Ready Light - Not Ready!

[timberwolf]

<snip>

Car was taken to service today and after diagnostic checks nothing recorded in the ecu and battery is charging at 14.2

I have raised the issue about replacement battery but they feel it does not need changing at this time because of the high charge rate, <snip>

Interesting logic! :-( I don't think it can really be used to say too much about the state of health of your 12V Battery. It does tell that your Prius charging circuit is supplying 14.2 V.

The DTC (Diagnostic Trouble code) is an interesting one, they wouldn't be stored if the 12V Battery has gone flat, as you've got no power. Also, I think some DTCs are cleared after the car has been started three times.

How was the charging voltage measured? According to one post I found, the Gen 3 will always set the higher charging voltage when the car is in Ready and Park.

Measuring the health of a 12 V Battery is tricky, so I'm not surprised the garage decided to baffle you with bull instead.

[Grumpy Cabbie]

Interesting logic! :-( I don't think it can really be used to say too much about the state of health of your 12V battery. It does tell that your Prius charging circuit is supplying 14.2 V.

The DTC (Diagnostic Trouble code) is an interesting one, they wouldn't be stored if the 12V battery has gone flat, as you've got no power. Also, I think some DTCs are cleared after the car has been started three times.

How was the charging voltage measured? According to one post I found, the Gen 3 will always set the higher charging voltage when the car is in Ready and Park.

Measuring the health of a 12 V battery is tricky, so I'm not surprised the garage decided to baffle you with bull instead.

lol they're still at it arn't they!

This is like checking a traditional cars 12v Battery when the engine is running and the alternator is providing it with a full charge. You'd have thought Toyota dealers would already understand the Prius enough to work out that the engine doesn't need to be running for the system to be providing charge to the 12v. Even if you disconnect the 12v whilst at your dealers, it won't provide an accurate reading as the car will just have been driven and the 12v nicely topped up.

The best way to see the capacity of your 12v is to leave the car overnight and then check it BEFORE putting the car in Ready mode. As soon as the car goes into Ready the system starts to charge the 12v automatically.

Probably mentioned this before but if you don't have a volt meter (dead cheap to buy), leave car overnight (or 2 days preferably), then get in, put in ACC mode - NOT Ready mode and then wind all windows down and back up together. If the interior lights go really dull and the windows really struggle then you have a 12v issue. If they whizz up and down as if all is normal (like the would in Ready mode), then your 12v is ok.

[johalareewi]

Incidentally on the service sheet it records oil changed and mobil o.2 used. Queried it and mechanic said its the norm now?

For a gen3, the oil should be 0w20 fully synthetic.

Not sure what Mobil o.2 is.

Mechanic saying 'its the norm now' sounds like BS.

Perhaps parts king can confirm?

Loads of threads on here such as...

http://www.toyotaownersclub.com/forums/index.php?showtopic=123645

http://www.toyotaownersclub.com/forums/index.php?showtopic=116432

[robbo40]

have queried the oil again with the service department and currently awaiting an answer from the Service Manager oil used is showing on invoice as Mobil 0.20w

[Grumpy Cabbie]

Then that's the correct (and expensive) oil for the gen3 2009- and optional for the gen2 2004-2009. :)

Not sure I'd use it in a gen2 with high miles that's always used 5w30 though. The US forum has reported a slight increase in fuel economy on gen2 that have tried 0w20 BUT some higher mileage ones have increased oil consumption too.

[Big Peter]

Has anyone else had the following issue. Every so often when I press the start button everything lights up except the Ready light. I then have to switch off and start again, and it usually comes on the second time but very, very occasionally the third or fourth.

2 weeks ago we purchased off our local Toyoya Dealer a 6month old 10th Anniversary Prius with 3500 miles on it, it has only been used by the dealer as a potential customer test car. That evening I went out to drive it and it wouldn't go into READY mode. I contact AA through Club Toyota and was fixed with seconds of the AA guy arriving. He used the jump connector in the engine fuse box and said expect it to happen again as once it goes a new Battery will be required.

I contacted the dealer the next day and informed them. With 1 week it happened another 2 times, I just used my Battery booster to charge the Battery. I complained and they fitted a new battery at the dealer within 2 hrs of me "talking" to them down the phone. They got one send down from up the line VERY fast as they had no stock. They also said this was rare, but after readign on PriusChat Forum there seems to be an issue with these batteries and LOTS of owners in USA are fitting Optima batteries to them as they actually do a direct replacement battery for the Prius, but its about £!30.

[Grumpy Cabbie]

I'd say that the 12v is fine so long as it is looked after. Once any 12v lead acid Battery is allowed to fully discharge (such as sitting on a dealers forecourt for 6 months) it is knackered, shot, no use. It will charge up again but will be internally damaged and will fail again soon after. Once you start needing to 'top up' a 12v with a Battery charger it's on its last legs.

Cars used for taxis will go through 12volts very quickly - some makes of car going through them in 6-12 months, others lasting years. But I know from own experience that look after them and they'll look after you, but once they've gone bad, they're bad.

