Afs Off Lights Flashing

[scottmcc]

Hello all

I am on a business trip hundreds of miles away from my home and MANUALS.. It has been raining alot while I have been traveling and now my AFS OFF light is flashing. Continues to flash for many minutes and then quits.. My headlights seem to be lower (top cutoff line) than normal.. Do the manuals say anything about the Flashing AFS OFF indicator. Is this a auto height leveling problem? I thought maybe that my lights were dirty from the excessive rain so I cleaned them and now it seems like the AFS OFF light does not flash as long but I am not sure.. Just hoping maybe.. Still the lights are adjusted low..

PS.. AFS OFF light continues to flash even if I turn on the AFS OFF switch.. Once the flashing stops and I press the switch the light will come on normally..

Thanks

PSS.. could not do a search of the forum for this as the AFS does not meet the four character minimum requirement.. Can we change that?

[scottmcc]

Finally made it home...Turns out the right rear LH height control subassy burned up. causing the AFS OFF light to flash.. All charred on the inside.. Looks just like a potentiometer with an O ring around it.. Part is around $300...not under warranty..

[wwest]

Finally made it home...Turns out the right rear LH height control subassy burned up. causing the AFS OFF light to flash.. All charred on the inside.. Looks just like a potentiometer with an O ring around it.. Part is around $300...not under warranty..

You can substitute a 5 cent 1/4 watt resistor....

Check the shop/repair manual for the range of resistance for the leveling sensor and pick something in the middle to start. Then adjust the resistance empirically, trial and error, until the auto-leveling sequence settles at about the right, desired, height.

[srgilbert]

Finally made it home...Turns out the right rear LH height control subassy burned up. causing the AFS OFF light to flash.. All charred on the inside.. Looks just like a potentiometer with an O ring around it.. Part is around $300...not under warranty..

You can substitute a 5 cent 1/4 watt resistor....

Check the shop/repair manual for the range of resistance for the leveling sensor and pick something in the middle to start. Then adjust the resistance empirically, trial and error, until the auto-leveling sequence settles at about the right, desired, height.

Hopefully you can help me. I have a 05 LS 430 with the same problem. The light will flash for minutes and then just go away. My guess is the problem is getting worse and the flashing light happens more frequently. Can anyone help to diagnose what the problem might be and if it is a module can I use a replaceemnt from any other lexus that has AFS?

[curiousB]

I just fixed this problem on my 2004 LS430. The blinking AFS light was due to a faulty ride height sensor on the rear axle. On my LS430 it’s on the driver’s side rear axle just behind brakes.

My symptoms were the AFS light would flash all the time independent of the AFS off switch setting. It didn’t even matter if the lights were on, the blinking occurred day or night. When head lights were on they tended to point too low so they didn’t light up enough of the road (on low beam). I suppose this is the way they are designed so if the mechanism fails the lights don’t point too high an blind oncoming drivers.

The replacement part was $422 and that’s after I called 4 dealers in my area. One dealer had price at $496 before taxes!! So parts pricing is far from standardized. It pays to shop around. This part has a manufacturing cost no more than $40 so you can see the margins dealers make on parts.

The failure mode was the bearing on the sensor arm seized due to water ingress and corrosion. Frankly it’s a poorly designed part and it isn't a surprise to me it eventually failed. Anyway with the bearing seized this caused the actuator arm to force and eventually break the sheet metal mounting bracket for the sensor. This occurs because up and down motion of axe moves the actuator arm and if it can't rotate something else had to give. The sensor is a pretty simple variable resistor (potentiometer). The position determines a resistance divider that sends a voltage signal out proportional to the sensor position. When I opened up the resistor portion of the sensor you could also see the resistive material was worn badly so even if the bearing hadn't seized it was possible the inside was going to become an electrical open and fail soon anyways.

Installation was pretty simple. Removed old sensor and mounted the new one via two bolts on the mounting bracket. Then connected the cable harness. The actuator arm (via a linkage) is held in a locked position presumable for shipping purposes so it doesn’t be turned beyond intended travel range. I also wondered if it came locked in a specific position for initial calibration. So I turned on the car before I connected the actuator arm so the computer could read the factory set position. At this point I could see my flashing AFS light went away so I knew I was on the right track. I then put rear wheel back on and lowered car off jack to level position. Now I connected the actuator arm to the axle bracket. I had to shimmy a bit to get at it but it was not to difficult to reach. I first removed the small screw with that held the actuator frozen and discarded the screw and the small holding bracket. I the fastened the actuator arm aligning it to the same marks one the axle bracket where the old sensor connected. Tightened up the locknut and I was done. I took a test ride and no more flashing AFS light. Tonight I’ll see if more of the road is lit up.

