Dudley Fuddpucker

Well, talk about massively disappointed! I am the proud owner of a 2020 RLX Sport Hybrid, purchased new in August 2020. The car has been a dream to own, and I never had a single regret, but yesterday may be giving me some doubt.

In a nutshell, I ran a short errand yesterday afternoon (was working from my home office) and on my way back, when about 1.5 miles from home, my dashboard lit up like a Christmas tree and the MID began cycling between "Emissions system problem!" and "Electronic emergency brake problem!"

I was about 200 ft from a traffic light when this started and of course the light immediately turned red. After it went green again, I started across the intersection when the e-brake went full ON. I dragged the rear wheels probably about 50 feet or so, so that I could at least get out of the intersection, off the road and into the first parking lot after. As soon as I was off the road I stopped, but the car wouldn't move again at all. It was totally cripped in place, still cycling the same errors on the MID.

I called Acura roadside service, and they sent a guy to tow the car, and that's the last I saw of it. Not hearing back from the dealer I called yesterday at the end of the day and they informed me the tech had not yet found the problem, and that they would call me today as soon as they know what happened and how long it would take, etc. As of now I still haven't heard from them.

I bought the car new and it's still fully within the manufacturer's warranty period, so none of this should cost me anything more than an inconvenience, but having said that I am still hugely disappointed, and never had an issue like this with any Honda product. I planned on keeping this car for a long time, but depending on what they tell me later I may (or may not) reconsider.

Another case of "if it weren't for bad luck, I'd have no luck at all."

jdpdata

Dash lit up like Christmas tree sounds like a 12V battery issue. I had this with my 2020 RLX-SH. Dealer replaced 12V battery under warranty last year. If you don't drive much like I do, (I also work at home) then 12V battery will get drained very quickly. Try to keep your keyfob far away from the car. I notice both my Hybrid 12V batteries died very prematurely. Keyfob might be constantly communicating with car thus draining the 12V battery. Our garage is very close to living room where we keep keyfobs. I moved them further away to bedroom, see how it goes this year.

But your issues sounds difference because you were able to start your car and drive it a bit. Let us know what dealer finds out...

Edit: might be good idea to put your car on trickle battery charger if you don't drive it much. This helps keep that 12V fully charged. Been using on both my cars, no problems at all.

hondamore

I have also experienced the "lit up like a Christmas tree" phenomenon which also turned out to be related to a weak 12V battery.

Unfortunately, modern cars have so many different electronic systems that each use a miniscule amount of power when the car is inactive. When they are added together, they produce still a minor amount of parasitic loss to the 12V battery. If the car is not driven for extended periods, the parasitic loss can cause the 12V battery to become discharged slightly which, over time, weakens the 12V battery shortening its lifespan. If the car is driven infrequently, I agree with jdpdata's suggestion that a trickle charger be used to prevent weakening of the 12V battery.

Of course, we don't know if that is the issue with Dudley Fuddpucker's car. The only incident that I can think of that was remotely similar was experienced by neuronbob years ago, so hopefully he can chime in with what he learned from his experience.

thoiboi

+2 on battery

Dudley Fuddpucker

Well, this is DAMN frustrating. The end of the second day and I heard nothing from the dealer, so I called them, and the full skinny is that by the time the car got to the dealer the errors were all cleared, and they were able to drive the car right into the service bay. He said that the OBD codes had some faults related to coolant, but nothing on emissions or the e-brake, which is what the MID was saying to me.

The implication was that the car was ready to be picked up, but I told him I want them to test it another day. In the end it seems they've done nothing and will do nothing because for all intents the car seems fine now.

This makes me a bit nervous. Remember my e-brake cinched full ON on it's own and did not respond to the switch, even after I stopped and turned the car off and on several times. What would have happened had I been on the highway when this occurred?

