Here you can discuss the technical ins and outs of the 4th generation 2016 Prius and related hybrid components. Mon, 16 Mar 2026 17:46:16 +0000 Mon, 16 Mar 2026 17:46:16 +0000 PriusChat https://priuschat.com/forum/gen-4-prius-technical-discussion.152/ Sat, 14 Mar 2026 23:21:33 +0000 https://priuschat.com/threads/how-to-add-a-light-which-turns-on-with-drl-or-headlights.258673/ https://priuschat.com/threads/how-to-add-a-light-which-turns-on-with-drl-or-headlights.258673/ invalid@example.com (PAW) PAW I want to add an LED light which would come on when the DRL/headlight is turned on. Otherwise it should remain off.
(for discussion let's ignore the new light's amps/watts).

Do you have ideas of how to do this?

I am able to tap into the DRL and headlight wiring to get power for the new light when they are turned on, but I'm pretty sure wiring the DRL and headlights together to the new light will cause "bad things to happen."

I read somewhere about the idea of using...

How to add a light which turns on with DRL or headlights?]]> 6 Mon, 02 Mar 2026 06:58:17 +0000 https://priuschat.com/threads/2017-fuel-tank-sloshing-sound.258741/ https://priuschat.com/threads/2017-fuel-tank-sloshing-sound.258741/ invalid@example.com (Purrius) Purrius

(Please click here if video doesn't load)

I've never noticed it before, which doesn't necessarily mean it's abnormal, but I'd still like to ask just in case something might be secretly going cattywampus in...

2017 - Fuel Tank(?) Sloshing Sound]]> 11 Fri, 27 Feb 2026 22:01:08 +0000 https://priuschat.com/threads/multi-switch-84010-47490.259073/ https://priuschat.com/threads/multi-switch-84010-47490.259073/ invalid@example.com (PAW) PAW This version of the switch has both the HUD (Heads Up Display) and AHB (Automatic High Beams) buttons.
The switch has 10 pins connected to a 12-pin connector.

This is what I think I know so far:
Pin # Wire Color (purpose)
Pin #1 Green (?)
Pin #2 ?
Pin #3 ?
Pin #4 Black (?)
Pin #5 White/Black (ground)
Pin #6 Red (power)
Pin #7 ?
Pin #8 ?
Pin #9 ?
Pin #10 Yellow (powers the AHB LED light)

Appreciate any help. Thank you]]> 2 Mon, 19 Jan 2026 22:50:25 +0000 https://priuschat.com/threads/gen-4-12-volt-battery.190679/ https://priuschat.com/threads/gen-4-12-volt-battery.190679/ invalid@example.com (padroo) padroo
From what I have found it looks like the battery out of a Chevrolet Spark will fit and work.
Here is some information/

BCI Group Size: 140R battery 13-17 Chevrolet Spark...

Gen 4 12 Volt battery.]]> 200 Sun, 18 Jan 2026 19:30:58 +0000 https://priuschat.com/threads/18-prius-popping-sound-from-rear-of-engine.258691/ https://priuschat.com/threads/18-prius-popping-sound-from-rear-of-engine.258691/ invalid@example.com (Nash700) Nash700 Recently there is a popping sound coming from the return lines from the converter. It sounds like maybe a misfire or a converter damaged.
I have scanned it multiple times and it is not a misfire. It is not an engine rattle or gargle of antifreeze….it literally sounds like someone popping popcorn coming from the pipe.

I’m about...

18 Prius popping sound from rear of engine]]> Thu, 15 Jan 2026 12:06:59 +0000 https://priuschat.com/threads/exhaust-noise.258644/ https://priuschat.com/threads/exhaust-noise.258644/ invalid@example.com (Jacob156) Jacob156 1 Thu, 15 Jan 2026 05:35:04 +0000 https://priuschat.com/threads/gurgling-exhaust-noise.258647/ https://priuschat.com/threads/gurgling-exhaust-noise.258647/ invalid@example.com (mpg1) mpg1
Gurgling exhaust noise]]> 1 Wed, 14 Jan 2026 13:44:52 +0000 https://priuschat.com/threads/underhood-12v-for-drls.257429/ https://priuschat.com/threads/underhood-12v-for-drls.257429/ invalid@example.com (MrFixer) MrFixer 6 Thu, 08 Jan 2026 00:49:15 +0000 https://priuschat.com/threads/prius-suddenly-dies-after-head-gasket-job.258531/ https://priuschat.com/threads/prius-suddenly-dies-after-head-gasket-job.258531/ invalid@example.com (wrendog) wrendog
Prius suddenly dies after head gasket job]]> 3 Tue, 06 Jan 2026 14:10:55 +0000 https://priuschat.com/threads/multiple-error-codes.258520/ https://priuschat.com/threads/multiple-error-codes.258520/ invalid@example.com (Yrps) Yrps
- Antilock Brake System Malfunction Visit Your Dealer
- Power Steering Malfunction Steering Power Low Visit Your Dealer
- Pre-Collision System Malfunction
Visit Your Dealer

These popped up and a much more.i unplugged the dashcam in the fuse box and disconnected the 12V battery and tried clearing codes but no luck! All codes are still popping...

