Flat 12V battery on 2007 hatchback: do I have the right plan?

Hi everyone. I'm a bit shaken.

Someone came to replace the 12V battery, but they're now saying that there's a fault with the hybrid battery that they don't have the expertise to fix. They're telling me I should sell the car for a percentage of what I paid for it.

Perhaps it is right that I have wrecked this car by not driving it.

These are the error codes: P0A1D and P0AFA. The mechanic kept talking at me as I was trying to look them up, so I can see that there appear to be people here who've fixed similar problems themselves. I kind of need to vent right now so I'm putting this down here to focus my thoughts a bit.

I don't know if I should seek a second opinion or not. This guy said the previous 12V battery had been installed incorrectly, but I couldn't make sense of what he was saying about why that would be. He was a bit of a fast talker, and his overall manner made me think I should really get a second opinion before doing anything. At the same time, the hybrid battery is indeed low when I try to start the car. I have every reason to be in denial that I've wrecked the car by not driving it, but I feel like I should do some investigation before accepting that as fact.

I find this car in November, get it inspected (by the same company that just changed the battery) and they found everything in good order and said in their opinion, it would last me a long time. Toyota looked at it in December and said everything was fine. The roadside assistance who jumpstarted me two weeks ago, said everything was fine except the 12V battery.

I've gone from everything appearing to be fine except the 12V battery discharging for readily explainable reasons, to everything being wrong.

Immediately before getting this car, I was mis-sold a car by a dealer who falsified the car's history. I walked through the process with a knowledgeable friend, who thought I had done everything right. I had this car inspected before buying it, as I said. Today's mechanic told me to get a "cheap little runaround", but that's exactly what I looked for when I was looking to replace the car I got mis-sold. The price of used cars had gone up so much that there were no automatic petrol cars cheaper than this one. Supposing I found one, I could get it inspected before I bought it, but given that I may have unwittingly wrecked this car, what would an inspection matter? There seems to be no right move I can make here.

Aargh

I'm going to have a search on those error codes. I won't be able to do the work myself, and I'm not sure how to find a reliable motor electrician to do it, and Toyota will demand my kidneys in part exchange. Scream

 

Update: friend advised me to call up the AA specialist Toyota roadside assistance. (You have to join, obviously, and pay a callout fee.)

They came over within an hour or so. Reported the following:
- the mechanic put the wrong 12V battery in (not surprised)
- seems too coincidental that this would happen right after changing the 12V battery, but he can't tell at this point
- he will also send me the details of the correct 12V battery, which, once I get more information, I will contact the company that sent the mechanic today and get them to supply that and replace the wrong one

The hybrid battery was low, but he was confident at first that that was just a voltage freakout after the change in 12V battery.

However, he found that he couldn't charge the hybrid battery past 57.5%, and the brakes are dodgy as a result, so he wouldn't recommend that I drive it.

SCREAM

He will recommend two electrical specialists I should consult before doing anything else. I will talk to them in the morning.

 

You may be right, sam spade 2. I hope not.

A hybrid car specialist, recommended by the AA technician yesterday, has taken the car and, rightly or not, agrees with the AA guy's assessment, that the vent pipe will not fit in the 12V battery that was put in yesterday. They tell me they've charged the hybrid battery up to 70% so far and the only code now is P3000. They will leave it charging overnight and get back to me in the morning.

They're also going to change the latch on the back door, which was sticking, and which I had a replacement part for after reading the threads posted here on the subject. I hadn't gotten around to ordering some replacement trim, but they said they already had some and will do that to.

Hopefully these people live up to their reputation and won't turn out to be just another source of bad advice.

 

Thanks drone13, the hybrid specialist may have mentioned parasitic loss, but I didn't have a hand free to transcribe everything he said, and some of what he did say escaped me, as I'm not an electrical or mechanical engineer.

I will make a point of asking about parasitic loss tomorrow when I talk to them, as well as asking for any subcodes.

 

Okay, they tell me it's corrosion. Pins snapped off in the sockets of the connector to the ECU box. The treatment is replacement of the ECU box and wiring loom.

 

So... I have to face the possibility I may be about to get ripped off. I'm not saying I am going to get ripped off, only taking the contradictions out and setting them on the table. Whether or not they mean anything.

Firstly, the hybrid specialist charges more for card payments vs. bank transfer or cash. This has been illegal in the UK since 2018, I believe. I offered to pay a deposit by card and he said no.