[robbo40]

The oil supplied is the official Toyota for the car, the mechanic has entered incorrect details......one new Battery fitted!

[Parts-King]

We stock the batteries, I have sold two this week!

On a warranty note we have a Battery gizmo, it's plugged onto the Battery, if it says it needs changing then it is changed, if it says Battery is OK then it is not changed, no gizmo reading to send down the line, no warranty claim!

Kingo

[Sagitar]

We stock the batteries, I have sold two this week!

On a warranty note we have a battery gizmo, it's plugged onto the battery, if it says it needs changing then it is changed, if it says battery is OK then it is not changed, no gizmo reading to send down the line, no warranty claim!

Kingo

Fine, but it doesn't explain why my dealer took three goes before finally saying that there was a defective cell and the Battery needed changing. Testing a Battery seems to depend upon the current state of charge, which by the time I got to the dealer was always good because I had been driving it. I suggested that they should keep it for 24 hours and test at the end of that time. They did, and then diagnosed a faulty cell and the Battery was changed under warranty.

[Parts-King]

I don't know, I'm not your dealer, the gizmo is supposed to check the state of the Battery regardless of you having just driven the car or not. A faulty cell should be diagnosable on the spot, and not have to leave it 24 hours

Kingo

[Grumpy Cabbie]

I don't know, I'm not your dealer, the gizmo is supposed to check the state of the battery regardless of you having just driven the car or not. A faulty cell should be diagnosable on the spot, and not have to leave it 24 hours

Kingo

Not having a pop at your Kingo but is the gizmo easy to use or does it have loads of settings that the untrained might get wrong? I only ask as there are numerous posts both on here and the US forum where Toyota dealers say the Prius 12v is fine yet clearly it isn't. Once the car is left for a while (usually overnight) the 12v loses its charge and the fault picked up. Is the gizmo 99% fool proof or are there loads of technicians out there using the wrong setting on the Prius an getting the wrong results? Do they have to select 'Prius' option or do they inadvertantly leave the car in 'Ready' mode and thus messing up the result or does it pick up on that?

[wass]

Sounds to me like the dealer didnt use the gizmo on the first 2 occasions but finally got around to it on the third occasion since those gizmos are normally a pass /fail thing rather than pass/maybe wait for a bit to see if it gets worse/fail thing.

[Sagitar]

I don't know, I'm not your dealer, the gizmo is supposed to check the state of the battery regardless of you having just driven the car or not. A faulty cell should be diagnosable on the spot, and not have to leave it 24 hours

Kingo

I am sure you are right and modern test equipment is very clever and intelligent. I'm afraid I don't know about gizmos and was simply using conventional wisdom based on experience. The conventional method of testing for a dead cell says, first make sure that the Battery is fully charged in order to establish a datum, then let it stand for at least 12 hours with no load connected, then test the specific gravity of each individual cell and look for differences. It's the only method I have ever used personally and I know it works, but clearly I should have asked more questions about how they did their checks.

Thanks for the information. I will know better next time.

[robbo40]

update; When I attended the garage the Service Manger assurred me that the correct oil was used in the vehicle and the incorrect (unknown) version entered on the work sheet. He had the Battery retested and it was apparantly showing good on his gizmo, however due to the problems I had encountered he said he was going to order a new Battery under warranty but it would take about 2 hours for delivery. I was able to wait for the vehicle. After the two hours the Battery was exchanged, the Senior Technician informed me that during this time he had checked the battery on several occasions and it was now showing a fail reading and he suspected a fail in one of the cells. No other problems as of today...hope no more either!!

[Sagitar]

He had the battery retested and it was apparantly showing good on his gizmo, however due to the problems I had encountered he said he was going to order a new battery under warranty but it would take about 2 hours for delivery. I was able to wait for the vehicle. After the two hours the battery was exchanged, the Senior Technician informed me that during this time he had checked the battery on several occasions and it was now showing a fail reading and he suspected a fail in one of the cells.

That is very similar to my experience. Does it not indicate that perhaps the "gizmo" is not so "state-of-charge-independent" as has been suggested?

[Grumpy Cabbie]

That is very similar to my experience. Does it not indicate that perhaps the "gizmo" is not so "state-of-charge-independent" as has been suggested?

lol Sounds like it to me - considering how often this issue is reported.

(Sounds like the gizmo is a load of pants considering it can't detect a shorted cell!)

[Peter Carter]

I have this fault, mine will not show the ready light at every start. I have a brand new Battery, I have checked the Battery voltage is 14.2 when switched on. The brake lights do come on and yet the ready light still does not come on. Anybody got any further ideas?

[YarisHybrid2016]

On 8/6/2018 at 11:21 AM, Peter Carter said:

I have this fault, mine will not show the ready light at every start. I have a brand new battery, I have checked the battery voltage is 14.2 when switched on. The brake lights do come on and yet the ready light still does not come on. Anybody got any further ideas?

Take it to a garage to be looked at.

[Rupsy flow]

Toyota alphard hybrid 2006, ready light comes on for a second and turns off..leaving the ignition on