If they insist I pick it up tomorrow I am going to make sure they have a full account of my experience on record. I believe I still have another 18 or so months on the warranty, but this is very concerning.

rlx015

Classic dealership: they probably reset the battery, cleared the codes, and all works now... My wild guess says if that is what they did, this issue will probably occur again: and when it does, tow back to the dealer, and at that time do let them know that many are reporting the issue with the 12V battery as the culprit of the issue. I am sure they will be happy to simply swap it under warranty and send you on your way.
I have not experienced it with my RLX SH, but had a similar experience with my previous car, '06 RL where ground connection on battery corroded and lost contact while driving enough to trigger Christmas lights on the instrument cluster.

mrgold35

I'm another (2018) RLX Sport Hybrid owner that had a failed OEM 12v battery with a bad cell at 18,000 miles back in Dec/21. I had X-mas light errors and "U0404-00 ACC may not work with braking system" and "U1100 Gauge control lost communications" issues displayed on the navi screen. Acura cleared the codes, new OEM battery, and zero issues since (now +36,000 miles). My issue was in the middle of the lock-down and wasn't driving the RLX for 3-5 weeks at a time. I figured the battery was already starting to go bad and RLX sat too long with only short trips draining the 12v power to the point of no return.

I've noticed my 19 MDX hybrid and 18 RLX hybrid have regular flooded batteries compared to using AGM for the 3.5L MDX with Auto Stop-Start? I switched to an AGM battery for my 11 MDX Adv+Ent after the OEM battery showing warning signs and only had 15-20 mins of reserve power in a parking lot when I added a dash cam. Absolutely zero issues for +6 years with AGM battery and had plenty of reserve power all day for parking lot mode with my dash cam. I don't know switching to AGM for the Sport Hybrid is A-OK or cause some type of issues with the EV systems? Trickle charger or switching to AGM might be an option if your RLX sits for weeks and/or most of your drives are short distances.

Dudley Fuddpucker

FWIW, with battery issues coming up a lot by many responses I have taken the step of already buying a 12V charger that also does duty as a trickle charger. It already arrived today.

I am still kinda in shock (dismay?) though with the thought that a low battery could cause the parking brake to go full ON all by itself...and NOT respond to the switch.

jdpdata

Today's newer cars with all the electronics on-board will go thru a 12V battery very quickly, I find 2-3 yrs is average life span. If your battery is older than 3 years and you don't drive much, you're taking a huge risk of getting stranded. I see people bragging their battery is 7-8 yrs old, they're on borrowed time IMO. New battery is not that expensive and a trickle charger is cheap. Use it when your car is sitting idle for a long time. Our MDX is on the 3rd battery already. The damn car is only 6 years old! That is unfortunately what happened working at home and not driving much. I put less than 1000/yr with mostly short street driving. Battery doesn't get fully charged if you don't do long distance freeway driving.

DanL07RL

Then you should lodge a safety complaint with the Transportation Safety Administration......force them to address it!

hondamore

Dudley, if your battery is already weakened, then the trickle charger won't really help. The nature of lead acid batteries is that, if they become severely discharged, they never fully charge again. The best thing to do is replace your 12V battery and then start using your new trickle charger to ensure that the new battery never gets serious depleted again. FWIW, when I had my battery issues, the dealership tested the battery and told me it was fine, then when the car lit up again the next day, they finally agreed that the battery should be replaced.

My guess on the issue is that the onboard computer is powered by the 12V battery and when the battery is weak, the computer "fails" which causes the lightshow on the dash and potentially causes very serious issues like the power shutdown that you faced. With this in mind, getting a new 12V battery and then doing everything in your power to maintain its effectiveness are the best and easiest first step to avoid further issues. Some have even suggested routine replacement of the 12V battery every 3 years to ensure that you always have a healthy battery and a fully functioning onboard computer when you press the button to start your car. Again this is just my guess at the issue, but batteries aren't all that expensive, so it may be a good first step in diagnosing your problem.

Good luck and I hope you continue to enjoy your RLX Sport Hybrid.

