Steering Angle Sensor code on 2002 LX470

[dasgeek]

I need help troubleshooting a steering angle sensor code on a 2002 Lexus LX470.

A little background: A number of years ago my truck started to have a problem with the VSC.

It started out as a problem that would only occure on an angled curve (like a circular ramp from one highway to another). When the truck was leaning to the left, the right wheel would brake hard pulling the truck to the right.

Using the Toyota Tech software I could see that the wheel angle sensor inaccurately indicated the wheel was turning completely to one side. So when the truck would lean it would throw the yaw sensor. The computer sees the truck leaning and the wheel turned all the way to one side and thinks the vehicle is out of control. It tries to correct by braking the opposite wheel.

I ordered a wheel sensor from Toyota and they installed it. It did not correct the problem. The next step in the Lexus Service Manual troubleshooting was a replacement of the ECU for ABS and VSC (PN 89540-60160). Well after replacing the $400 angle sensor, I did not want to spend $2000 to replace the ECU and have it not fix the problem. The issue only happened under very specific condiments so I ignored it.

I found and purchased a used ECU from eBay. I was able to try it this weekend. It did not correct my steering wheel angle sensor showing a false reading of something like 1159 in the TechStream software. So I am a little puzzeled.

So at this point I have replaced the steering sensor and the ECU. I guess there is a chance that the ECU I bought off of eBay has the same problem.

My next step is going to be to try and test the steering sensor per the factory manual with an oscilloscope and test all the wires (I know a failed wire is very unlikely.)

I also wonder if the tech at Toyota replaced the steering angle sensor correctly. The new part did not include the connector so the tech had to transfer the wire terminals to the old connector. I wonder if they mixed them up.

I have seen references to recalibrating the steer angle sensor. I did not find any way to recalibrate the steering angle sensor in the TechStream software and I do not see any references to it in the FSM for the 2002 LX470. I think only trucks with VGRS need to recalibrate the steering angle sensor.

Any advise or suggestions are welcome.

 

[PADDO]

I need help troubleshooting a steering angle sensor code on a 2002 Lexus LX470.

A little background: A number of years ago my truck started to have a problem with the VSC.

It started out as a problem that would only occure on an angled curve (like a circular ramp from one highway to another). When the truck was leaning to the left, the right wheel would brake hard pulling the truck to the right.

Using the Toyota Tech software I could see that the wheel angle sensor inaccurately indicated the wheel was turning completely to one side. So when the truck would lean it would throw the yaw sensor. The computer sees the truck leaning and the wheel turned all the way to one side and thinks the vehicle is out of control. It tries to correct by braking the opposite wheel.

I ordered a wheel sensor from Toyota and they installed it. It did not correct the problem. The next step in the Lexus Service Manual troubleshooting was a replacement of the ECU for ABS and VSC (PN 89540-60160). Well after replacing the $400 angle sensor, I did not want to spend $2000 to replace the ECU and have it not fix the problem. The issue only happened under very specific condiments so I ignored it.

I found and purchased a used ECU from eBay. I was able to try it this weekend. It did not correct my steering wheel angle sensor showing a false reading of something like 1159 in the TechStream software. So I am a little puzzeled.

So at this point I have replaced the steering sensor and the ECU. I guess there is a chance that the ECU I bought off of eBay has the same problem.

My next step is going to be to try and test the steering sensor per the factory manual with an oscilloscope and test all the wires (I know a failed wire is very unlikely.)

I also wonder if the tech at Toyota replaced the steering angle sensor correctly. The new part did not include the connector so the tech had to transfer the wire terminals to the old connector. I wonder if they mixed them up.

I have seen references to recalibrating the steer angle sensor. I did not find any way to recalibrate the steering angle sensor in the TechStream software and I do not see any references to it in the FSM for the 2002 LX470. I think only trucks with VGRS need to recalibrate the steering angle sensor.

Any advise or suggestions are welcome.

Yes, VGRS is an '03 + thing. In the absence of fault codes to chase I'd do a zero point calibration. IIRC the FSM states a zero point cal should be done if you change the ECU, at least for 03+. Notwithstanding a zero point cal won't hurt.