I don’t know if there are additional steps to calibrate the sensor after an install. Maybe someone reading this can add on if there are additional steps to calibrate.

I expect I’ll be doing this repair again in the future (because of poorly designed sensor) but next time it won’t be as much a mystery. I now know why each of the four dealers I called had this part in stock and were quite familiar with what it was. Can you say frequent failure scenario? ;)

[curiousB]

Just to add on. I drove vehicle last night and indeed the low beam headlights were pointed more upwards so I could better see the road ahead. So the annoying blinking AFS light is gone away and the low beam headlights actually light up the road. I’m glad to have this working properly now.

The only open question in my mind now is if the headlights are properly aligned and if I skipped a calibration step with the new sensor. If anyone knows if there is a special calibration step when you replace the axle height sensor, please chime in.

[srgilbert]

Just to add on. I drove vehicle last night and indeed the low beam headlights were pointed more upwards so I could better see the road ahead. So the annoying blinking AFS light is gone away and the low beam headlights actually light up the road. I’m glad to have this working properly now.

The only open question in my mind now is if the headlights are properly aligned and if I skipped a calibration step with the new sensor. If anyone knows if there is a special calibration step when you replace the axle height sensor, please chime in.

My light cooperated through the coldest months however the problem is back withthe warmer weather.....do you happen to have the part number or part name? Is there a way to isolate the problem or is this best left for the dealer?

Thanks!

[curiousB]

Yes that’s the way it failed for me. It started as an intermittent problem and then became more frequent until it was failed all the time. You might be just earlier on in the same failure profile.

The part number for the rear axle sensor I replaced was part number 89408-50060. It’s called a Sensor Subassy. It cost $384.21 before taxes. As I said earlier it’s a potentiometer sensor with an actuator arm connected to the axle to sense the axle height.

Mine was obviously broken as the arm was bent and the bracket broken. Once removed the rotating arm wouldn’t rotate so diagnosis was pretty obvious. Yours may be more subtle. If you have a VOM meter (volt ohm meter) you can measure resistance to see if the sensor has continuity end to end of the potentiometer and then from the wiper to either of the potentiometer (pot). The key is that there are no dead spots where the resistance has worn away inside the pot. So you need to measure resistance from wiper to either end of the pot and turn sensor to be sure it has a reading all across the range of travel. Since the sensor spends 98% of its time in one position that area can get more worn and cause an intermittent break so you have to check to see this isn’t the case.

There is a similar sensor in the front left wheel well for the front axle height. Mine was ok but your failure could be the front one. It is a different looking part but serves the same purpose and is similar electrically.

Good luck

[MBrown1003]

This seems to be a fairly common failure. (A Google search on "Lexus LS430 AFS OFF" yields 2,500 results.) I recognize that most of these cars are beyond warranty, but this seems to me to be an inherent design defect, with a somewhat pricey fix. Has anyone attempted to address this via any consumer protection agencies?

Yes that’s the way it failed for me. It started as an intermittent problem and then became more frequent until it was failed all the time. You might be just earlier on in the same failure profile.

The part number for the rear axle sensor I replaced was part number 89408-50060. It’s called a Sensor Subassy. It cost $384.21 before taxes. As I said earlier it’s a potentiometer sensor with an actuator arm connected to the axle to sense the axle height.

Mine was obviously broken as the arm was bent and the bracket broken. Once removed the rotating arm wouldn’t rotate so diagnosis was pretty obvious. Yours may be more subtle. If you have a VOM meter (volt ohm meter) you can measure resistance to see if the sensor has continuity end to end of the potentiometer and then from the wiper to either of the potentiometer (pot). The key is that there are no dead spots where the resistance has worn away inside the pot. So you need to measure resistance from wiper to either end of the pot and turn sensor to be sure it has a reading all across the range of travel. Since the sensor spends 98% of its time in one position that area can get more worn and cause an intermittent break so you have to check to see this isn’t the case.