DanL07RL

Fresh batteries do not need a trickle charge, they store just fine if they are not connected to anything. I disconnected the battery for my Porsche every year for storage and it always fired up.

The car is draining the battery faster than most other RLXs which is a known issue with the cars. This one in particular is harder on batteries....for some reason....and sparing batteries on trickle chargers is not really a good fix, but still maybe a good "guess". Too many "guessers" on this forum.

Get a new battery after there's been a full check out of the electrical system, then simply expect to change them every three years. That's really all you can do.

mrgold35

Goes back to my earlier question of switching to an AGM battery for the Sport Hybrid powertrain to delay or avoid this issue every +/- 3 years in the future? I'm at +5 years with the original OEM battery for my 19 MDX Adv Sport Hybrid; which, extremely surprising since I've always gone between 3-4 years with OEM batteries on my 3 previous I.C.E. vehicles and current RLX Sport Hybrid. Planning to do a "preemptive strike" and replace my original MDX battery soon with aftermarket. Trying to figure out if going AGM will solve future issue down the road or cause any issues with the EV powertrain/components (planning to keep the 19 MDX for another +5 years/+50,000 miles).

vtec_v6

I agree with mrgold35 on this.

Around year 3 or so on oem batteries, I preemptively swap the 12V batteries in all my vehicles with Odyssey AGMs. They are expensive but I've ran them for over 8 years in a vehicle with no issues. Makes life easier--one less thing to worry about.

jdpdata

AGM will last longer but when they die it's abrupt.

mrgold35

Reminds me of my LED 18650 powered flashlight when they work 100% and just die leaving you in the dark with low power.

Still not 100% with understanding if the Acura flooded batteries suck, the Sport Hybrid system is hard on flooded batteries, or both? I'm starting to see two types of batteries with AGM and Pure Lead AGM (sometimes listed as AGM TPPL-thin plate pure lead). Quick reading shows the Pure Lead AGM recharges faster, discharges rate is slower compared to flooded batteries, higher CCA, 3X the life of flooded batteries, and designed against catastrophic failure. I'm right at 26 months with my warranty replacement flooded OEM battery in my 18 RLX and over 5 years with my OEM flooded battery on my 19 MDX Sport Hybrid. Leaning hard on taking a chance and going with AGM for replacements to hopefully avoid @Dudley Fuddpucker catastrophic failure (assuming Acura can't find the exact cause).

jdpdata

Just use a trickle charger, you'll be fine. Replace 12V every 3 years if you don't.

psheu

I recently had a similar experience. It happened after I had my service and the dealership changed my battery for the first time after 4+ years. Same thing, all the lights came on. Took it back and they did a diagnostic on it. It turns out the bad fuel pump is the cause. They changed out the fuel pump and everything is back to normal.

One additional interesting finding. Our car doesn't have an alternator. I think it uses the inverter from the hybrid battery to charge the 12V battery.

jdpdata

That sounds scary? Car dying in middle of the road. Is there a recall out for fuel pumps for our cars?

http://www.urvi.net/forumfiles/SB/B23-038.PDF

psheu

When I asked the dealership for the details of the problem they showed me the main error codes that showed up were the emission problem and fuel problem. These triggered all the other issues like park assist and traction control and all other components. The fuel pump in our car works harder than other cars with switch between battery and fuel and shuts off when the car is in idle. Plus my car has such low mileage (25k from brand new). It surfaced after I done my 3rd service. At first, I thought they gave me a bad battery.

btw, my original battery in this car lasted me 4+ years. Rare for Florida car.

250kmiler

I don't drive my 2018 TLX as much anymore, so the other day my battery actually died at a gas station. Thankfully a passerby gave me a jump. My last dealer service was less than 3 months ago and the battery was fine. The TLX will likely sit in the garage for weeks at a time without driving, so now I'm deciding whether to buy a trickle charger or a battery jump starter. Any recommendations on which is better, or is there a product that can do both?