He also said the 12v battery is wrong, that it's for a Honda Jazz. And therefore needs to be replaced. According to what seems to be universal opinion on this forum, there's no such thing as a 12v battery that's wrong for a Prius. The total cost for that part of the work will be £150.

Over the video call this morning he showed me standing water that had pooled in a corner of the inside of the car near the ECU box. The water was very clean and clear. I am admittedly not sure if it rained overnight. But I remember I didn't see any standing water in the wheel well and neither mechanic mentioned finding any e.g. under the 12v battery on Tuesday.

From what I can tell, he seems to be marking up the (used) parts for the rest of it, but that's his prerogative, so I'm not too perturbed by that. (In terms of trusting him, I mean. In terms of paying for it, ouch).

I will say that the diagnosis seems to be consistent with the initial error codes, which I saw with my own eyes (but which the AA guy subsequently said might have been more transient than meaningful in the specific), and that this story here My battery replacement journey | PriusChat has some similarities with mine.

Given the balance of constraints in my situation, I don't perceive any real option other than to go along with this. It's more an intellectual exercise in curiosity, a game if you will... an expensive one.

Perhaps the tragic end to my story, whatever its specifics turn out to be, will serve some purpose as a warning to others.

 

Now the guy is asking me how long I've had the car, because it's clean and a lot of his customers are asking if it's for sale.

What if I took the hint and offloaded it?

 

Further thoughts:

If there is corrosion now, and around the battery (he sent me a picture saying he was going to clean it) I wonder why the inspection didn't pick up on that. Is it because corrosion isn't visible without unplugging the connectors? Or is it because some corrosion is to be expected?

Another question as to why he would be showing me a picture of standing water inside the car, as an explanation for the corrosion, on Thursday when there wasn't any on Tuesday. If this car lets in water like that, why isn't there any rust anywhere on it or in it?

 

So from what you say, @drone13 the connectors would have to be undone for the corrosion to be visible. They brought back the car this afternoon, so it's too late for me to do that kind of inspection.

The shop sent me pictures that clearly showed corrosion in the connectors and on the hybrid battery bolts. I will post them if anyone here thinks they will be helpful, but right now I don't want to fiddle around transferring the pictures from phone to laptop. What I can tell you is that the male connector pins in the pictures were silty with an accent of green, and some of them had snapped off into the female connector pins.

They brought back the car this afternoon and handed me the keys. They left the dead wiring loom and ECU box in the trunk for me, so if anyone REALLY REALLY wants to see them I can go and take some pictures, though it'll have to wait until tomorrow. They also sent me pictures of hybrid battery bolts with silty corrosion all around them, which they undertook to clean for me. I'll have a dig around and look for any grossly observable issues next time I open the trunk.

It is always possible for a repair shop to show you pictures of someone else's car or components and convince you it's yours (which is what I think happened when I got defrauded by that other dealer). They could even have given me back dead components that they had lying around in the shop. Since I didn't see the damage with my own eyes BEFORE they did the repair, I can't be absolutely certain that the repair shop isn't run by Fraudy McFrauderson.

However, at a certain point you have to trust someone. The bank called me up to question the payment I made, and make sure I hadn't been the victim of push payment fraud (where you are in contact with a genuine trader you're about to pay, and a third party gets in the middle and impersonates them to trick you into paying them instead). They said they had no particular reason to be suspicious of this particular retailer, it was just the nature and size of the transaction that got it flagged. However, seeing that the repairman drove the car to me himself in person and handed me the keys, and that he looked and sounded like the exact same guy I'd been FaceTiming, and that the bank details on the invoice he handed me were a match for the ones messaged to me over the phone number I used to contact that repair shop in the first place - if they were really someone else impersonating the repair shop, their dedication is impressive. Deep method. There comes a point where suspicion is not really productive, and you just have to accept some risk and be prepared to deal with it if things go against you.

Anyway - both the repair shop staff told me what an excellent and desirable car it is, how low-mileage and clean, and how beautifully it drives, and how many of their customers had expressed interest in buying it. If it doesn't throw any more problems for a decent while, great. If it does, then depending on the nature of the problems I'll consider selling it (though not to that repair shop, obviously). I do a mix of urban and highway driving, so the fuel efficiency isn't looking dramatically better than a petrol-only car with that journey pattern, even though I aesthetically strongly prefer a hybrid. It's disappointing, but them's the trade-offs.

 

And to answer your question @drone13 about why I didn't go to the shop and look for myself - it's 20 miles away, and I didn't have access to a car.