There is a similar sensor in the front left wheel well for the front axle height. Mine was ok but your failure could be the front one. It is a different looking part but serves the same purpose and is similar electrically.

Good luck

[curiousB]

Interesting idea. The part is pricey but since it is a sole sourced OEM part they stuff it with very high margin. My guess is the part is at most $40 to mfg so the rest is mfg and dealer margin. I guess I can't fault them for making a profit but when the part is designed so poorly they should "do the right thing" and fix it as a TSB and extended warranty item.

Since I have already done this fix I'm not going to invest any more time in it. I did find a cheaper place to buy it though $270 instead of the near $400 I paid at a dealer...... www.parts.com

http://www.parts.com/oemcatalog/index.cfm?...playCatalogid=0

[jasperaxle]

Add mine to the list. AFS Off started flashing, headlights aimed too low also but for $630 to replace rear height sensor it is all better now. Ouch!

[cincin]

Finally made it home...Turns out the right rear LH height control subassy burned up. causing the AFS OFF light to flash.. All charred on the inside.. Looks just like a potentiometer with an O ring around it.. Part is around $300...not under warranty..

Wayne,

I am having "Headlight Leveling" warning light. I would like to know what the resistance and wattage of the resistor I need.

Thanks!

[curiousB]

Not really a resistance wattage issue. Its a variable resistor much like a volume or balance control in an old radio. I have seen other posts saying you could just replace the ride height sensor with two store bought resistors to simulate a reading but it wouldn't react for changed in height of the axle created by empty or full fuel tank and or trunk.

If you wanted to try a band aide fix you could use two 560 Ohm 1/4watt resistors. Connect them in series on to the voltage feed for the sensor the other end for the ground. The center point of the resistors for the wiper or output side of the sensor. This would simulate the ride height sensor at 1/2 way through its travel. I don't really recommend this but if you don't want to drop $270 at www.parts.com then this is your option. Diagram attached shows you how to wire it up.

[cincin]

Finally made it home...Turns out the right rear LH height control subassy burned up. causing the AFS OFF light to flash.. All charred on the inside.. Looks just like a potentiometer with an O ring around it.. Part is around $300...not under warranty..

You can substitute a 5 cent 1/4 watt resistor....

Check the shop/repair manual for the range of resistance for the leveling sensor and pick something in the middle to start. Then adjust the resistance empirically, trial and error, until the auto-leveling sequence settles at about the right, desired, height.

Hopefully you can help me. I have a 05 LS 430 with the same problem. The light will flash for minutes and then just go away. My guess is the problem is getting worse and the flashing light happens more frequently. Can anyone help to diagnose what the problem might be and if it is a module can I use a replaceemnt from any other lexus that has AFS?

Wayne,

What specific resistor do I need to purchase? Can you describe how to install it?

Thanks

[curiousB]

It’s a cheap simple ¼-1/2 W carbon composition resistor 560 Ohms. The most basic and cheapest they make. Less than $0.10 each. Radioshack (http://www.radioshack.com/product/index.jsp?productId=2062321) or any electronics (Fry’s) store would have them. I think the way to do it would be to take the existing sensor and use that as an "enclosure" for the wired together components. Once you’re sure its working I would flood the inside with rtv/silicone to make it waterproof.

You'll have to figure out best way to solder in the two resistors but the common point has to go to the wiper arm of the replaced pot. The other two resistors go to the opposing ends of the pot. I would remove the old pot wiper arm and carbon track so you won't get both resistances.

Remember you’re defeating the ride height compensation by doing this so with a heavy trunk your lights might point too high and a empty trunk they might point too low.

[blepore]

i tried moving mine up and down to compare the adjustment but, it was a miniscule amount of hieight control over the entire range. I'd say if you go with the Radio Shack fix or the Stealership, you'll never be flashed by anyone assuming you have high beams because of a loaded trunk. I did notice however that they appeared rediculously low when there was a problem with it. Not sure if that is beyond the normal adjustment heights.

[curiousB]

I did notice however that they appeared rediculously low when there was a problem with it. .

That is the initialization of the AFS ECU. It aims lights down to start and raises them to the proper level. When ECU detects error, as in ride height sensor, it points lights down presumably as a safety feature rather than letting lights point to max height. If you just unplug an axle height sensor you'll see the lights revert to this mode and that annoying AFS light will flash and flash and flash and flash....... and flash some more.

