Fix for ABS, VSC TRAC, VSC OFF, & Brake lights remain on no CEL, or how to repair an ECU

[2002sc430]

Thanks for this thread. I have a 2002 Lexus sc430 and have the same diagnosis of a faulty skid control ECU.unable to communicate with abs ECU via tech stream and I had the brake light and abs light illuminate on my dash. Also the speedometer stopped working. No vsc light, however.

The bad news is a new ECU is on national backorder, and I would hate to shell out thousands of dollars. My mechanic is trying to find someone to repair the circuit board locally but I am not sure how long that will take.

@FJRyder , is this something you could tackle, even though it is a different vehicle? I am willing to pay more than beer money

 

[Ninja Cruiser100]

Thanks for this thread. I have a 2002 Lexus sc430 and have the same diagnosis of a faulty skid control ECU.unable to communicate with abs ECU via tech stream and I had the brake light and abs light illuminate on my dash. Also the speedometer stopped working. No vsc light, however.

The bad news is a new ECU is on national backorder, and I would hate to shell out thousands of dollars. My mechanic is trying to find someone to repair the circuit board locally but I am not sure how long that will take.

@FJRyder , is this something you could tackle, even though it is a different vehicle? I am willing to pay more than beer money

Cross reference the part no on eBay, you will have several choices.

 

[dubdub20003]

Okay, dumb question coming... is the ABS & BA & TRAC & VSC ECU the same as the ABS VSC traction control module, part number 89540-60160, for my 2001 LC?

In reading this thread, I am lost as to whether the ECU and the "control module" are the same thing or not.. post 91 seems to make it clear that it is something different.

I worked through the FSM procedures and think I come out to a Replace ABS & BA & TRAC & VSC ECU.

 

[FJRyder]

That is correct. This fix was specifically for the 89540-60160 ABS VSC module. It can apply to any other module that uses a similar ceramic oscillator component for the clock as this seems to be less reliable than the crystal oscillator. (Just a guess)

I used the abbreviation "ECU" in the title as a general control module. You can say I used this incorrectly as ECU implies Engine Control Module, but I think the vast majority of people got the message.

 

[dubdub20003]

Thanks! New LC owner and didn't want to assume. I can pull codes, so I do not think I have the same issue you have so carefully identified and provided a fix for, but FSM points to a replacement for whatever I do have.

 

[FJRyder]

Thanks! New LC owner and didn't want to assume. I can pull codes, so I do not think I have the same issue you have so carefully identified and provided a fix for, but FSM points to a replacement for whatever I do have.

If you can pull codes then the module is definitely functional and this fix won't do anything.

Probably a wheel position sensor.

Try a Zero Point Calibration ZPC first. It may be just that especially if the vehicle just had an alignment.

 

[MongooseGA]

Thrilled to find this thread. @FJRyder are you still looking for beer donations?

I noticed my Christmas tree lights on a short drive this morning. VSC, ABS, BRAKE. Tried to read codes at the ScanGauge but no codes. Forced cleared the system through the SG and restarted the engine. No lights at start up. Lights come on within 20 yards of driving, still no codes.

I did power-read the whole thread, it sounds like I may be due for this repair.

 

[MongooseGA]

Thrilled to find this thread. @FJRyder are you still looking for beer donations?

I noticed my Christmas tree lights on a short drive this morning. VSC, ABS, BRAKE. Tried to read codes at the ScanGauge but no codes. Forced cleared the system through the SG and restarted the engine. No lights at start up. Lights come on within 20 yards of driving, still no codes.

I did power-read the whole thread, it sounds like I may be due for this repair.

Well...

Has anyone experienced this and then had the problem just go away on its own?

 

[leveeguy]

Well...

Has anyone experienced this and then had the problem just go away on its own?

I’m pretty sure for a day or two my Christmas tree dash went back to normal but all lights returned on and stayed on until I did this fix

 

[Ninja Cruiser100]

Mine may have been intermittent, but never fixed itself. I replaced the module with one off eBay.

 

[badlander]

If you can pull codes then the module is definitely functional and this fix won't do anything.

Probably a wheel position sensor.

Try a Zero Point Calibration ZPC first. It may be just that especially if the vehicle just had an alignment.

FJRyder, you are my hero! Thank you for saving me countless sleepless nights trying to solve this computer issue. The $.40 part you linked from Newark fixed my truck right up. Started her up, lights came on, then went off, just as they should!
One question though, how and where did you attach your oscilloscope leads and did you have the board powered up on a bench or plugged into the vehicle while testing? That chip is so tiny I can't imagine trying to probe it while reaching under the dash board!
Thanks.

