Scary braking issue

[H1JFG]

My wife experienced a scary issue with the brakes on her NX300h F-Sport (2017). She was driving along the dual carriageway (A8 in Scotland) on Monday morning when the dashboard lit up like a Xmas tree. Multiple warning messages relating to ABS, pre-collision, etc. Tried to stop the car but had almost zero braking power. Pushing the brake pedal all the way to the floor (unusual in itself) resulted in only the slightest amount of braking power. Really scary situation given she was travelling at 60MPH in early morning rush hour traffic. She eventually managed to stop the car. Called Lexus Recovery (AA) who came out within the hour. They confirmed something very wrong with brakes. Again the brake pedal was going all the way to the floor and making a strange noise when pressed. AA declared the car undriveable and ordered up a recovery truck to take it to Lexus Edinburgh. (Note: The AA man checked brake fluid and pads/disks and said no issues. He actually reported the problem on his sheet as potential shattering of brake servo!)

Lexus Edinburgh put the diagnostic tool on the car which identified an error code for one of the rear ABS sensors. Apparently the way the sensor works (metal rotor spinning against a magnet) means that metal filings can break off and "clog" the sensor causing it to malfunction. So they took the sensor off, cleaned it out and then re-fitted it. Re-ran the diagnostics and no errors. And in their mind the problem was "probably" fixed and they would return the car. No assurances that it wouldn't happen again but if it did "they would take another look at it". So basically if the brakes fail at 70MPH on the motorway putting my wife in a very dangerous situation then they will do the decent thing and have another look. Unbelievable. They didn't bother to contact my wife to ask what had happened. Simply took the car off the recovery truck and ran their diagnostics and then followed the Lexus procedure which match the error code. Even when I rang them to explain what had actually happened they responded with "that couldn't possibly happen" and "a malfunctioning ABS sensor would not cause that to happen". So they were basically calling my wife and the AA man liars. I also pointed out to them that the (obvious) fact that the car had another three ABS sensors which had been on the car for exactly the same amount of miles (22,000) and as such there was a very high likelihood that they will have the exact same build-up of metal shavings, and therefore any one of them could be ready to fail. maybe in a day, a week or a month. And maybe the correct thing would have been to clean ALL of the sensors. But they weren't interested, Basically saying they wouldn't get reimbursed from Lexus for that work because those sensors were not showing as faulty. Again, unbelievable. And a complete lack of care towards the safety of one of your customers. 

I have no idea whether the malfunctioning ABS sensor was the issue. If it was, and it did cause a massive reduction in braking performance, then how can Lexus not class this as a huge safety issue. Losing 90-95% of braking performance without warning cannot be acceptable. Surely a malfunctioning sensor should just disable ABS. Why should it reduce braking performance. Where's the sense in that? Even cleaning out the sensor is a temporary fix as it will most likely happen again. Especially with four sensors. But more worrying is (if I believe the Head of Service at Lexus when he says the ABS sensor cannot cause this to happen) the possibility that it isn't the ABS sensor and the root cause of the issue is still there.

End result. My wife will not drive the car. And I can't really blame her. She travels to work and back every day along the M8 motorway so maybe 90% of her everyday journey is at 70MPH. If the issue happens again its likely it will be at that speed. This time she was lucky in that she had literally just come off the M8 onto the sliproad so less traffic. She wants rid of the car. Immediately. 

So, obvious question, has anyone ever experienced something like this themselves in their Lexus. 

[PCM]

Did the car accelerate at the same time?

I've known that happen.

[olliesgrandad]

Never had any issues with brakes on the 3 Lexus I've owned 2014 IS300h f sport 2015 GS300h and 2015 RX450h. 

Trouble is that all modern cars are so complex. Had a new 2014 Mini that would randomly do emergency braking at 70. Dealer never resolved the issue as it showed no fault codes because the computer had decided there was an emergency based on the camera system. 