Dudley Fuddpucker

In the end, the dealership agrees: there were no error codes of any kind, and they chalk it up to low battery voltage. I can kinda buy the reasoning here because I had been travelling the previous 10 days or so, so the car was just sitting in my garage, and this was the first time I had driven since before flying out (and it was a short trip to boot).

So yeah, I don't disagree with the diagnosis, but what I can NOT abide by is the symptom: my parking brake self-cinching in the middle of an intersection and refusing to respond to the switch, totally immobilizing the car? What if I had been on the highway at the time? It would be quite different if I tried to start the car and it were dead, but this was a horrible reaction to low battery voltage.

The dealership only recommended I call Acura NA and file a complaint, which I fully intend to do once I recover from this damn respiratory bug going around.

cidvanski

WARNING..... LONG POST!! I had a different type of failure the other day. I was driving to work in my 2018 RLX Sport Hybrid when I noticed a ticking noise coming from my engine. Two days prior I had my oil changed at a Honda dealership in town because my schedule didn't give me the time to schedule a service appointment with Acura. My codes were B126 on my maintenance minder. They took care of it and told me that no issues were spotted during the courtesy inspection. Anyway, as I continued my commute I noticed that the ticking sound was getting noticably louder, and before I could turn down my stereo to pay closer attention to the noise I heard a pop, and I immediately saw a plume of smoke coming from the back of my car. I pulled over to see what happened. At that time the noise coming from the engine was really loud when I pressed on the gas, and when I got out of the car to inspect the source of the smoke I noticed a significant amount of oil coming from behind the wheel well of the passenger side. I called AAA requesting to have it towed to the Honda dealership that did my oil change, convinced that the damage was caused by a botched oil change, only to get there and find out that the oil leak came from a thrown rod that literally punctured my engine block! The service manager told me that in order to have it repaired that I would need to have it moved to the Acura dealership. They needed to replace the engine and the associated. Cost for that repair according to their estimate would be around 8 thousand! They said that I would most likely be required to pay one thousand to get it repaired. They had a Honda representative look at it and after reviewing my service history they determined that my car was a good candidate for a "good will replacement", and because Acura uses the same criteria that they use to make that kind of determination that once they do their inspection of the car that they should be able to come to the same conclusion. They were right, but their cost estimate was way off! Acura told me that the repair would cost me 13.5k and I would be required to pay 2500 to get it taken care of. I'm currently riding in a 2023 Acura RDX loaner while they wait for the parts (on backorder for an undetermined amount of time). Has this happened to anyone else on the forum? If so, what was your outcome? Honda told me that the engine used for the RLX was known to throw rods and that there were several instances of it happening. I have never heard of this issue. My car has 77k miles and was running fine with no major issues prior to this happening. Please share your thoughts..

mrgold35

I didn't realize the RLX 3.5L DI was so different from the Honda or MDX 3.5L? Do you always use Honda blend oil or full syn (I aways switch to full syn)? I wonder if these types of potential failures "baked into the cake" and show up under certain conditions like we have with RLX 12v flooded battery low voltage problem, oil consumption with gummed up cylinder rings on 2nd Gen 10-13 MDX, and rod bearing wear with 3rd Gen MDX?

Dudley Fuddpucker

It isn't (that different). outside of the obvious item that ours is made in Japan, I believe most everything about our 3.5L is the same as that used in the MDX, Pilot, etc. (not including the new DOHC 3.5L). I think only the cam and VTEC profiles are different (hence the higher HP rating).

Furthermore, everything I read about these SOHC models is that they are as reliable as dirt, with some engineering breakdown sites calling them one of the best V-6s ever made. This makes me wonder if the Honda techs didn't do something (erroneously or otherwise) to instantiate his issue.

1186KA9

Think your mechanic is thinking of the TLX in regards to the connecting rods being a common issue. As many of us know, the TLXs are under a massive recall due to manufacturing errors with regards to the crankshafts and con rods. RLX engines shouldn't have this issue due to being made in Japan. I kinda think that you just got really unlucky here. Maybe someone screwed up servicing this thing in the past? Check your service records to see what type of work was done.