 

[FJRyder]

FJRyder, you are my hero! Thank you for saving me countless sleepless nights trying to solve this computer issue. The $.40 part you linked from Newark fixed my truck right up. Started her up, lights came on, then went off, just as they should!
One question though, how and where did you attach your oscilloscope leads and did you have the board powered up on a bench or plugged into the vehicle while testing? That chip is so tiny I can't imagine trying to probe it while reaching under the dash board!
Thanks.

Glad that you were able to get back up and running again

When I diagnosed, I left the module in the car with the lid open. I had a portable oscope and used the standard probe with a ground clip.
There was a little painful bending around to get the right angle but with the right probe top, it's not too difficult to hit the PCB solder pad for the component.

Cheers!

 

[Lexusmech]

Glad that you were able to get back up and running again

When I diagnosed, I left the module in the car with the lid open. I had a portable oscope and used the standard probe with a ground clip.
There was a little painful bending around to get the right angle but with the right probe top, it's not too difficult to hit the PCB solder pad for the component.

Cheers!

Hi FJRYDER...I am new to forum. Brilliant post and diagnosis on a fix. I have the same issue on my 02 sc430 (53,000 miles). No ABS ECU response on Tech Stream, BRAKE and ABS light displayed, no speedometer response. Today the Newark resonator part link is not working and when I search for it separately on the Newark site I can't find it. Can you confirm if the resonator still exists at Newark. Thanks for providing all your research and guidance.

 

[FJRyder]

Just checked the link and its still working:

Digikey also sells it:

https://www.digikey.com/en/products/detail/abracon-llc/AWSCR-4-00CPLA-C33-T4/10232554

 

[DohaCruiser]

Hi, based in Doha, Qatar with a 2000 LX470 which is the wife's daily driver. Last couple of weeks it's been throwing up the ABS, VSC, TRAC and handbrake lights shortly after turning on ignition and accompanied by a warning buzzer. However, the lights and buzzer go off after a (variable amount of) time. Brakes do not work (electric power brakes) when the lights and buzzer are on and can be intermittent when the lights and buzzer go off.

Took the car to a garage who said they performed a calibration and sorted the problem, but on collecting the vehicle it was not the case. They ran an error code check while I was waiting and found no codes. I have left the car with them for now (not sure what they plan to do!) but came across this thread when searching for answers.

It certainly sounds like I could be having the same issue described by @FJRyder but in this thread I didn't see any mention of a buzzer. Does the buzzer indicate a separate issue, or did I just miss it's description?

Given the challenge in finding things here, I'm not sure I can order from the same location as suggested. Is the ceramic resonator the kind of thing an electronics repair shop would have? There's place here that's fixed a couple of household items for me which should have the skills, just not sure if they would have the parts.

Failing find the part here, and while waiting for an order, if the resonator is not replaced will this stop the issue? Not sure the traction control is cutting in too often on the school run so could potentially live without it for a while if it means the brakes work properly and the buzzer stops!

Thanks for any light you can shed on this. Awesome to have a body of knowledge like this to query!

 

[BnvS]

Hi, based in Doha, Qatar with a 2000 LX470 which is the wife's daily driver. Last couple of weeks it's been throwing up the ABS, VSC, TRAC and handbrake lights shortly after turning on ignition and accompanied by a warning buzzer. However, the lights and buzzer go off after a (variable amount of) time. Brakes do not work (electric power brakes) when the lights and buzzer are on and can be intermittent when the lights and buzzer go off.

Took the car to a garage who said they performed a calibration and sorted the problem, but on collecting the vehicle it was not the case. They ran an error code check while I was waiting and found no codes. I have left the car with them for now (not sure what they plan to do!) but came across this thread when searching for answers.

It certainly sounds like I could be having the same issue described by @FJRyder but in this thread I didn't see any mention of a buzzer. Does the buzzer indicate a separate issue, or did I just miss it's description?

Given the challenge in finding things here, I'm not sure I can order from the same location as suggested. Is the ceramic resonator the kind of thing an electronics repair shop would have? There's place here that's fixed a couple of household items for me which should have the skills, just not sure if they would have the parts.

Failing find the part here, and while waiting for an order, if the resonator is not replaced will this stop the issue? Not sure the traction control is cutting in too often on the school run so could potentially live without it for a while if it means the brakes work properly and the buzzer stops!

Thanks for any light you can shed on this. Awesome to have a body of knowledge like this to query!

Aaah @DohaCruiser you can always has someone mail these parts to you from the US or Europe.. also I am sure there are sites similar to digikey or mouser that are local to your market, maybe from China/India that you can find this stuff as well.. Its the desoldering and resoldering that is going to be tricky if you have not done it. So hopefully the shop you have has those skills.

