geraintthomas

HELP! Parking Sensor & BLIS fault

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Hello!

I've just bought a Mk3 Focus Titanium today that's literally packed full of options. The garage has been brilliant, and has put a three month warranty on it that covers everything.

When I got in the car in the dealership, the car battery was flat. A quick jump start got the car running, but was instantly plagued with errors - presumably because of the flat battery. A few mins later, they all went and the car has since been driving lovely. Except for two things - parking sensors and the BLIS system.

Parking sensors - the Park Pilot enables in reverse, but the sensors don't pick up anything. The radar is empty on the screen.

BLIS - they work, for about 10-15 minutes, then both the left and right sensors throw a fault at the same time. Restarting the car fixes the issue, only for another 10-15 minutes.

The garage has said they'll take the car back to repair it, but I've offered to try and fix it first as it's a faff taking it back to the garage and to be without a car for however long it takes. Plus I'm very good at car mechanics and maintenance, so I'm all up for attempting to fix it, for as long as I'm not out of pocket.

The two things that I know:

1. The battery was dead and threw up codes when I bought the car today, and the parking sensors and BLIS are now mulfunctioning. Coincidental?

2. Both parking sensors and radars for the BLIS system are both in the rear bumper. Are these connected?

Or they could be completely separate problems.

Anyone have any ideas on what I could do or what could cause this? I've reset the battery monitoring system, but no luck.

Thank you!

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UPDATE: The right hand side of the boot liner is wet.

It could be a water damaged parking sensor module, but how can both BLIS sensors throw a fault at the same time?

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Oh dear...the infamous Mk3 boot leak! 

You'll have to remove the bumper to reseal the vents so can check the sensors and wiring while you're there.

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20 minutes ago, TomsFocus said:

Oh dear...the infamous Mk3 boot leak! 

You'll have to remove the bumper to reseal the vents so can check the sensors and wiring while you're there.

Just had a look at that thread, and I'm quite thankful that it's a straightforward fix! I'll do that this week to sort the leak out.

Unfortunately though, it still leaves the parking sensor and BLIS problems.

Has anyone had this before? Where the parking system enables but no info comes from the sensors? And both left and right BLIS sensors throw a fault at the same time?

I'm guessing it's water damage, but I'm hoping it's nothing to do with it.

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Check around the boot fuse panel, could be water getting in there?

Sent from my SM-G965F using Tapatalk

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14 minutes ago, Stoney871 said:

Check around the boot fuse panel, could be water getting in there?

Sent from my SM-G965F using Tapatalk
 

There's water getting in by the vents, the leak isn't my issue really, it's why the park assist doesn't beep and why the BLIS malfunctions after 10 mins of driving. So strange.

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11 hours ago, geraintthomas said:

There's water getting in by the vents, the leak isn't my issue really, it's why the park assist doesn't beep and why the BLIS malfunctions after 10 mins of driving. So strange.

It seems like too much of a coincidence that you've got a wet boot and something faulty right next to it...  The rear sensor mulitplug could even have water running over it and be corroded by now.  That's definitely what I'd be checking first.

Bad batteries cause far more problems than this usually.  Faulty stop start, faulty hill start assist, power steering issues etc.  If it's the original battery, they come with a magic eye on top, could be worth checking that's still green.

Worth saying I had a lot of weird electrical issues when I first got my Mk3.  The battery was ok but it had been standing for a while unused.  A lot of the issues sorted themselves out over time & use without any repairs needed though!

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36 minutes ago, TomsFocus said:

It seems like too much of a coincidence that you've got a wet boot and something faulty right next to it...  The rear sensor mulitplug could even have water running over it and be corroded by now.  That's definitely what I'd be checking first.

Bad batteries cause far more problems than this usually.  Faulty stop start, faulty hill start assist, power steering issues etc.  If it's the original battery, they come with a magic eye on top, could be worth checking that's still green.

Worth saying I had a lot of weird electrical issues when I first got my Mk3.  The battery was ok but it had been standing for a while unused.  A lot of the issues sorted themselves out over time & use without any repairs needed though!

Very interesting to hear that!

My other car has a relatively new battery, so would it be worth swapping the battery temporarily and resetting the BMS, just to see? I'm hoping these issues iron themselves out but I'll phone the garage today to let them know what's happening to ensure that they fix the issue if it doesn't fix itself in a few weeks.

