Gen 4 Prius Malfunctions - Visit your dealer

[thecaretaker]

Sitting in Tesco car park waiting for my wife and the following alerts flashed up:

ICS Malfunction - Visit your dealer
Anti-lock brake Malfunction - Visit your dealer
Lane Depart Malfunction - Visit your dealer
Pre Crash Malfunction - Visit your dealer
Breaking Power Low - Visit your dealer

These have remained displaying. The brake pedal does feel a bit odd when pressing it to start the car.

I've checked the brake fluid which is on the MAX line (That wasn't easy to get at hidden under the wiper housing).

Anything else I should check before taking it to Mr T?

[thecaretaker]

I do hope it is not this problem... This guy has had a terrible time with the anti-lock brake malfunction.

https://priuschat.com/threads/antilock-brake-system-malfunction.174302/

[PeteB]

Yes, this happened to me last year in May/June when the car was almost a year old and the 12V Battery was failing.  The car was at 14-15,000 miles when it happened.

Had you been using Accessory mode or IGN mode (i.e. warning lights on but not READY)?  I got this when the 12V went very low, and a few times I had to use a jump starter (I keep one of the tiny ones in the seat-back pocket).

I also got a couple of other messages (and the MIL light and triangle on):

• Hybrid System Malfunction
• Intelligent Clearance Sonar Malfunction

Regen didn't work properly until the warning lights went out and cruise control wasn't available either.

Things returned to normal after a few restarts, 2 or 3 the first 2 times, and 13 on the third occasion.

Of course, you may have a different problem, but I'd start by checking the voltage on your 12V Battery after the car has stood for a while (and not in READY mode as the HV Battery provides a charge current to the 12V battery when the car is on).

My dealer replaced the battery under warranty and I've had no further problems (now a 26 months old and 30k miles).

[thecaretaker]

I had driven to Tesco, a journey of about 2/3 miles and sat in the car park for about 10 mins before the warnings sounded. I just pulled up and left it in 'P' with the engine cutting in and out. Although I had not driven the car for 3 days.

I think it is a problem with the brakes as the foot brake doesn't feel right. It is very hard at first but then sinks to the floor when I put my foot on it. Driving home it seemed to work as normal.

Turning the ignition off and back on did clear the warnings on one occasion, but then came back on after 2 mins or so and now seems to be on permanently. I'll see what it is like in the morning.

[TheProfessor]

If the warnings came back it means the fault is still there or has reoccurred for sure.

If the brake pedal sinks to the floor it can often mean a master brake cylinder failure or pressure loss in the system. This aligns with one of your warning messages too. In the Prius I would imagine it could also be related to that electric motor you hear running for a second that generates the brake system pressure which would normal be always generated by the ICE in a traditional car. As all the other error messages relate to a system that uses the brakes in some way, I imagine it's a single brake issue.

Whatever it is, when warning messages come up that mention the brakes, don't second guess them or let someone unqualified to work on a Toyota hybrid braking system try and fix it. Drive very very carefully, or get towed, to an authorised Toyota place.

[thecaretaker]

16 hours ago, PeteB said:

Yes, this happened to me last year in May/June when the car was almost a year old and the 12V battery was failing.  The car was at 14-15,000 miles when it happened.

 

Hi PeteB,

Just an update, I drove to the Toyota dealer this morning, on the way I noticed all the warning messages had dropped off apart from the Anti-lock Brake warning which was still showing when I parked at the dealers. I turned the ignition off, waited until the screen went blank and started up. No errors. So got to think this may well be what PeteB had said on the forum 🙂

So, I went round my parents and offered to take them out for a drive (with the intension of making sure the 12v Battery got a good charge). I covered 45 miles with no problems at all. We stopped off for coffee, I spent an hour round their house and then drove back to mine. No sign of any warning lights.

So, I thank you very much indeed. You have saved me an unnecessary time wasting visit to MrT's. Who knows how many days they would have kept my car trying to track this issue (going on their previous track record).  

If it ever happens again, I shan't be so alarmed and will look at the Battery first. My fault for not driving my Prius enough and only doing a few very short journeys. I shall tell my wife, the car is telling me I should get out more!

[QuantumFireball]

It might be worth having some way of checking the 12V Battery voltage to keep an eye on it. You can get a multimeter and either connect it to the Battery in the boot, or jump start terminals under the bonnet; or the Hybrid Assistant app with an OBD-II dongle will also tell you.

[TheProfessor]

 

 

 

connect it to the battery in the boot

 

On the Gen 4 the 12V Battery is in the engine compartment again.

 

 

 

[QuantumFireball]

Oh, that makes it easier so!

