Last Friday, after approximately 20 minutes of highway driving at steady 30-45 mph under heavy rain, I encountered my first issue with my ‘23 ES300h (20 months old / 8k miles). It suddenly started dinging and displaying multiple warning alerts on the dashboard, including the check engine light. One even indicated that the hybrid battery was critically low. Despite this, it appeared to drive normally.

Upon reaching my destination 10 minutes later, I inspected the car for any visible damage and cleaned all bumper sensors, front camera, and the windshield camera area. After restarting, only the "Parking Support Brake Malfunction" warning and check engine light remained.

Once home, I connected my Bluetooth OBD2 with Carista and retrieved the following codes:

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Basic OBD2:
P0572 (Permanent) (Confirmed) - Brake Switch "A" Circuit Low
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ABS:
C1425 - Open in Stop Switch Circuit
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I cleared the codes and have continued driving without any issues so far. The check engine light has not reappeared. However, my Lexus app under the health section still displays the following alerts:

• Pre-Collision System
• Parking Brake System
• Advanced Ultrasonic Detecting and Ranging System

I looked into it online, and it seems to be related to the brake pedal switch. Anyway, I’m planning to schedule a Lexus dealer visit later this week.

• Could they still pull the codes after I reset them?
• Could this just be one-time issue because of the heavy rain? (I did not cross any flooded or partially flooded area, just heavy pouring rain on highway)
• Any suggestion to look or ask dealer for?

Thanks!

 

I would suspect moisture entering an electrical connection. To find it start by cleaning and inspecting the most exposed connectors. I can see where the tech might want to throw parts at it and might even fix it by disconnecting and re connecting the problem connector. Good luck.

 

I think you have a bad brake light switch. Very cheap part and easy to replace.

 

I can't help but think the heavy rain, and probably water ingress somewhere, caused your dash lights. I would not expect a two year old brake light switch to fail so early, but it's possible.

Taking it into the dealer is a good move. Let them troubleshoot. They should be able to pull historical codes even though you cleared the active codes. Good luck.

 

Thanks to all! I have an appointment on Wednesday to have this checked. However, I expect the dealer to dismiss it as an intermittent issue, with no resolution provided. But at least a log will be generated. Interestingly, the "Health Alert" no longer appears in the Lexus app.

I suspect the heavy rain may have played a role, perhaps some stubborn dirt affecting the camera or sensors. But I find it hard to believe water ingress is the culprit, especially in such a new car, given that I didn’t cross through any flooded area. I expect my vehicle to perform reliably in rainy conditions. Or as suggested its just a mfg. bad brake light switch.

 

Keep us updated. that would certainly leave me rattled but at least you continued to drive to safety. reminds me of my ES300h when I had it. I had it stall on two occasions (no rain) while entering an intersection (I posted about this long ago when I had the car). Basically there was no response from the gas pedal as i rolled into the intersection. floored it, stabbed the pedal, nothing, for about 2 seconds. i looked down at the gauges in confusion as i was rolling (felt like it was in neutral). then the car finally woke up and accelerated after what felt like an eternity.

It happened just 30 seconds after startup, leaving my place of work. I emailed my lexus dealer explaining what happened and they ignored me. then i asked a subsequent time at another visit and they said they couldn't reproduce the problem. so yeah it was and is a mystery to this day. its almost as if the computer fell asleep. no lights or errors, or anything.

 

Water moisture for sure.
I have a Rav4 that did the same thing last winter when I drove over a rather deep puddle. 5 minutes after driving over it and my dash lit up like a German car's dash. Scared the hell out of me.
I left a blower fan blowing air in the engine compartment for the next 2 days. Most lights went away but the O2 sensor code keeps tripping. I thought it needed replacement. Next couple of days I left the hood open and aimed for the sun light. Thankfully the code too went away.

 

It could be due to moisture, though I don’t recall passing through any deep or shallow puddles. Given the heavy rain, it's not entirely out of the question, but I wouldn’t expect a brand-new Lexus car to have issue while raining.

Anyway, as expected, my concern was dismissed with the following remark: "Performed health check with scan tool. No DTC's found stored in ECM. Performed road test, was not able to duplicate customer concern at time of service. Found vehicle operating as intended" I do find it quite odd that no history of the issue was pulled.
Finally, was also told by the service advisor that to never turn off the check engine light again or try to fix any issue while under warranty to prevent a warranty fix decline. Does this make sense?

 

Makes a little sense. If it's under warranty, do let them fix it. If you erase codes that trip and you bring it in the dealership, it makes their troubleshooting all that much more difficult. Logs help technicians solve the problems.

They shouldn't decline your warranty for simply erasing codes. Unless it's specifically stated on the long document we all sign but never read.
Dealerships are always looking out for ways to weasel out of repairs that come out of their pockets.

 

Check out these posts, may be helpfull:

https://www.clublexus.com/forums/es-...unction-2.html
https://www.clublexus.com/forums/es-...l#post11205842

 

I had a printed copy of the OBD2 troubleshooting codes logged at the time, along with a printout of the Lexus App Health alert. They declined to accept the printout, which is understandable since anyone can generate a bogus one. However, I had expected that modern ECU's (specially high end luxury brands) would retain a history log of at least the most recent logged codes.

Timing presents another challenge. They require the check engine light to be present for service, yet at my dealer you can't just show up without an appointment. In some cases, like yours, the light may turn off on its own if the code is no longer present after a few days. In my case, driving since last Friday until today, with the check engine light on, the persistent DING, and the multiple messages on the dash would have driven me crazy. It's not just one small CEL anymore.

 

Maybe get a video recording of yourself connecting the code reader and reading the code. Present the recording to the service center. If they still won't accept it take it up the corporate ladder. The more evidence you have the harder it is for them to deny.
If all else fails contact Scotty Kilmer. He's had a few videos where Toyota denied the customer and after he released the video, Toyota came out licking the customer's behind. lol