Blinking Afs Light On Dashboard

Normski · November 27, 2010

Touch wood my Lexus RX has been faultless...until now. Was driving along today when all of a sudden the "AFS OFF" light started to flash. I stopped and restarted the car and all went back to normal but i'm now worried. Having done a couple of searches here it could be a leveling sensor problem. Anyone had this replaced - if so how much are we looking? I'm presuming it's not a DIY job??

I reckon all this could be related to some condensation i've been seeing in my passenger headlamp. Hasn't really bothered me until now but i've got a feeling it could be related :(

Anyway, any info guys would be much appreciated.

Ta.

carsparks · November 29, 2010

I think you'll find it is the adaptive front lighting system afs. Best get it plugged in to a diagnostic tool to read the data. It may be linked to your condensation problem in a headlight.

welland · February 9, 2019

Hi all,

I started getting this flashing AFS light on my 2006 rx400h today. I found that the position of the AFS switch made no difference after the flashing began, but if I parked and turned everything off, the problem must sometimes have reset, because it did not always come on again straight away. I've made several journeys in the dark this evening and found that when the light was not flashing, the headlights did turn sideways as normal when cornering. When the light was flashing, the beams did not turn sideways.

The dipped beam height did not seem to be affected all, though I have always felt that it was too low.

I see that some have said that the warning light means that the height sensor is faulty - or the linkage is broken. However, the handbook shows that there is a separate warning system to warn when the self levelling system is faulty, and this system has not been triggered.

I have not yet checked the height sensor as it's been dark outside, but I will have a look tomorrow, weather permitting.

Is the diagnosis of the height sensor definitive, or could it be anything else?

ColinBarber · February 10, 2019

Do the lights perform their dance when you first start the vehicle? You will get AFS warning if that self test doesn't complete properly so maybe one of the motors and/or position sensors isn't working correctly.

PCM · February 10, 2019

17 minutes ago, ColinBarber said:

Do the lights perform their dance when you first start the vehicle? You will get AFS warning if that self test doesn't complete properly so maybe one of the motors and/or position sensors isn't working correctly.

i.e., lights on first, then ignition on ...

welland · February 10, 2019

3 hours ago, ColinBarber said:

Do the lights perform their dance when you first start the vehicle? You will get AFS warning if that self test doesn't complete properly so maybe one of the motors and/or position sensors isn't working correctly.

Hi Colin, I think the warning light began flashing even before I turned the headlights on. My wife first noticed the flashing light in the daytime, when the headlights were not used.

Does this rule out the test you described as a possible source of fault?

welland · February 10, 2019

I got my head underneath the rear today to examine the headlight level sensor. It was in one piece, all joined together, and nothing appeared wrong. I unplugged the electrical connector anc found tthe connectors all shiney and bright. So, nothing appears untoward with the sensor or its linkage.

Herbie · February 10, 2019

1 hour ago, welland said:

I unplugged the electrical connector anc found tthe connectors all shiney and bright. So, nothing appears untoward with the sensor

Did you only look at the plug/socket? It could be the inner workings of the sensor (springs and contacts) so you really need to take the cover off and check continuity and/or resistance with a multimeter before you can rule the sensor out.

welland · February 11, 2019

32 minutes ago, Herbie said:

Did you only look at the plug/socket? It could be the inner workings of the sensor (springs and contacts) so you really need to take the cover off and check continuity and/or resistance with a multimeter before you can rule the sensor out.

Hi Herbie,

yes I did just give the plug and socket a visual inspection.

If there is a fault inside the sensor, wouldn't it be strange that the AFS warning would be triggered instead of the headlamp leveller warning?

welland · February 11, 2019

14 hours ago, PCM said:

i.e., lights on first, then ignition on ...

Sorry, didn't spot your comment yesterday. Is this a question? I did the following test this morning

1) turn key to position 2.

2) after a pause of maybe 10 seconds, the afs light began flashing.

3) turn key to position 3 to put car into "ready" state.

4) wife turned headlights on while I observed them outside. I don't think they did their usual dance.

I suppose a key question is this:

Is the lack of the dance a symptom or cause of the flashing afs light?

welland · February 11, 2019

Just found this good video on YouTube:

However, my linkage is all attached and both my ball joints are swiveling freely. Anyway, I'm a bit confused about one thing in the adjuster. It has three nuts on the threaded bar. Clearly, the centre one must be fixed in order to turn the threaded bar. I would have expected the nuts at the ends to move freely and that they would be tightened against the ball joint as a locknut. The video did not mention this locking function of these nuts. Are they supposed to move freely?

PCM · February 11, 2019

"my linkage is all attached and both my ball joints are swiveling freely."

!

The-Acre · February 11, 2019

1 hour ago, PCM said:

"my linkage is all attached and both my ball joints are swiveling freely."

!

Just like Elvis Presley! 🎵

ColinBarber · February 11, 2019

The dance happens when the ignition is turned on. I don't think the headlights need to be turned on. Turn on the lights and then turn on the ignition to see it happening (or leave on auto and test at night).

The system will check the height sensors (both front and rear) and move the lights. If something doesn't work correctly you will get a warning light. There will also be a fault code stored in the ECU - that will help determine what the issue is.

welland · February 11, 2019

1 hour ago, ColinBarber said:

The dance happens when the ignition is turned on. I don't think the headlights need to be turned on. Turn on the lights and then turn on the ignition to see it happening (or leave on auto and test at night).

The system will check the height sensors (both front and rear) and move the lights. If something doesn't work correctly you will get a warning light. There will also be a fault code stored in the ECU - that will help determine what the issue is.

Hi Colin, thanks for this.

I have just popped out into the car to retest it. Brrrrr. 2C on the thermometer, but frost already forming on the windscreen.