 

[dasgeek]

The TechStream software does not offer a zero point calibration on my 2002 LX470. It does offer a recalibration of the Yaw sensor and one other that I can not recall right now. I am waiting on an oscilloscope that I ordered from Amazon and I will test the steering angle sensor per the FSM. I will report back. I am also going to test the continuity of the wires.

I do think it is possible that the used ECU I received has the same problem as mine.

 

[haas]

any update on the problem? I am having the VSC braking issues on curves at highway speeds...

 

[uHu]

Steering angle sensor zeroing on non-vgrs:
The only indication on a way to do this is from a friend on the local lc forum. It looks like the method is to disconnect the steering angle sensor, then power up the ecu (ign on), then off again, reconnect the sensor, and power up again - with the steering straight.

What he did was to open up the steering wheel assembly and the sensor to see if there is a way of adjusting it. After looking a bit, he found that the steering sensor was giving a zero angle with the steering straight (it used to be way out), and retracing what he had done, he found that this is the method.
I will try it myself one day - but mine is only 20 something out.

 

[PADDO]

Good info @uHu. For those with AHC if you have a gross SAS error then this will impact your variable suspension too. The FL & FR, RL & RR shock accuator and damper assemblies are normally hydraulically connected (through solenoid gate valves FG and RG) for straight line driving and isolated to stiffen up and reduce body roll for cornering using the steering angle sensor feedback and wheel speeds. Using Techstream you can observe and record when the normally open FG and RG actuate as a function of steering input whilst driving which is great for finding anomalies or confirming everything is operating as designed.

 

[haas]

I have an '00 lx470, so I'm dealing w/ the AHC. Is the "unplugging SAS zeroing" different than the techstream zeroing? I've tried the techstream yaw/steering zero and I'm still having VSC issues.

@PADDO, will driving and recording techstream data show me which sensor is failing (ABS, SAS, etc?) when the VSC turns on? Not quite sure where to start and replacing "possibly bad" sensors is an expensive hobby...

 

[PADDO]

VGRS for the 03+ vehicles have Techstream zeroing and calibration options that earlier models don't but the "unplugging sensor" method and powering the ECU (erases stored memory and forces reinitialization I suspect) probably achieves the same outcome wrt the steering angle.
You can select from 50-60? or so fields within Techstreams data lists to graphically display and record something like 300sec so you may be able to capture what sensors are reporting when the VSC inadvertently operates.

 

[haas]

looks like I'm going on a test drive today!

 

[haas]

I zeroed the steering angle sensor according to @uHu's instructions and took the LX for a test drive. The good news, is I live in the mountains off a windy highway, but the bad news is the 70mph curved canyons are still setting the VSC off...

I recorded the data list on techstream during VSC malfunctions. I don't see too much out of the ordinary. Here is a list of questionable items...Does any of this seem odd, @PADDO?
1. The solenoid relay is always on...Is that the ABS solenoid relay? Should that always be on?
2. The High hydraulic Boost SW came on when VSC went off...but that seems normal as the system slams on the brakes.
3. The Steering Angle Sensor jumps up (usually from 5 to 30-45ish) when then VSC goes off...but I usually swerve when the brakes are applied.
4. Every once in a while one of the wheel speed sensors reads a 1mph difference. It's not the same wheel every time and it doesn't seem to set off the VSC (it happens WAY more often than the VSC goes off). There's never more than one sensor reading a different mph and it's never more than 1mph off the other three sensors.
5. The deceleration sensors often don't ready the same G's. Sensor 1 typically ready .05G's at stop. Sometimes it reads the same as other and sometimes reads about .05G's different than sensor 2.
6. The VCC/TRAC OFF SW is off and does not read ON when the VCS goes bananas.

 

[2001LC]

Just a thought, make sure wheel bearings and snap ring gap at hub flange is tight. If hub is move in and out this may give slight difference at ABS wheel speed sensor. Make sure all sensors are in good condition (mounts) and each retaining bolt is torque.

 

[haas]

Just a thought, make sure wheel bearings and snap ring gap at hub flange is tight. If hub is move in and out this may give slight difference at ABS wheel speed sensor. Make sure all sensors are in good condition (mounts) and each retaining bolt is torque.