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2 minutes ago, geraintthomas said:

Very interesting to hear that!

My other car has a relatively new battery, so would it be worth swapping the battery temporarily and resetting the BMS, just to see? I'm hoping these issues iron themselves out but I'll phone the garage today to let them know what's happening to ensure that they fix the issue if it doesn't fix itself in a few weeks.

I'd just leave it and drive it for another week or so personally, swapping the battery just introduces another loss of power to the modules which is probably what causes the issues in the first place. 

If you do decide to swap, make sure the battery on your other car is suitable, needs to be an EFB battery.

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1 hour ago, TomsFocus said:

I'd just leave it and drive it for another week or so personally, swapping the battery just introduces another loss of power to the modules which is probably what causes the issues in the first place. 

If you do decide to swap, make sure the battery on your other car is suitable, needs to be an EFB battery.

Thanks for the help, I really appreciate it.

I called the garage who were very understanding, and said if it doesn't go away after a few weeks to just bring it back to them. 
 

An EFB battery... not actually heard of one of those! Any way that I can check?

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28 minutes ago, geraintthomas said:

Thanks for the help, I really appreciate it.

I called the garage who were very understanding, and said if it doesn't go away after a few weeks to just bring it back to them. 
 

An EFB battery... not actually heard of one of those! Any way that I can check?

EFB stands for Enhanced Flooded battery, they're designed for use with stop/start.  EFB should be clearly written on the battery if it is one, shown here next to the Ah rating.

Heavy duty genuine ford diesel battery fully working | in Bradford ...

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Thanks.

I've just checked it and that eye on the battery is black. Also it's reading as 11.4v. When I've run the car for a while and stop it, it reads as 12.5v, but then slowly drops when the engine is off again.

Could this be the cause to everything?

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19 minutes ago, geraintthomas said:

Thanks.

I've just checked it and that eye on the battery is black. Also it's reading as 11.4v. When I've run the car for a while and stop it, it reads as 12.5v, but then slowly drops when the engine is off again.

Could this be the cause to everything?

Ok, it does sound like you need a new battery then.  Hopefully the dealer will cover the cost, even if you change it yourself to save the drive back there.

I'm still not convinced that's the cause of your parking sensor issues but I wouldn't rule it out! :smile: 

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I'll give them a shout for definite.

I'll the bumper off to have a look at the wiring for the sensors when the weather clears. The module could also be water damaged, so I can always pick up a pre-owned module to see if it works. Luckily they're cheap.

Hopefully the battery will sort the BLIS out (and also the Stop/start as that doesn't work either) and a replacement module for the parking sensors.

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So I was at EuroCarParts and they're asking £380 for an EFB battery?! Jesus Christ I didn't know they were that expensive. I didn't buy it, but asked the guy to test mine... to which he said he can't unless it's disconnected from the car. Useless.

Whilst I was there, I reset the BMS properly (3x fog light 5x hazard) and it hasn't thrown an error on the drive home, which was about 20 minutes or so. 

Now it could be that it needed resetting after the car was left dead for however long at the dealership, or it could be a coincidence and it'll appear again. Either way it does sound battery related.

Any cheaper websites that you'd recommend sourcing an EFB battery from?

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They are expensive, but that's just the artificially inflated price.  If buying from ECP you should always use click and collect to make use of voucher codes.  Currently SALE60 for 40% off batteries.

It's been years since I've bought a battery myself so not sure of the cheapest sites now I'm afraid.  It might even be worth an ask at your local Ford dealer though.

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4 hours ago, geraintthomas said:

Any cheaper websites that you'd recommend sourcing an EFB battery from?

Tayna is a good website. You don't say what your engine is, so you'll have to look it up yourself. You can do it by your Reg. No. Just double-check the size against your current battery:

https://www.tayna.co.uk/car-batteries/

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On 6/29/2020 at 7:16 PM, geraintthomas said:

The garage has been brilliant, and has put a three month warranty on it that covers everything.

Consumer Rights Act 2015 - Up to 6 months following purchase it is up to the dealer to prove that any fault occurring did not exist at the time of purchase. This trumps any warranty.

IMO - if i'd bought a car and the battery went in the first 6 months, the dealer would be replacing at entirely their cost (as well as fixing the parking sensors/blis).

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True.