 

[DohaCruiser]

Aaah @DohaCruiser you can always has someone mail these parts to you from the US or Europe.. also I am sure there are sites similar to digikey or mouser that are local to your market, maybe from China/India that you can find this stuff as well.. Its the desoldering and resoldering that is going to be tricky if you have not done it. So hopefully the shop you have has those skills.

Thanks @BnvS - having the car off the road while I wait for the parts will get me in trouble with the wife!

I'm hoping someone can tell me if the resonator can be removed to allow the rest of the systems to work (ABS, etc) in the meantime.

 

[FJRyder]

It certainly sounds like I could be having the same issue described by @FJRyder but in this thread I didn't see any mention of a buzzer. Does the buzzer indicate a separate issue, or did I just miss it's description?

Given the challenge in finding things here, I'm not sure I can order from the same location as suggested. Is the ceramic resonator the kind of thing an electronics repair shop would have? There's place here that's fixed a couple of household items for me which should have the skills, just not sure if they would have the parts.

Failing find the part here, and while waiting for an order, if the resonator is not replaced will this stop the issue? Not sure the traction control is cutting in too often on the school run so could potentially live without it for a while if it means the brakes work properly and the buzzer stops!

To me, this sounds different. Possibly a wheel position sensor or Yaw sensor, connection issue, etc. I never heard the buzzer go off or had the wheels lock up.
Either find a shop that has TechStream (or the computer that can pull Toyota specific codes) or buy the TechStream cable, download the virtual machine and pull the codes yourself. You can also pull codes manually but I prefer seeing things clearly in a GUI in Windows spelled out for me, rather than trying to count the number of flashes on the dash. This is the best way to determine if you have the same issue as me or not. If its the same, you will not be able to go into the ABS screen and pull codes. Instead, there will be an asterisk "*" and no communication or codes. If you can access the ABS computer, then you will be able to pull the codes and begin to diagnose the issue. Note, these are not the standard OBDII codes for generic interface, but specific to Toyota and inaccessible with standard OBDII code reader.

If there are no codes to diagnose, sometimes simply running a Zero Point Calibration can fix the issues seen with this system.

Here is the step-by-step:

How to do a zero point calibration via Techstream - ClubLexus - Lexus Forum Discussion​

LS - 3rd Gen (2001-2006) - How to do a zero point calibration via Techstream - My dealer apparently does not do this after a front alignment even though the technical manual says you should. I would not of known about this if RKW did not mention it, thank you. It's rather simple really. Make...
www.clublexus.com

There is a non-TechStream version of this by using a paperclip.

If the codes don't help you diagnose, then you'll have to go through the many threads on IH8MUD to see if they help. Below are a few random samplings.

Help! My LC won't quit beeping!

forum.ih8mud.com

Traction Control Warning Light and Beeping

forum.ih8mud.com

100 series ABS alarm

forum.ih8mud.com

RTH: Brake light warning and buzzer

forum.ih8mud.com

If in fact you can't communicate with the ABS module, that increases the odd that you have the same issue as me. Then you should pursue this resonator fix. However, you can still attempt to diagnose before repairing as it is not trivial to desolder this component without possibly screwing it up big time. This is using a digital multi meter/ ohm meter to measure the resistance across the three resonator pins. Note, there is a passivation 'gel' coating the components, so best to use pin needle probes or use alcohol to remove this passivation gel.

I believe any of the below component suppliers would have no issues shipping to Qatar:

https://www.arrow.com/

https://www.newark.com/

DigiKey Electronics Home

Digi-Key offers millions of products from thousands of manufacturers, many in-stock quantities available to ship same day. Apple Pay, Google Pay™ & Paypal accepted, order online today!

www.digikey.com

Mouser Electronics - Electronic Components Distributor

Electronic components distributor with huge selection in stock and ready to ship same day with no minimum orders. New electronic parts added daily.

www.mouser.com

But these are all US companies. So perhaps trying somewhere in EU or Asia. Or just Google the part number: AWSCR-4.00CPLA-C33-T4
If none of that works, I can always ship one to you.

