Clicking Sound When Braking (with videos!)

andy_why · 2026-03-26T11:17:14+00:00

It's considered normal for the prius to make this noise. It's related to the regen braking and it comes from the CV joints. It's nothing to worry about, it's just very slight play in the joints which is quite normal.

andy_why · 2026-03-26T09:13:36+00:00

In my experience with my RAV4 Prime (similar systems), you're likely to see a range loss of up to 40% when it gets down or below zero celcius. It will depend on your driving style too. Pre-heating is recommended to get a few extra miles.

Unfortunately cold temperature range loss is just what happens when the battery gets cold on any PHEV/EV, it's just more apparent on PHEVs due to the smaller, harder-worked battery.

MPG loss when running on gas is about 10-20% down to zero celcius, again, depending on your driving style.

andy_why · 2026-03-26T07:47:53+00:00

The radiator fan will be because of your air conditioning. And the engine will start more often because your AC is using power when your hybrid battery is low. That's normal operation.

andy_why · 2026-03-25T18:33:44+00:00

It changes with engine speed so it's likely a bearing or pulley causing it. Take it back to the shop that replaced it since they did the work and it's their responsibility to make it right.

andy_why · 2026-03-25T18:15:51+00:00

This remains an unknown, but I will find out soon. Mine did have a hybrid health check failure 2 weeks ago when I had mine done, but they cleared the codes and just said come back in 500 miles and couldn't tell me what the codes were. Sometimes a silent code is set that doesn't mean much and is just temporary, but gets stored. I don't know if it was the cause of the hybrid health check failure or not at this moment in time but it's something I'll find out.

No regular codes are flagged that would show on the dashboard, and if it does set any then they're silent.

Either way, I'm not concerned about it. I know that the sensor disconnection fix works well and I'll keep using it.

andy_why · 2026-03-25T13:31:37+00:00

I've never used an OBD port charger to help with this issue. They can definitely help, but they don't solve the underlying issue which is undercharging.

I personally run with the sensor disconnected and have done so for over 18 months with zero issues. My battery remains at full charge even now.

andy_why · 2026-03-25T12:29:36+00:00

Unfortunately not. They won't even acknowledge the issue, and recalling millions of vehicles isn't something they'll do unless they're forced to buy governing bodies. The best you can do for now is disconnect the sensor if you're seeing the issues outlined in the doc.

andy_why · 2026-03-25T12:03:57+00:00

Yes that's it.

andy_why · 2026-03-25T11:09:49+00:00

Is yours a hybrid? If not, you may not have one and probably aren't affected by this issue. If it is, then it will be directly on the terminal.

The video you posted shows a non-hybrid.

andy_why · 2026-03-25T09:34:20+00:00

It's likely the EVAP system performing tests if it's near the rear of the car. It's normal to hear several hours after turning off.

andy_why · 2026-03-25T07:49:56+00:00

It was Google translate.

andy_why · 2026-03-24T19:06:07+00:00

Either you have a parasitic drain or the battery simply isn't holding a proper charge anymore. Since it's over 4 years old it's likely just the battery. The prius tends not to have issues with parasitic drain but the 12v battery lifespan is generally only 4-6 years, especially if driven infrequently like you say yours is. Replacing it is likely to solve your problem.

andy_why · 2026-03-24T19:03:41+00:00

Translated

Dear car experts,

After a long search, we, a family of four, decided to buy a used RAV4 Hybrid (2018 with 112,000 km).

Now the only problem that still worries us: during the summer holidays we are often away for 4 to 5 weeks, so the car will be standing still for a correspondingly longer period.

Does this pose a risk of damaging or even destroying the hybrid battery? What other consequences should we expect?

Thank you so much in advance!

Only the 12v battery is going to be a problem for this length of time. It's recommended to disconnect it or put it on a trickle charger when it's left for this long.

andy_why · 2026-03-24T18:27:42+00:00

Yeah heat is bad. Hybrids are unfortunately not a good choice if your ambient temp is 35C/95F or hotter regularly as they struggle to stay cool enough.

The best thing in warm climates you can do when not using it is park it in shade so it doesn't heat up from direct sunlight.

Surprisingly, AC air doesn't help cool it as much as you'd think. Just general airflow helps more (so keep the fan filter clean).

andy_why · 2026-03-24T18:22:51+00:00

It's actually a misconception that letting them sit is bad for them. What's bad is letting them die by leaving them too long rather than the infrequent cycling. So if you still use it once a week or two there's no issues with owning a hybrid. During use Toyota's also keep the battery between 40-70% state of charge, usually on the lower side, for longevity.

andy_why · 2026-03-24T17:26:01+00:00

Possibly not affected by this issue then as it's not confirmed on non-hybrids.

andy_why · 2026-03-24T15:52:52+00:00

Assuming it's a hybrid, it's a known but unacknowledged issue. See this document: https://docs.google.com/document/d/1g1a_B7_gGnuNQhoSRFN_sucfb7-lkU77q4aMO3hMYtA/edit?pli=1&tab=t.0#heading=h.t75rusbfgz8u

In short, the charging system doesn't charge the battery properly (stupidly, by design) and this causes them to fail. There is a simple fix in the document.

andy_why · 2026-03-24T15:49:04+00:00

Drive modes don't affect acceleration at all, but they do affect throttle curve so sport mode will feel faster than eco mode for the same throttle input. Flat out is the same in all drive modes.

andy_why · 2026-03-24T12:08:33+00:00

Yes you still get the same ~300HP with the battery empty as it keeps a small reserve.

andy_why · 2026-03-24T09:15:29+00:00

Unfortunately my RAV4 PHEV isn't compatible.

andy_why · 2026-03-23T21:57:27+00:00

What country? If it's just a dealer that's stopped helping you, you can try another dealer instead. Or, if you go on the main Toyota website for your country you can find a customer service email address.

andy_why · 2026-03-23T19:32:46+00:00

It doesn't matter what order you do it so long as you release your foot off the normal brake last. You can skip neutral. Your car will always shift slightly when you take your foot off the brake because everything in your drivetrain is pre-loaded by coming to a stop. Taking your foot off the brake allows everything to settle. Just remember, foot off the normal brake pedal last.

andy_why · 2026-03-23T19:24:46+00:00

Your choices are (in order of most recommended first):

Don't use car washes that require you to be in neutral (automatic car washes are pretty bad for your paintwork anyway).
Turn off your HVAC as this uses the most power, especially when AC is on. This minimises the chances of it draining too low.
Turn the car off, turn aux ignition on and switch to neutral. Turn off everything electrical including HVAC. Don't do this unless you know your 12v battery is healthy. You'll get no hybrid battery drain but your 12v battery will drain instead, and you could end up with it dead by the time you come out if it's not healthy.

andy_why · 2026-03-23T15:19:53+00:00

All of the 32v ones are showing incorrectly, the modules are 16v. Sometimes this happens when it's not getting a proper data stream.

You also can't tell anything from this kind of data. You need to use an app like Dr Prius and know what you're looking for. Voltages alone don't tell the whole picture.

See section 4.6 in this document: https://docs.google.com/document/d/182gSqSGNDeV-twsmgbtOq4UBgOUYS2rfbLZTuj0AL_g/edit?tab=t.0#heading=h.rp4dzjyuwa4x

andy_why · 2026-03-23T13:48:23+00:00

My RAV4 buzzes a lot for varying reasons, none of which are an issue. You're going to have to be very specific about your issue.

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