I've purchased a multimeter rather than keep borrowing the neighbours. My other cars are 12.8v and 12.6v. I tried the focus this morning and it was a whopping 11.8v.

This makes sense. Yesterday when I drove the car, it took a while for the BLIS fault to appear because the charge raised slightly (but only up to around 12.1v to 12.2v)This morning though, and all of today, the fault appears as soon as I start the engine as the battery is seriously low at 11.8v.

If what I've read online about modern car electronics being sensitive to battery levels and critically relying on a good battery, then this should fix the issue.

Hopefully it'll fix the parking sensor issue too, but that may be separate.

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On 6/29/2020 at 7:16 PM, geraintthomas said:

When I got in the car in the dealership, the car battery was flat. A quick jump start got the car running

I would have been very suspicious of that and I would have made fitting a new battery a condition of buying the car. Batteries get badly sulphated if allowed to go flat and don't really recover full capacity. The chances are that's the original battery and 9 years old so time for a new one anyway.

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I totally agree with what everyone's saying. I suppose it could be suspicious, but I put it down to being sat on the forecourt during covid. Nevertheless, it shouldn't have been flat, but hey ho.

So the way I'm looking at it is that I don't know if the issue is big or small with the parking sensors or BLIS system, and I need to be on good terms with him if it's a big problem for them not to start being funny with the repairs. If it's just the battery and it fixes it, then I'll ask him to cover it, which he kindly said he would. If the battery doesn't fix it (it needs one anyway), then I'm going to say to him that I'll cover the cost of the battery (to show I'm being super reasonable here) but he needs to take the car in to get it looked at.

He's been great so far and said if anything is wrong with it to just bring it back. He's offered an auto electrician to look at it if I can't fix it and genuinely has been very good about it all. I know some of you may think "Just get him to cover the battery too, it's your right" and, whilst I agree that's technically the right thing to do, I want to be careful. If the car has more than a bad battery, I want to be as reasonable as possible so that he won't start being annoyed, cutting corners with fixing the car, and that's a road I don't want to risk. If I'm reasonable and being shown to fix the car as much as I can, he'll be much more inclined to spend the time and money on it if needs be.

I'm happy to cover the battery if it needs more repairs, but if it does fix it, I'm sure he'll be happy that he doesn't have to pay an auto electrician to diagnose the bad battery, and would happily cover the battery cost.

I just want the car to work and for us to work together to get it to that stage. He's very much up for repairing the car and is on very good terms with me, so I'd like to keep it like that, even if that costs me a battery, I'm happy to help.

The battery is coming later, so I'll let you guys know!

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Update! BLIS is fixed!

I've fitted the new battery. The stop/start now works a charm, but the BLIS faults continued. However, I ordered a diagnostic tool that scans for every module on the car, not just engine fault codes. When the faults appear, if you restart the car they go away, until 10 mins of driving later.

Earlier on I started the car with no BLIS faults, like usual, but then I scanned the modules with the diagnostic kit. It picked up a huge list of errors, some of which were things which worked fine. On the list were the BLIS modules. I assume all of these were from the dead battery when they jump started it, as the car threw a load of errors at me before settling down. I cleared the codes on all of the moudles, they all passed the re-scan, and the BLIS modules haven't failed since. They've been working an absolute charm on two long drives now.

So there we go, it was a bad battery. Fitting a new battery and clearing the codes fixed the issue.

However, my parking sensors still don't work.

I took the parking aid module out of the car and... it had water on it. The infamous boot leak has happened on my car, which I'm not worried about as it's easily fixed. Unplugging the module and starting the car causes the car to throw a parking aid failure error, and plugging it back in makes the car think the sensors are fine, but they don't pick up anything.

It's most likely a water damaged module. I'm going to disconnect all 4 sensors tomorrow, give the contacts a good clean, then re-connect. I've checked inside the module casing and it's completely dry, so if it is water damaged I'm too late.

I spoke to the dealer on the phone and he's booked me in for Saturday 2pm for an autoelectrician to look at the car for me, so all is well. I genuinelly think a replacement parking aid module will sort it though, considering it's next to the boot leak and actually had water on it.

I'll keep you guys updated. Sorry for the long posts!

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...and now my parking sensors are working. By themselves.

I took the module out and dried it out, so it may have been that or it may have been the new battery. Either way they work! I'll sort that leak out now.

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