Easy Hill Start v Auto brake hold

[trout]

Just recently my auto hold warning light is not showing on the dash display.
It’s been fine up to now, first noticed during really cold weather, it took a drive of several miles before it illuminated?
This morning which was a mild day it was showing fine when I set off but on my return it had disappeared again, I’ve just restarted the car after a few hours in the drive, still no auto hold sign, I switched the engine off and restarted, now it’s showing again and working fine, ie it goes green when I apply the foot brake pedal.
It’s really hit and miss lately sometimes there sometimes not, anyone else ever experience this?
S.

[trout]

Steve...I checked the white and green LED behaviour today on a shopping trip. Auto Hold is operating on demand continually and is dependant on length of brake pedal depression when stopped. Halted for a couple of seconds and Auto Hold indicator goes green and continually holds...none of the 2 secs business. Lift off I am sure is smoother than Parking as well.

Many stops on flat-ish roads and it holds perfect...the 3 degree incline bit I actually wonder about. How could that be accurately sensed anyway?

Further to my problem with the auto hold the white display light was not present this morning again, I drove five miles and stopped, turned the engine off and restarted five mins later, still no light.
I should add that the orange light on the auto hold switch is on and illuminated, just no symbol saying auto hold in the dash binnacle.
As I pulled away I was on a slight incline, I applied the foot brake pedal as I needed to reverse, for the first time ever the hill assist lit up in green in the right binnacle display, it held for approx two seconds as you mentioned.
I have never seen this light before and I bought the car last July.
The auto hold has performed perfectly until now, I’ll mention it at service time as it’s a long trip just for that, it may even rectify itself before then.
Incidentally after I had reversed using the hill assist, I put the car into first gear and the auto hold reappeared in the display again??? It remained on for the rest of my journey.
So I’m really posting this to confirm that the facelift QQs J11b do have both functions fitted.
S.

[calnorth]

it held for approx two seconds as you mentioned.

I put the car into first gear and the auto hold reappeared in the display again??? It remained on for the rest of my journey.

In response:
Auto Hold on stop is permanently held on until I drive off on both flat-ish surfaces and inclines. The Parking brake over rides Auto Hold I note

Auto Hold green lamp indicates that at least all brakes are on or at least the rear two are. From what you say the system is sensing incorrectly.

The QQ braking control uses a complicated adaption of the ABS system. The braking system is safety critical but in the case of Auto Hold can be turned off by the driver. I'm surprised that a System Fault is not being displayed?

Cheers

Colin

[trout]

it held for approx two seconds as you mentioned.

I put the car into first gear and the auto hold reappeared in the display again??? It remained on for the rest of my journey.

In response:
Auto Hold on stop is permanently held on until I drive off on both flat-ish surfaces and inclines. The Parking brake over rides Auto Hold I note

Auto Hold green lamp indicates that at least all brakes are on or at least the rear two are. From what you say the system is sensing incorrectly.

The QQ braking control uses a complicated adaption of the ABS system. The braking system is safety critical but in the case of Auto Hold can be turned off by the driver. I'm surprised that a System Fault is not being displayed?

Cheers

Colin

Hi Colin, no system fault indication on dash, performed fine today, white auto hold light came on and remained on.
Fingers crossed it behaves itself, it’s an extremely useful function that you take for granted until it stops working.
S.

[DaveBerlin]

Colin / Steve, I did not want to jump in on this but does this Nissan explanation help - Dave

[trout]

Thanks Dave, but I’m aware off all that, my problem is the none appearance of the Auto Hold light in the left binnacle.
When it is there it turns green and works fine.
It seems to be an intermittent fault which is the worst, the day you take it to your dealer you can bet your bottom dollar it’ll be working fine!!!
S.

[DaveBerlin]

Steve, OK so it did not help Have you tried logging, photographing these intermittent faults at least then you have something to show you Dealer or NCS - Dave

[calnorth]

The system related to this problem is likely the Brake Control System (BRS) . In the N. American US Nissan BRS repair document a function is shown as HILL START ASSIST FUNCTION. This is not in the UK QQ (J11) I have. AUTO HOLD is present and as far as I'm concerned does not behave quite the same as the HILL START.

I have had a good search on the web for the UK QQ repair documents and the set of them (50 odd) are not there. So its a misleading situation. I prefer to inform a dealer/mech if necessary and being well informed myself...not going to happen. Anyway, this is the ABS system.

The US document does define a procedure which is a physical ABS warning light check and then to perform ABS self diagnostics with their NISSAN CONSULT computer. It scans for any of about 50 errors flagged and none are labled Hill Start or Auto Hold. However, there are about 5 electronic processor/modules associated with ABS and anyone of those may flag error(s) (DTC) related. So the Auto Hold events/fails should be flagged and recorded via one or more of the modules..... I'd expect?

[StevieG]

Hi all, thanks for the inputs . I have been off line for a bit. :
Trout your confirmation that both systems are fitted is appreciated although I have never seen the Hill assist light illuminate. I am still at a loss to see what Hill assist brings to the party that auto hold does not already supply. For now I shall continue to rely on and use the auto hold function unless it decides to go missing as per your own experience!
Colin I still like your thoughts that auto hold selection disables hill assist as it would explain a lot. Dave thanks for your good description of both from Nissan. Reading both again brings me back to my original reason for asking Why? And what the difference?

Thanks again for all your thoughts.
Steve

[trout]

Steve, I don’t think you’ll ever see the hill assist as long as your auto hold is present, it’s the first time in nine months of owning my QQ that I’ve seen it.
Perhaps if you park on a slight hill and disable your auto hold the hill start may show?
It’s a green symbol of a car on a hill in the right binnacle.
S.