[PeteB]

I bought one of these:

https://www.ebay.co.uk/itm/3-in-1-Digital-LED-USB-Car-Charger-Voltmeter-Thermometer-Car-Battery-Monitor-UK/282595713472?hash=item41cc0461c0%3Ag%3AyHoAAOSw~~NbYy9y&_sacat=0&_nkw=VST-706+12V+USB+Digital+Voltmeter+Thermometer&_from=R40&rt=nc&_trksid=m570.l1313

It's not very useful in the front lighter socket because of it's location on the Gen 4, but I pop in the the rear socket with the car in ACCessory mode, and it gives a voltage readout.

[thecaretaker]

1 hour ago, PeteB said:

I bought one of these:

https://www.ebay.co.uk/itm/3-in-1-Digital-LED-USB-Car-Charger-Voltmeter-Thermometer-Car-Battery-Monitor-UK/282595713472?hash=item41cc0461c0%3Ag%3AyHoAAOSw~~NbYy9y&_sacat=0&_nkw=VST-706+12V+USB+Digital+Voltmeter+Thermometer&_from=R40&rt=nc&_trksid=m570.l1313

It's not very useful in the front lighter socket because of it's location on the Gen 4, but I pop in the the rear socket with the car in ACCessory mode, and it gives a voltage readout.

Thanks, just purchased one!

[thecaretaker]

Just spotted one of these. Should be ideal for a Prius cup holder!

[thecaretaker]

On ‎8‎/‎14‎/‎2018 at 2:44 PM, PeteB said:

I bought one of these:

https://www.ebay.co.uk/itm/3-in-1-Digital-LED-USB-Car-Charger-Voltmeter-Thermometer-Car-Battery-Monitor-UK/282595713472?hash=item41cc0461c0%3Ag%3AyHoAAOSw~~NbYy9y&_sacat=0&_nkw=VST-706+12V+USB+Digital+Voltmeter+Thermometer&_from=R40&rt=nc&_trksid=m570.l1313

It's not very useful in the front lighter socket because of it's location on the Gen 4, but I pop in the the rear socket with the car in ACCessory mode, and it gives a voltage readout.

Hello PeteB,

What kind of voltage do you get in Accessory mode? Mine starts at 12.0v and drops to 11.7-11.8 in about 45 seconds. But when I turn the Start to ON I get a steady 13.8v

Reading on the web, it says a healthy Battery should output 12.6v in accessory mode and anything from 13.8-14.7 when running. Would you think my Battery is a bit on the low side?

I've made a little clip and uploaded it to youtube here. The text tells you what is happening (no sound). 

 

[PeteB]

12 minutes ago, thecaretaker said:

...What kind of voltage do you get in Accessory mode? Mine starts at 12.0v and drops to 11.7-11.8 in about 45 seconds. But when I turn the Start to ON I get a steady 13.8v

Mine stays at 11.7 for quite some time in ACC mode, which seems to be fairly normal on my car.  I don't have any problems at this level.  When on (READY mode), 13.8 is what's supplied to the Battery from the HV system, so doesn't tell you anything about the 12V Battery.

The Battery that failed was giving below 10V when the car had been left in ACC for just 2-3 minutes - it tried to operate the brake hydraulic pump but wasn't able to finish, so was not able to start the car.  Problem with the Hybrids is that apart from remote locking sensors, alarm, interior lights, folding mirrors, etc, there are pumps that operate as soon as you open the car that can push a failing 12V battery over the edge.

[thecaretaker]

So looks like mine is working normally then. Thanks for that, much appreciated.

[PeteB]

2 minutes ago, thecaretaker said:

So looks like mine is working normally then. Thanks for that, much appreciated.

yes would seem so.  I've certainly had no problems since my Battery was replaced in July last year, 13½k miles ago.

As it happens, mine is going in for it's 30k service in the morning.

[kithmo]

2 hours ago, thecaretaker said:

So looks like mine is working normally then. Thanks for that, much appreciated.

Yes, taking into account the stuff that's drawing current when in accessory mode, 11.7 volts sounds ok.

do you have a link to that cup holder sized usb/twin power socket/voltmeter thingy.

[thecaretaker]

On ‎8‎/‎15‎/‎2018 at 6:21 PM, kithmo said:

Yes, taking into account the stuff that's drawing current when in accessory mode, 11.7 volts sounds ok.

do you have a link to that cup holder sized usb/twin power socket/voltmeter thingy.

Yes, here you go: https://www.amazon.co.uk/gp/product/B01GHR36VY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

[kithmo]

6 hours ago, thecaretaker said:

Yes, here you go: https://www.amazon.co.uk/gp/product/B01GHR36VY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Thanks for that Paul, I've just purchased it.