Multiple error codes]]> Wed, 24 Dec 2025 15:19:08 +0000 https://priuschat.com/threads/caliper-bracket-torque.232036/ https://priuschat.com/threads/caliper-bracket-torque.232036/ invalid@example.com (rlecastro7) rlecastro7 Thanks]]> 8 Tue, 23 Dec 2025 20:16:41 +0000 https://priuschat.com/threads/prius-scraping-on-ground-which-splash-guards-need-replacing.258360/ https://priuschat.com/threads/prius-scraping-on-ground-which-splash-guards-need-replacing.258360/ invalid@example.com (CaramelNectar2017) CaramelNectar2017
I have a Gen 4 Prius Prime Advance and noticed some scraping. Taking a look at the underside, I noticed the splash guards are hanging loose. No amount of pushing it back in helps, I'll need to replace it.

I'm just wondering which splash guard to buy exactly: front splash guard, driver side splash guard, or both?

View from the side: View attachment 286660
View from the front: View attachment 286661]]> 3 Fri, 12 Dec 2025 22:41:56 +0000 https://priuschat.com/threads/is-one-of-my-tps-sensors-failing-or-something-else.257941/ https://priuschat.com/threads/is-one-of-my-tps-sensors-failing-or-something-else.257941/ invalid@example.com (ticedoff8) ticedoff8 Replaced the tires at 65k and all has been well.
I'm trying to figure out if one or all my TPS sensors are failing or it's something else.

About 2 months ago, before a 300mi trip, I topped off the pressure on all 4 wheels to 37psi and it was around 65F ambient when I pumped them up. I like this pressure when the weather cools down and it gets up to 39psi after driving (I use 34psi in the summer).
I was driving over a mountain highway from the...

Is one of my TPS sensors failing... Or something else?]]> 9 Sun, 30 Nov 2025 07:52:28 +0000 https://priuschat.com/threads/inverter-converter-in-2017.257402/ https://priuschat.com/threads/inverter-converter-in-2017.257402/ invalid@example.com (docsam) docsam
inverter converter in 2017]]> 7 Fri, 28 Nov 2025 19:45:52 +0000 https://priuschat.com/threads/any-downsides-to-using-agm-12v-battery.256754/ https://priuschat.com/threads/any-downsides-to-using-agm-12v-battery.256754/ invalid@example.com (MrFixer) MrFixer 5 Fri, 28 Nov 2025 12:02:31 +0000 https://priuschat.com/threads/can-i-change-the-speedometer-correct-factor.256354/ https://priuschat.com/threads/can-i-change-the-speedometer-correct-factor.256354/ invalid@example.com (ticedoff8) ticedoff8 Is there a setting in any of the car's ECUs that I can change (and write) for "Speedometer Correct Factor"?

Since I changed the tires, the speedo readout is about 4% lower than my phone's GPS says (Example: 55MPH speedo v. 53.5 on GPS. 77MPH on the speedo v. 74.5 on GPS).
It's always been a little off even with the tires that came new with the car (I bought the car new from the dealer), but now it's bugging me.

I have an...

Can I change the Speedometer Correct Factor?]]> 8 Fri, 28 Nov 2025 02:40:29 +0000 https://priuschat.com/threads/prius-differential-vs-transmission.231419/ https://priuschat.com/threads/prius-differential-vs-transmission.231419/ invalid@example.com (pnw_jk) pnw_jk
Does the Prius transmission and front differential use the same fluid reservoir? Also, is there a rear differential that I should be looking at to change the fluid of?]]> 29 Sun, 23 Nov 2025 19:53:57 +0000 https://priuschat.com/threads/gen4-2016-187-000km-ticking-noise-on-cold-idle.257942/ https://priuschat.com/threads/gen4-2016-187-000km-ticking-noise-on-cold-idle.257942/ invalid@example.com (Ivan92) Ivan92
The ticking sound itself is similar to a hydraulic lifter tick, or a loose timing chain/tensioner.

When I changed engine oil 0w20, mechanic told me that it should not tick like that, he also said that hes not surr wheres the problem, he said it might be a bad lifter, and told me just to...

Gen4 2016 187.000km ticking noise on cold/idle]]> 5 Fri, 17 Oct 2025 19:13:29 +0000 https://priuschat.com/threads/clunk-sound-in-rear-shock.257478/ https://priuschat.com/threads/clunk-sound-in-rear-shock.257478/ invalid@example.com (cbracer) cbracer
I made a video of this but could not upload it to my message nor create a link since it's my first day. I...

clunk sound in rear shock ?]]> 3 Thu, 09 Oct 2025 12:09:42 +0000 https://priuschat.com/threads/hybrid-battery-temperature-and-fan-speed-hybrid-assistant.249434/ https://priuschat.com/threads/hybrid-battery-temperature-and-fan-speed-hybrid-assistant.249434/ invalid@example.com (andywhy) andywhy
I have a Lexus UX which is gen4 based and I wondered if anyone had any issues with their hybrid battery overheating on long distance trips and long regens, and the fan not increasing in speed appropriately?

During a recent long trip there were a lot of long regen periods which meant that the battery was increasing in temperature quicker than normal. It normally sits around 38 degC, but the battery eventually hit 45 degC which caused it to start limiting charge and discharge power....

Hybrid battery temperature and fan speed (Hybrid Assistant)]]> 40