[Steve Oliver]

I can't help thinking that you should be sending your words to Lexus Customer Services rather than just the dealership!

[royoftherovers]

1 hour ago, Steve Oliver said:

I can't help thinking that you should be sending your words to Lexus Customer Services rather than just the dealership!

Spot on Steve and I would inform HJ so that he can include it in his database of problems experienced by owners.

[H1JFG]

3 hours ago, PCM said:

Did the car accelerate at the same time?

I've known that happen.

No. Car didn't accelerate. 

[H1JFG]

33 minutes ago, Steve Oliver said:

I can't help thinking that you should be sending your words to Lexus Customer Services rather than just the dealership!

Issue is with dealership at the moment and they have said they will raise with Lexus UK on my behalf, but if I don't get a satisfactory response then yes, I will raise directly with Lexus Customer Services. What's the best process to do that? Do they have an email address? Phone number? Hotline?

[Tel]

I simply do not believe their diagnosis as the phenomena of filings causing the issue makes no sense whatsoever in the context of their Report.

 

One would assume such a presence would signify a fault & the unit would be replaced whilst the other 3 ABS units would be inspected to confirm your braking system is perfect.

Erasing a Fault code is secondary, evidence of metal particles in the Brake System is the Primary fault that every other Dealer would resolve themselves.

Tel

[Farqui]

Johnathan, reduced braking sounds very scary and I can appreciate why you both now have no confidence in the vehicle.

It's odd that an issue with the ABS/pre-collision system didn't still allow the actual brakes to slow the vehicle (rather than the hybrid motors), the brakes are one of the most important safety systems and should be tested above/beyond normal conditions.

I'm no expert but I would have thought a warning with the pre-collision system would have resulted in the dealership testing and re-calibrating the sensor.  I've read that these sensors can get confused if they're dirty, covered in snow or even wet. 

Does the vehicle have a grill mounted sensor for adaptive cruise control and emergency brake assist? 

Has the vehicle had any work done around the grill or maybe even had the tracking adjusted? 

I hope it doesn't happen again.

[GruffaloRider]

I could be wrong but... it sounds like it could be an issue with the brake servo or master cylinder. I have seen this problem with cars in my previous life as a mechanic. Far be it for me to question Lexus technicians, I haven't  touched a spanner in years and not up to speed with current technology. ABS sensor fault would just flag up an alarm without brake failure (red herring maybe).

[DanD]

I would also raise this with Lexus Head Office and bypass the dealer on the basis that you are not happy with their response. I would also suggest that, if you do not receive satisfactory assistance, you will contact the motoring press for advice. All motoring magazines have pages dedicated to customer complaints. Raising the issue with Lexus HQ via their Twitter page is a good way to kick them into action also.

With regards to the dealer, I would demand a thorough investigation and ask for a courtesy car whilst yours is being looked out. You could ask for a print out of all the tests they have carried out and asked for these to be reviewed by a qualified third party. 

If they are confident that the problem is fixed, they should not have any issue with one of their staff test driving the car for a few days: record the mileage before and after for evidence that the car was actually driven by them.

Is there another Lexus dealer in your area that you could take your car to for a second opinion?

[DanD]

I haven't got the time to review this in detail, but this looks like an interesting article that could be relevant to your problem as it also relates to Lexus models:

https://www.nbcnews.com/news/us-news/toyota-recall-1-7-million-vehicles-over-brake-problems-n226086

[Steve Oliver]

On 10/16/2019 at 9:48 AM, H1JFG said:

Issue is with dealership at the moment and they have said they will raise with Lexus UK on my behalf, but if I don't get a satisfactory response then yes, I will raise directly with Lexus Customer Services. What's the best process to do that? Do they have an email address? Phone number? Hotline?

Like Daniel suggested - I would probably tweet to them at @LexusUK and @lexus to get their attention - and ask them where to send your complaint. Their customer service number is 0345 129 5484. Or you can complete the form at https://www.lexus.co.uk/forms/customer-relations-contact-us.