I did. The wheel bearing retainer nuts were crazy loose. I could move the hub around, not just the tire. I tightened them and installed snap rings & made sure they were tight. I also removed each ABS wheel speed sensor: inspected, cleaned and reinstalled.

 

[2001LC]

Did you see any nicks on sensor or matching back side hubs, indicating they took a hit?
What did you set wheel bearing pre-load at?
What was final snap ring gap (with axle pulled out really hard)?

 

[haas]

1. sensors looked great minus 255k miles of being behind a wheel. No dings...just a little dirt caked on the outside.

2. I used what I call a modified Landtank's method...Tighten the inner nut to 45 lbs/ft, rotate, back off and repeat, then just until you feel resistance. Install the lock washer, then torque the outer nut to 45 lbs/ft.

Here's where the modified comes into play...I just moved and have a 2 car garage worth of tools stacked in an 8x20' trailer...Couldn't find the torque wrench. SO I winged it. I'e done three front axle rebuilds on an 80 and a few on an old Willys...never on a 100 I figured this method would be good enough to test the wobbly wheel VSC theory. The driver side wheel bearings looked like they had never been touched in 255K miles and the passenger side looked like it had been taken apart with a hatchet, not cleaned and repacked with a different grease. As soon as I figure out this VSC fiasco, I'll be rebuilding the front end. I'll take care to find the torque wrench by then!

3. Hmmm...snap ring gap, eh? Guess I should go digging for the fractional caliper...I do remember pulling the axle out (really hard) on the passenger side as far as it would go and I was initially worried that I wouldn't be able to get the snap ring in. Well, sure enough there was just enough room. Snug fit. The driver's side had maybe a 1/16" play according to my guess-o-meter and spotless memory!

 

[2001LC]

1. sensors looked great minus 255k miles of being behind a wheel. No dings...just a little dirt caked on the outside.

2. I used what I call a modified Landtank's method...Tighten the inner nut to 45 lbs/ft, rotate, back off and repeat, then just until you feel resistance. Install the lock washer, then torque the outer nut to 45 lbs/ft.

Here's where the modified comes into play...I just moved and have a 2 car garage worth of tools stacked in an 8x20' trailer...Couldn't find the torque wrench. SO I winged it. I'e done three front axle rebuilds on an 80 and a few on an old Willys...never on a 100 I figured this method would be good enough to test the wobbly wheel VSC theory. The driver side wheel bearings looked like they had never been touched in 255K miles and the passenger side looked like it had been taken apart with a hatchet, not cleaned and repacked with a different grease. As soon as I figure out this VSC fiasco, I'll be rebuilding the front end. I'll take care to find the torque wrench by then!

3. Hmmm...snap ring gap, eh? Guess I should go digging for the fractional caliper...I do remember pulling the axle out (really hard) on the passenger side as far as it would go and I was initially worried that I wouldn't be able to get the snap ring in. Well, sure enough there was just enough room. Snug fit. The driver's side had maybe a 1/16" play according to my guess-o-meter and spotless memory!

100 bearings do need to be tight, one set I did Saturday, took ~47ft lbf on adjust nut just to get within FSM pre-load range of 9.5 to 15lb breakaway preload on spring scale.

The snap ring can't be to tight FSM is <0.20 MM gap max. To wide a gap and we get lateral movement, which saw on teeth of hub flange and axle. This also pounds on snap ring, flange contact surface, additional front drive shaft outboard surface will pound on axle bushing. If snap ring or hub flange contact surface damaged, reading will be inaccurate. I just did one very loose as PO's mechanic had totally botch the job. Hub flange, snap ring and axle busing all damaged. In fact I just got of phone with my local Toyota parts guy, order a thick 2.60 mm snap ring (two or three thicknesses up from standard). This will bring my gap down to ~0.03 mm, if I measured correctly with my feeler gage. I use puller to make sure axle pulled out very tight. Puller very helpful especially when one has just greased axle bushing and needle bearing.

You stated about 1 mph difference in speed sensor, also Steering Angle Sensor jumps. Could it be you have multiple issues in front end with looseness. i.e. steering rack, ball joint, UCA & LCA bushings, wheel bearing, axle busing (snap ring gap)!