 

[DohaCruiser]

To me, this sounds different. Possibly a wheel position sensor or Yaw sensor, connection issue, etc. I never heard the buzzer go off or had the wheels lock up.
Either find a shop that has TechStream (or the computer that can pull Toyota specific codes) or buy the TechStream cable, download the virtual machine and pull the codes yourself. You can also pull codes manually but I prefer seeing things clearly in a GUI in Windows spelled out for me, rather than trying to count the number of flashes on the dash. This is the best way to determine if you have the same issue as me or not. If its the same, you will not be able to go into the ABS screen and pull codes. Instead, there will be an asterisk "*" and no communication or codes. If you can access the ABS computer, then you will be able to pull the codes and begin to diagnose the issue. Note, these are not the standard OBDII codes for generic interface, but specific to Toyota and inaccessible with standard OBDII code reader.

If there are no codes to diagnose, sometimes simply running a Zero Point Calibration can fix the issues seen with this system.

Here is the step-by-step:

How to do a zero point calibration via Techstream - ClubLexus - Lexus Forum Discussion​

LS - 3rd Gen (2001-2006) - How to do a zero point calibration via Techstream - My dealer apparently does not do this after a front alignment even though the technical manual says you should. I would not of known about this if RKW did not mention it, thank you. It's rather simple really. Make...
www.clublexus.com

There is a non-TechStream version of this by using a paperclip.

If the codes don't help you diagnose, then you'll have to go through the many threads on IH8MUD to see if they help. Below are a few random samplings.

Help! My LC won't quit beeping!

forum.ih8mud.com

Traction Control Warning Light and Beeping

forum.ih8mud.com

100 series ABS alarm

forum.ih8mud.com

RTH: Brake light warning and buzzer

forum.ih8mud.com

If in fact you can't communicate with the ABS module, that increases the odd that you have the same issue as me. Then you should pursue this resonator fix. However, you can still attempt to diagnose before repairing as it is not trivial to desolder this component without possibly screwing it up big time. This is using a digital multi meter/ ohm meter to measure the resistance across the three resonator pins. Note, there is a passivation 'gel' coating the components, so best to use pin needle probes or use alcohol to remove this passivation gel.

I believe any of the below component suppliers would have no issues shipping to Qatar:

https://www.arrow.com/

https://www.newark.com/

DigiKey Electronics Home

Digi-Key offers millions of products from thousands of manufacturers, many in-stock quantities available to ship same day. Apple Pay, Google Pay™ & Paypal accepted, order online today!

www.digikey.com

Mouser Electronics - Electronic Components Distributor

Electronic components distributor with huge selection in stock and ready to ship same day with no minimum orders. New electronic parts added daily.

www.mouser.com

But these are all US companies. So perhaps trying somewhere in EU or Asia. Or just Google the part number: AWSCR-4.00CPLA-C33-T4
If none of that works, I can always ship one to you.

Thanks @FJRyder for the detailed response. Update to the situation: went to pick up the car from the garage that couldn't address the issue (one of their attempts to fix was to undertakena ZPC without success) and this time the mechanic said the machanic said he'd checked again and founf an error code (previously no code shown). Issue with the ABS pump apparently.
I took it to another garage that said they can repair/overhaul the pump and they've told me the car is ready to collect. Will see today if they fixed the issue.
As you say, it does seem to have been non-resonator related. Just foe the benefit of anyone else trying to diagnose, the initial issues noted were:
1. ABS, TRC, VSC and parking brake lights illuminating on the dash with the buzzer sounding. This happened shortly after starting the car and would remain for a variable length of time before going off
2. Power brakes not working while the warning light and buzzer sounding and intermittent (pedal sometimes firm and sometimes soft) after the warning lights and buzzer go out
3. Error codes not consistently presented (mechanic was using a professional diagnostic tool) leading to confusion on the source of the problem.

Thanks again, and hope this helps someone!

 

[FJRyder]

Thanks @FJRyder for the detailed response. Update to the situation: went to pick up the car from the garage that couldn't address the issue (one of their attempts to fix was to undertakena ZPC without success) and this time the mechanic said the machanic said he'd checked again and founf an error code (previously no code shown). Issue with the ABS pump apparently.
I took it to another garage that said they can repair/overhaul the pump and they've told me the car is ready to collect. Will see today if they fixed the issue.
As you say, it does seem to have been non-resonator related. Just foe the benefit of anyone else trying to diagnose, the initial issues noted were:
1. ABS, TRC, VSC and parking brake lights illuminating on the dash with the buzzer sounding. This happened shortly after starting the car and would remain for a variable length of time before going off
2. Power brakes not working while the warning light and buzzer sounding and intermittent (pedal sometimes firm and sometimes soft) after the warning lights and buzzer go out
3. Error codes not consistently presented (mechanic was using a professional diagnostic tool) leading to confusion on the source of the problem.

Thanks again, and hope this helps someone!

Glad you got it figured out and thanks for adding the additional info to help others that might have the same situation.