[alexmlane]

I just fixed this problem on my 2004 LS430. The blinking AFS light was due to a faulty ride height sensor on the rear axle. On my LS430 it’s on the driver’s side rear axle just behind brakes.

My symptoms were the AFS light would flash all the time independent of the AFS off switch setting. It didn’t even matter if the lights were on, the blinking occurred day or night. When head lights were on they tended to point too low so they didn’t light up enough of the road (on low beam). I suppose this is the way they are designed so if the mechanism fails the lights don’t point too high an blind oncoming drivers.

The replacement part was $422 and that’s after I called 4 dealers in my area. One dealer had price at $496 before taxes!! So parts pricing is far from standardized. It pays to shop around. This part has a manufacturing cost no more than $40 so you can see the margins dealers make on parts.

The failure mode was the bearing on the sensor arm seized due to water ingress and corrosion. Frankly it’s a poorly designed part and it isn't a surprise to me it eventually failed. Anyway with the bearing seized this caused the actuator arm to force and eventually break the sheet metal mounting bracket for the sensor. This occurs because up and down motion of axe moves the actuator arm and if it can't rotate something else had to give. The sensor is a pretty simple variable resistor (potentiometer). The position determines a resistance divider that sends a voltage signal out proportional to the sensor position. When I opened up the resistor portion of the sensor you could also see the resistive material was worn badly so even if the bearing hadn't seized it was possible the inside was going to become an electrical open and fail soon anyways.

Installation was pretty simple. Removed old sensor and mounted the new one via two bolts on the mounting bracket. Then connected the cable harness. The actuator arm (via a linkage) is held in a locked position presumable for shipping purposes so it doesn’t be turned beyond intended travel range. I also wondered if it came locked in a specific position for initial calibration. So I turned on the car before I connected the actuator arm so the computer could read the factory set position. At this point I could see my flashing AFS light went away so I knew I was on the right track. I then put rear wheel back on and lowered car off jack to level position. Now I connected the actuator arm to the axle bracket. I had to shimmy a bit to get at it but it was not to difficult to reach. I first removed the small screw with that held the actuator frozen and discarded the screw and the small holding bracket. I the fastened the actuator arm aligning it to the same marks one the axle bracket where the old sensor connected. Tightened up the locknut and I was done. I took a test ride and no more flashing AFS light. Tonight I’ll see if more of the road is lit up.

I don’t know if there are additional steps to calibrate the sensor after an install. Maybe someone reading this can add on if there are additional steps to calibrate.

I expect I’ll be doing this repair again in the future (because of poorly designed sensor) but next time it won’t be as much a mystery. I now know why each of the four dealers I called had this part in stock and were quite familiar with what it was. Can you say frequent failure scenario? ;)

Hi Curious,

First and foremost I greatly appreciate you finding that part cheaper and explaining this. I have an 05 LS and my lights have been pointing dangerously down and I am just about sick of that annoying AFS light blinking. Also thanks for the explanation of the installation.

By no means am I a mechanic but I can handle some things. I crawled under my car and sure enough on the rear axle, drivers side I saw exactly what it was. My bracket was broken probably from like you said, something has to break. My question is does that part you found come with this new bracket or am I going to have to make one? Thanks a lot for your time!!!!

[curiousB]

Yes sensor includes the sheet metal bracket for mounting.

[alexmlane]

Does anyone know if there are any other sensors like this??? My left rear sub assy was broken at the bracket and locked up so I put the new part on today and it acted right all for about 20 seconds then the lights reverted back to the "standard" position and that stupid AFS light is blinking once again.

Any ideas or help would be greatly appreciated. I dont have a Lexus dealer anywhere nearby so I am pretty much on my own. Thanks for any help or ideas.

[curiousB]

Does anyone know if there are any other sensors like this??? My left rear sub assy was broken at the bracket and locked up so I put the new part on today and it acted right all for about 20 seconds then the lights reverted back to the "standard" position and that stupid AFS light is blinking once again.

Any ideas or help would be greatly appreciated. I dont have a Lexus dealer anywhere nearby so I am pretty much on my own. Thanks for any help or ideas.

