 
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Got the same problem during the weekend. Not really sure the issue is the same as the one described in the PDF, since the warning popped up while I was driving on the freeway (EV), way past 15 seconds from start.
Anyway, dealer this morning, P26A3 DTC found, they had a look at the valve, which looked ok, they cleared the DTC and contacted the Honda tech forum, which apparently told them it's a known issue with no acknowledged solution yet... They drove the car back to me, and the same warning popped up again, so I was told to wait and see, and contact them back in a couple of weeks if the warning was still there (I might do a battery-off reset myself next weekend and see what happens...)
After reading that with the same DTC other dealers replaced the valve, I think I'll insist on that if the DTC is still there in a few weeks.

Not that I'm worried, since I drive almost exclusively electric (first trip to the gas station 2 weeks ago, after 3000 miles in 4 months), but it's a bit unsettling...
 
I have not had the warning come back on since I got mine repaired so I think it is an actual hardware problem and not just a software glitch. As I understand it, it is not a mission critical part but it will cause you to lose efficiency once it starts to get cold outside. When there is a call for heat in the interior cabin, it regulates the coolant flow between the electric heater and the ICE, choosing which the one that is best prepared to answer the call. So in one example, if your ICE was running but the valve was stuck closed, the electric heater would have to heat the coolant. In this case it would most a whole lot more efficient to borrow coolant that has already been warmed by the ICE to do the job.
 
Putting the words Emission System Problem in this thread so that it comes up when people search.


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I got this code today. Going to the dealer tomorrow. Pretty odd for a 2.5-month old car with 3.5k miles, little ICE use and almost no heater use.
 
If it’s not a sensor failure or a one off computer glitch (darn those random cosmic rays), I’ll bet that replacing the faulty valve will return your Clarity to its perfect state.
 
Waiting at the service department now; my Clarity has 4 product updates they need to apply: the HV estimated mileage fix, EVTC failure misdetection (I think this is the P26A3 code), Emission Warranty CD update, and Abnormal Water Temperature Reading. I think the latter one requires a part; the others seem to be software-only.

While waiting, checked the HondaLink app and the HV mileage went from 880 miles to 245, so they are furiously working on it.
 
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Would you mind sharing the EVTC failure misdetection and Abnormal Water Temp reading service bulletin numbers, if you got them from the dealer? So in case it happens again I can tell them what to do (my dealer was really reluctant to apply any SB without me arguing for them...)
 
EVTC Failure Misdetection: SB 18-089
HV Range Display: SB 18-091 (seems different from the one others reported)
Abnormal water temperature reading: SB 18-090. For this one, they ordered a part and said it will take several hours and they would have to disassemble the entire dashboard.

In my case, the service advisor went to his computer, looked up my car by vin and said: you have 4 product updates available.
 
Thank! Yep, the services rep at the local dealership will apply an update only if I have a specific complain that is listed as solved by the update... so I'd better go prepared.
 
It appears that the fix for the DTC P26A3 is now a software update mentioned in Service Bulletin 18-089, dated 10/4/2018. I was told that this Service Bulletin supersedes Service Bulletin 18-079. Another Service Bulletin, 18-090, calls for the replacement of the Climate Control Unit. I suspect that this may also be related to problems with the heating water control since the issue corrected is described as coming up when running the heater. These two Service Bulletin updates are to be done at the same time along with a new software update, 18-091, to correct the HV mileage issue. All three (3) Service Bulletins are part of a recall campaign for the affected Clarity automobiles.
 
Makes sense. I have been waiting for the climate control unit to be replaced for 6 hours so far. Hope they will be done soon.
 
That’s very interesting. I got the Emissions System warning that was triggered by P26A3. They physically replaced electric water valve and I haven’t had the problem since. I am wondering how a software patch, can fix a hardware defect. Guess its time to go to the Bat Computer. It’s been about 4 months since I checked in...


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AnthonyW said:
That’s very interesting. I got the Emissions System warning that was triggered by P26A3. They physically replaced electric water valve and I haven’t had the problem since. I am wondering how a software patch, can fix a hardware defect. Guess its time to go to the Bat Computer. It’s been about 4 months since I checked in...
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@AnthonyW, unless you really are Bruce Wayne with all his money, I’d be happy to send you a little cash for your Honda Link searches. They’re been a great source of information for us.
 
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