1)Before I put the key In the ignition lock, I turned on the lights. They came on without the dance.

2) I then switched it one click further to auto, the lights went off.

3) I turned the key to position 2 and the lights came on again, without the dance. Bizarrely, the flashing AFS warning did not occur, even after waiting around 2 mins.

4) I switched the lights off and on a few times, but never saw the dance or the flashing AFS light.

Is it true that the dance only occurs once in each drive cycle?

I will try to plug in my laptop tomorrow evening to check for DTCs.

ColinBarber · February 12, 2019

21 hours ago, welland said:

Is it true that the dance only occurs once in each drive cycle?

Yes I believe so, either with ignition or when 'Ready' - cannot remember which.

welland · February 14, 2019

Just popped out with my laptop to check for DTCs.

OBDAutodoctor reported no faults at all.

EasyOBD11 reported a pending fault C0700: fault definition not available or manufacturer specific.

Baffled about why OBD autodoctor didn't report this fault too - maybe a false positive in EasyOBD11?

Anyway, checked google and somebody else reported this code means LF Solenoid Circuit Malfunction. Anybody know what this means? Could it be related to my AFS issue?

Meanwhile, the AFS light is not flashing now, but also the headlights do not dance when turned on.

Hmmmm (scratches head).

Rutlandlex · February 14, 2019

99% of the time when people get the AFS off flashing light it is the mechanical bit of the rear suspension level sensor that has snapped so I think that you are in the 1% Welland!

The fact that the fault is temperamental suggests an electrical issue rather than a mechanical one so it could be a component of the AFS that is a bit dodgy rather than headlamp levelling. That LF Solenoid problem would be Left Front but from Googling that error code and description most seem to suggest it's an ABS issue. I see no reason for AFS and ABS to be linked because they don't share any common parts that I know of.

That code could be a red herring that is either completely false or you could have an ABS issue in the pipeline. I think that what you're best to do is plug in your OBD readers when the fault is live and see if any new codes come up. These free systems can't connect to every circuit in the car unfortunately otherwise garages wouldn't spend 10's of thousands on diagnostic equipment if they could just use a laptop and free software would they?

welland · February 15, 2019

My wife usually drives our rx, but I stole it off her today- all in the name of research! 🤣. It's 15 miles to work, and most of it is on country a and b roads, so plenty of time to collect data.

So, still no more flashing AFS light. It has not flashed for several days.

Headlights still do not dance on start-up. Think the last time this behaviour occurred was last weekend.

Still no DTCs in obdautodoctor, and c0700 pending in easyobd11.

Whilst driving home in the dark, the right hand headlamp was clearly moving left and right a lot, corresponding to steering input. The left hand headlamp did move left and right as well, but it's movements were much more subtle and of smaller magnitude.

Is it normal that the left hand headlamp moves less than the right hand one? The sideways movement does not normally occur when stationary. Is there a known test mode to test the movement?

Is it normal that the start-up dance does not occur at every start-up? Is there a known test procedure to force a dance to occur?

PCM · February 16, 2019

If I have the lights on first, then ignition, it always does the 'dance'.

welland · February 16, 2019

Been doing some wider reading. I'm convinced that my dipped beams are both too low. But I have no idea whether I need to make an adjustment at the headlight or at the self levelling sensor.

I made an observation last weekend that may be relevant, and which I've not shared yet. After a journey in the dark in which the afs light was flashing, i parked with the headlights on and noticed that the dipped beams were not stationary. They seemed to be flicking up and down a little, whilst there was absolutely no movement in the vehicle. Thus movement that I observed was definitely not the same as the usual start-up dance.

Herbie · February 16, 2019

2 hours ago, welland said:

They seemed to be flicking up and down a little, whilst there was absolutely no movement in the vehicle.

The sensor is just a variable resistor so I'd say the internal connections need cleaning. You need to get it off the car and on the bench, clean everything up inside and measure the resistances against the manual. Think of a radio with a crackly volume control. Cleaning the wiper and the carbon track stops the crackling and this sensor works on the same principal.

welland · February 17, 2019

Spend a few hours underneath yesterday and will share observations and progress:

When the height level sensor is unplugged, the afs light flashes. Though I forgot to plug in my laptop at the same time to see if it reported any DTCs. Was really surprised that the dash display did not show the levelling fault.
Initial observations of the rusty linkage bolts made me think that it would be impossible to remove thrm without shearing them off. In the end I managed to successfully remove the two which held the sensor bracket. However, unfortunately the bolt on the bottom ball joint sheared when the nut was half way off. Luckily, there was just enough remaining to get 3/4 of a nut on it! Phew.
Having got the sensor off, I discovered that one of the coil spring connectors was badly rusted. And one of the fragile sliding contacts turned to dust when I looked at it. I tried to clean the rusty spring and rebend the other copper contact to make a connection, but the resistance values were all over the place when l had finished. New sensor is required.
Having put it all back together, the headlights are still too low (predictably), the afs light does not flash and the lights don't dance on start-up.

I'm hopeful that replacing the sensor will fix the height of the beams, but we'll have to see what that does to the startup dance.

There seems to be plenty of choice on eBay around £25 for replacement sensors in the UK ( Chinese and Hong Kong stock is half the price, but takes a while to arrive). Does anybody have any experience of these after market sensors - are any worse quality than any of the others?

welland · February 18, 2019

Ive ordered one of these today: https://www.ebay.co.uk/itm/152859408291, should be here in a couple of days.

Meanwhile, I tried the lights again today and still no startup dance, but the headlamp beam was higher, then lower, then higher..... Seems like the height adjustment system is working, but is getting fluctuating messages from the old sensor.