There are two sensors. On on drivers side rear axle and driver side front axle. Failure of either one will cause blinking AFS light. Seems unlikely both would fail at the same time though. Maybe you have a dirty contact on the connector you plugged into the new sensor. Perhaps some electronics contact cleaner on the cable side of the connector will do the trick. Are you sure the AFS off switch (on dash) is in the proper position?

[alexmlane]

Does anyone know if there are any other sensors like this??? My left rear sub assy was broken at the bracket and locked up so I put the new part on today and it acted right all for about 20 seconds then the lights reverted back to the "standard" position and that stupid AFS light is blinking once again.

Any ideas or help would be greatly appreciated. I dont have a Lexus dealer anywhere nearby so I am pretty much on my own. Thanks for any help or ideas.

There are two sensors. On on drivers side rear axle and driver side front axle. Failure of either one will cause blinking AFS light. Seems unlikely both would fail at the same time though. Maybe you have a dirty contact on the connector you plugged into the new sensor. Perhaps some electronics contact cleaner on the cable side of the connector will do the trick. Are you sure the AFS off switch (on dash) is in the proper position?

Yes, the AFS switch is off for sure. My rear sensor was broken at the bracket because the of the bearing locked up. I checked the connector and it is clean as a whistle. I guess I should check the front one. I just hate to waste $300 if that isnt it. I only have 37k on my car and I have been driving it for a year with that stupid light blinking. I wish there was a way to make sure my new one isnt messed up. I will share what I find out. Thanks for your help!

[curiousB]

Yes the blinking of the AFS light is incredibly monotonous. My blinked for a few days and I was ready to give the whole car away. Very annoying.

It sounds like you might have multiple problems. That seems strange as its hard to picture two sensors failing at the same time. You said it was dead for 1 year so that isn't exactly on top of each other. Before you drop another $300 on a front sensor you might want to just measure it with a DVM on the ohms scale. I believe the POT is 1.3k ohms so you should measure that from the two end points on the connector. If that reads open circuit (or something much higher than 1300 Ohms) then the POT is bad. You also have to measure the wiper (middle connection) to either one of the ends and see that Resistance varies with movement of arm. You're particularly looking for dead spot(s) where the resistance goes open circuit due to a worn out spot on the POT. If you get open circuit or any dead spots the sensor must be replaced. Don't forget to look at wring or conenctors. A torn wire or dirty connector could give you a failure as well.

You could have problems with the electro mechanical mirrors in the headlights. I didn't have to look at these but if both sensors are good and wiring is fine then that might be next place to investigate.

[alexmlane]

Yes the blinking of the AFS light is incredibly monotonous. My blinked for a few days and I was ready to give the whole car away. Very annoying.

It sounds like you might have multiple problems. That seems strange as its hard to picture two sensors failing at the same time. You said it was dead for 1 year so that isn't exactly on top of each other. Before you drop another $300 on a front sensor you might want to just measure it with a DVM on the ohms scale. I believe the POT is 1.3k ohms so you should measure that from the two end points on the connector. If that reads open circuit (or something much higher than 1300 Ohms) then the POT is bad. You also have to measure the wiper (middle connection) to either one of the ends and see that Resistance varies with movement of arm. You're particularly looking for dead spot(s) where the resistance goes open circuit due to a worn out spot on the POT. If you get open circuit or any dead spots the sensor must be replaced. Don't forget to look at wring or conenctors. A torn wire or dirty connector could give you a failure as well.

You could have problems with the electro mechanical mirrors in the headlights. I didn't have to look at these but if both sensors are good and wiring is fine then that might be next place to investigate.

CuriousB I did find out an answer to your question regarding the calibration of the sensors. I had to take my LS to the dealer today which is 100 miles away and after a 4 hour wait I just walked myself back to the shop area and talked to the tech. I asked him about that having to be calibrated and he said that it would calibrate itself everytime the car cranked. He said he has seen these issues several times before but he couldnt figure out mine. I had to leave my car, pay a $200 diagnostic fee (does this sound accurate) and drive a loaner RX back home so that I can turn around tomorrow and drive back up there.

They were super nice but that service writer I think is out to get me. If they do all this and come back and say I am going to need a new front sensor I am going to be furious! I will let everyone know the end result and the how bad that sock it to me.

[curiousB]

That is strange the sensor didn't fix it when it was obviously broken. Maybe its the ECU that controls it or the other sensor. Let us know what it was so we have other failure scenarios covered here for others...