CadiGTi

That had to be frightening and really upsetting barely being able to get the car to move with the e brake fully engaged. Especially after years of reliability. I purchased my 2020 RLX Advance brand new in July 2020. I proactively had the battery replaced a few months ago. I am at 103k miles and knock on wood zero issues. I have the Acura extended bumper to bumper 120k mile warranty so I will reach those miles this year. Soon I will have the major timing belt service etc done. I originally did not plan to keep this RLX past the 120k warranty, but the longer I own this car the more I respect it and love it. I do a lot of long distance travel for my business and really love just how comfortable, pleasurable, efficient, relative cheap to keep, and competent the RLX is. I have a stick shift Corvette and one of the last Camaro SS sticks which I absolutely love, but they are very different cars from the Acura built for different purposes. As long as the RLX is reliable I will keep it as my trusted road warrior business vehicle.

jdpdata

You do alot of long distance driving, so that helps keep 12V charged. For those of us who WFH, dead battery is common issue.

This reminds me of similar issue I had to brand new 2000 BMW 328Ci back in the days. Brand new just drove off dealer lot. Damn thing died mid-way thru a left turn. No e-brake, flashing dash lights, no power steering, everything completely dead. Windows and sunroof couldn't even function..I had to crawl out of the trunk! Thankfully I was able to quickly coast to side of road before a big-rig plowed into me head-on. I would have been creamed!. Shitty German cars, my first and last!

kareshi

Ever since I got tires damage by potholes twice in a month, I am reluctant to drive it for a road trip now

mrgold35

Same for me with potholes. I'm up to one pinch flat with OEM rims and two replacement aftermarket rims with my 18 RLX since Dec/2019. I switched to aftermarket rims because they are cheaper than OEM. I did purchase a 5th aftermarket rim for a full size spare. The full size spare replaced my donut and fits in the trunk.

CadiGTi

Full disclosure I worked for Michelin Tire for 16 years right out of college, they were a terrific and highly ethical company to work for. I spent the last 10 years at Michelin on the General Motors account in quality assurance. I replaced the OEM Michelins on my 2020 RLX with the Michelin Pilot Sport all season 4. I have about 53k miles on them now and within the next 7k miles will replace them. I was tempted to try out the Continental's based on glowing reviews on the RLX threads here, but will stay with Michelin. The main reason is I have never had a blow out with them. I am in DC and the DC beltway, as well as the Baltimore Beltway often, as well as NYC (Brooklyn Belt Parkway, the Staten Island Expressway and the Cross Island). I go up to Detroit annually and even have made treks to Canada with the RLX. Thanks to lousy roads I have badly bent 2 rims I had to have repaired and often have hit jaw breaking potholes and broken parts of the road, but have never blown out a Michelin. Perhaps it's just luck, but I have a high peace of mind level with the Michelins, and the Pilot Sport All Season 4. I also like their wet weather traction and general quietness. When I worked for Michelin it was known in the OEM circles that Michelin more than anyone consistently produced the most uniform tires and had the highest air retention rate of any tire manufacturer due the quality of materials and build quality. When our OEM customers had some high end cars that were prone to shake and vibration and balance sensitivity, they always spec'd Michelin.

Last month at 100K miles. Had the rear bumper touched up from a minor parking lot issue. Overall Amazingly the car looks showroom new. I do all my own detailing since I was 13
These RLX's are like old school Buick's. The modern day luxury car tank

kareshi

If it's not because my tires are new, I actually thought of downsizing to 18" with a 245/45 which gives the identical speed as the 19. I think that would work better. The tires are cheaper too.

kareshi

My winter tires are continental and they are good. Unfortunately they are the ones that got blown too, while my OEM are surviving so far. I also wonder if the continental tires structure is more prone to damage, but it's hard for me to prove it. The holes that I hit were pretty bad anyways