 

[haas]

On the axle with the snap ring gap, I did notice a bent snap ring. I pounded it straight and pulled it together a bit before reinstall. Do you think this axle movement could be setting off the VSC? where do you order a thicker snap ring?

Steering is super tight. With the vehicle on jack stands, the slightest movement at the tire results in the steering column twisting.

I'm not too sure about the random 1mph wheel speed differences. Didn't know if that was a negligible amount? It doesn't seem to be the catalyst that sets off the VSC as the VSC often goes off with all wheel speed sensors reading the same. It's hard to tell about the SAS, though. I typically have the jerk the steering wheel to the side when the VSC slams on the brakes. It all seems to happen in the same frame in techstream...I'd hate to replace the $350+ SAS and have that not be the cause of the VSC braking.

This car was a freebie from my wife's uncle. He's the original owner and states he's never had this issue. He's also offered to pay to get it fixed...If I can't figure this out, I'm just going to take it to a mechanic/dealer in Denver....Any recommendations?

One more thing popped in my mind...The only thing I did to the car prior to driving it was to remove and ground the fog lamp wire out of the harness behind the steering wheel. I wanted the fog lights to turn on with the high beams....I did not remove the steering wheel, just the two split covers behind the wheel. The wiring loom I messed with was not near the SAS...it was just the loom that goes to the light switches off the column...

 

[2001LC]

On the axle with the snap ring gap, I did notice a bent snap ring. I pounded it straight and pulled it together a bit before reinstall. Do you think this axle movement could be setting off the VSC? where do you order a thicker snap ring?

Steering is super tight. With the vehicle on jack stands, the slightest movement at the tire results in the steering column twisting.

I'm not too sure about the random 1mph wheel speed differences. Didn't know if that was a negligible amount? It doesn't seem to be the catalyst that sets off the VSC as the VSC often goes off with all wheel speed sensors reading the same. It's hard to tell about the SAS, though. I typically have the jerk the steering wheel to the side when the VSC slams on the brakes. It all seems to happen in the same frame in techstream...I'd hate to replace the $350+ SAS and have that not be the cause of the VSC braking.

This car was a freebie from my wife's uncle. He's the original owner and states he's never had this issue. He's also offered to pay to get it fixed...If I can't figure this out, I'm just going to take it to a mechanic/dealer in Denver....Any recommendations?

One more thing popped in my mind...The only thing I did to the car prior to driving it was to remove and ground the fog lamp wire out of the harness behind the steering wheel. I wanted the fog lights to turn on with the high beams....I did not remove the steering wheel, just the two split covers behind the wheel. The wiring loom I messed with was not near the SAS...it was just the loom that goes to the light switches off the column...

Snap ring is Dealer parts. Snap ring is not a reusable (FSM) if bent you'll not get good reading with feeler gauge. It may also pop off. Snap ring is often overlooked, but should always be set to spec, 1/16th of inch is way to wide a gap.

Steering rack side to side play should be checked with tires on ground. I'm replace bushing on most 100 over 150K miles I see. If any fluid leaks on rubber bushing even sooner.

Altering electrical can have many adverse effects, even weak battery can be problem. I deal with stock only (no mods) so can't help here.

Many 100 owners never have a problem. They just drive until it stops, then take to shop on corner that doesn't have a clue on the specifics of our rigs. I've seen some real damage that many an owner has paid good money for, damage do to incompetence of mechanics. Luckily with these rigs are repairable, they are tanks.

Getting front end baseline to factory spec would be good starting point, that is all bushing & bearing set to spec includes AHC.

All tires should also be the same with roughly same thread depth.

Slee Off Road in Golden Co. is one of the best. Call and see if you can get on schedule. Dealers are good, but it depends on which mechanic you get.

 

[haas]

@PADDO, any thoughts on the techstream data above?

Unfortunately, Slee has got a 2 week wait for general maintenance. ARGH!

Steering on the ground is also tight. I have a gravel driveway and can move tires side to side by hand a bit...the slightest move in tire results in steering column turning.

Altering electrical to get fog lights...Could always stick with the "if it ain't broke, don't fix it" mantra...where's the fun in that? It was removing one wire from the harness and grounding it...maybe I should try putting it back and seeing results

My current DD is a '93 Chevy 1 ton w/ a 12v cummins and the wife drives the '96LX in signature...I love old cars cuz they're easy to diagnose & fix...less sensors and computers! The only thing I've taken a car into a shop for in 18 years was a paint job on the Chevy a few years back!

Bushings aren't leaking, just dry cracked. Need to be replaced, but there doesn't seem to be any crazy rattle that might cause this VSC mess.

Tires are tired. 6 years old but 1/3rd tread left. They are dry and cracking...will be replaced as soon as I can fix this VSC mess.

AHC has been addressed (save for new rear springs): This past weekend I leveled out the front R&L by cranking the torsion bars then cranked again to balance AHC....6.8 in the front and 6.8 in the rear after installing 30mm Slee spacers...needs new springs in rear to bring pressure's down a bit more...

 

[PADDO]

I zeroed the steering angle sensor according to @uHu's instructions and took the LX for a test drive. The good news, is I live in the mountains off a windy highway, but the bad news is the 70mph curved canyons are still setting the VSC off...

I recorded the data list on techstream during VSC malfunctions. I don't see too much out of the ordinary. Here is a list of questionable items...Does any of this seem odd, @PADDO?
1. The solenoid relay is always on...Is that the ABS solenoid relay? Should that always be on?
2. The High hydraulic Boost SW came on when VSC went off...but that seems normal as the system slams on the brakes.
3. The Steering Angle Sensor jumps up (usually from 5 to 30-45ish) when then VSC goes off...but I usually swerve when the brakes are applied.
4. Every once in a while one of the wheel speed sensors reads a 1mph difference. It's not the same wheel every time and it doesn't seem to set off the VSC (it happens WAY more often than the VSC goes off). There's never more than one sensor reading a different mph and it's never more than 1mph off the other three sensors.
5. The deceleration sensors often don't ready the same G's. Sensor 1 typically ready .05G's at stop. Sometimes it reads the same as other and sometimes reads about .05G's different than sensor 2.
6. The VCC/TRAC OFF SW is off and does not read ON when the VCS goes bananas.

Nothing jumps off the page as out of the ordinary and in the absence of fault codes I guess the best approach is to continue along the lines "why does the vehicle think it's in a skid?"
1. Unsure which solenoid relay referenced
2. Agreed, normal
3. I believe you're seeing the swerve, 30-45ish isn't much when put in context of lock to lock turning of the steering wheel (3.25ish turns?) equates to about +1150 to -1150
4. Speed is rounded to whole numbers so imo 1 mph delta is normal i.e. It could be 60.49 mph (60) or 60.51 (61)
5. I've read 0.5Gs whilst stopped too, with no VSC issues
6. Dunno what that may mean
Sorry you didn't find the smoking gun. Just spewing out thoughts, mostly already covered but the vehicle could think it's slipping if: tires not same size/pressures out, steering rack movement and front end play, wheel bearings, yaw/pitch/decel acelerometers out, excess body roll/dive.

 

[2001LC]

Two weeks wait for Slee off Road is not bad.

I find best way to check steering rack bushing is with skid plate off, wheel/tires on hard surface. Without a helper, set up video camera pointed at large horse shoe bushing on PS of steering rack, then start engine, turn steering wheel back and forth while recording. I'll bet you'll see steering rack move through horse shoe mounting rubber bushing. Slee has the replacement bushing, or you can order online. Whiteline poly is what I've used, which are popular here with mud members

The loose wheel bearing you found indicates poor or improper maintenance. This is very common as most mechanics use old school and set bearings loose. A big red flashing sign is tooling marks on hub flange and locking & adjusting nuts. I see these things and I know it's been done improperly every time.

Steering rack alone wouldn't normal set off VSC. Add in loose wheel bearing and other front end components out of spec and it may. Base line of all front end components is just a first step. It also just good practice for a use rig of this age.

You had one very loose wheel bearing, further inspection of hubs & ABS sensors is warranted. Few mechanic properly set these up.