Hayk

iTrader: (1)

Updated original post August 21, 2016:

Solution: replace bad alternator. Poor voltage created numerous ABS error codes 21-27

How to retrieve ABS Codes:
1. Open the Diagnostic Port under the hood (near the engine dog bone mount/intake plenum)
2. Remove metal Shorting Pin (looks like a fuse without the plastic part)
3. Connect Tc and E1 pins with a paper clip
4. Turn the ignition key to the ON position without starting the engine
5. Each combination of flashes of the ABS light is a digit. Ex. 23 would be 'blink blink....pause.. blink blink blink' *the codes will show up multiple times, so don't worry if you miss them the first time*

How to Erase ABS Codes:
1. Retrieve the codes as explained above
2. Pump the brake pedal 10 times within 5 seconds
3. Codes will be cleared when the ABS light flashes rapidly nonstop.

How to check your Wheel Speed Sensors (WSS):
To enter the special WSS test mode, turn off the ignition. Leave the short pin in the ABS check connector and use a jumper wire to connect terminals Ts and E1. Engage the parking brake and start the engine. If the system is in the special diagnostic mode, the ABS light will flash at a rate of four times per second.

Drive the vehicle straight ahead at a speed above 50 mph. The ABS light will stop blinking as soon as you exceed 28 mph, then blink once when you hit 50 mph. As soon as youÂ’ve seen the blinks, the test is complete and you can stop the vehicle.

To retrieve the wheel speed sensor codes, use the same diagnostic procedure that you would use to read the normal ABS codes. Remove the short pin from the ABS check connector and jump Tc to E1. If a problem was detected in any of the wheel speed sensor circuits, youÂ’ll find one or more codes.



Okay back to the original post:

My ABS light has come on today - on the way to work and on the way back.

My ABS motor reads:

"Toyota 44540-33010
133200-4000
Denso Made in Japan
Manufactured under
license of Bosch"

So I don't know if it's Denso or Bosch.....

I removed the pin and jumped Tc with E1, as described in this post on Toyota Nation.
http://www.toyotanation.com/forum/2051226-post5.html

Here is what I saw.

VIDEO REMOVED. Read post #6.

What does this mean?

PFB

If you're referring to your '98 Lexus, than you should not have done that. Your car is obd 2 compliant, so you should be using a code reader to retrieve the codes. Your reference was to a car that is not obd 2 compliant.

Don't do that or you may end up shorting something. Come to think about it, I'm not even clear as to what you did.

Phil

CANDYAPPLE

iTrader: (1)

Well first off must feel great having a full tank of gas in these times,lol. But on a serious note, is the pic with the car in ignition or running, because if you have the check engine and airbag light on with the car running, then you might have to reset the computer via a scanner and see if it comes back. You might have just triggered the computer into thinking something is wrong when you touched actuator

Hayk

iTrader: (1)

This was with ignition in the ON position - engine off.

I have an OBD2 but it doesnt read ABS lights. I shorted those two pins with a paper clip in the diagnostic port next to the Intake Plenum.

CANDYAPPLE

iTrader: (1)

i dont think anyone can read the abs light, i know when one of my sensors went bad, they had to test them individually.

Hayk

iTrader: (1)

It's listed in the factory service manual.

I finally understand how to read it. You have to count how many times the ABS light blinks. For example, code 24 would be "blink, blink(2)....pause...blink blink blink blink(4)...pause" So looking at the video, it looks like I recorded: 21, 22, 23, 24, 25, 26, 27, and then it's cut off. This doesn't really make sense, unless my system is junk. Also, there isn't anything in the FSM for 25, 26, 27.



There is a slightly different procedure for checking the speed sensors. It involves starting the engine and driving over 28mph.

randal

It looks to me like you are getting a code for each wheel(21,22,23,24) and it is highly unlikely that each sensor would have gone bad. So I would suspect a common issue such as a bad connector somewhere or a common ABS computer on the fritz. Perhaps unplugging and cleaning the connector would fix the issue. I do not know where that connector might be on your car...sorry. Just a thought.

Hayk

iTrader: (1)

My ABS motor makes a loud noise on every start-up. It can be heard the best with ignition in the ON position. It also gives some feedback through the brake pedal when that happens.

So you might be right about a bad motor.

GS4_Fiend

iTrader: (22)

Have you try changing the brake fluid yet? Worth a shot, cuz the ABS unit is $$$

Hayk

iTrader: (1)

I have. I changed it last August when I overhauled my front brakes.

Hayk

iTrader: (1)

All of my previous codes were cleared, so that I could start fresh. The light came on again a few days ago, and this time it was only #21. I cleared it as well to see if it will return.

The manual reads:

Detection Item:
Open or short circuit in 2-postion solenoid circuit for right front wheel.

Trouble Area:
ABS Actuator
SFRR or SFRH circuit (what do these acronyms stand for?)

edit: I just realized that I forgot to take out the shorting pin.

Please explain to me what this means.

1987

SFRR and SFRH circuit's are between the ABS & VSC Actuator that apply and release the brakes and the Skid Control ECU that tells them to do so.
If all the connections are good and you have continuity between the wires, the fault will be the ABS unit.

Hayk

iTrader: (1)

The ABS issue has become much more common recently. I get the ABS + TRAC OFF on almost every drive that I take. Scanned the codes today and got 21, 22, 23, 24, 25, 26, 27, and 28. Cleared the system and went for a drive, the lights came on almost immediately. Checked it again and recorded 24.

I found a PDF of an old Lexus Technical Manual for the ABS/TRAC system.
http://www.autoshop101.com/forms/brake12.pdf

ABS/TRAC Related Codes
21: Open or short circuit in 3-position solenoid of FR Wheel
22: Open or short circuit in 3-position solenoid of FL Wheel
23: Open or short circuit in 3-position solenoid of RR Wheel
24: Open or short circuit in 3-position solenoid of RL Wheel
25: Open or short circuit in master cylinder cut solenoid valve circuit of TRAC brake actuator
27: Open or short circuit in reservoir cut solenoid valve circuit of TRAC brake actuator

TRAC Related Codes
24: Open or short circuit in step motor circuit of sub-throttle actuator
25: Step motor does not move to a position decided by TRAC ECU
26: Leak at sub-throttle position sensor or stuck sub-throttle valve

Not sure what 28 is about, but I think that's the least of my worries at this point. Does anyone know where I should even begin to diagnose? I have no idea how this system operates.

Hayk

iTrader: (1)

Found an electrical diagram of the ABS/TRAC system in the FSM page 190. It has all those SFRH, SFRR, etc circuits labelled and specifies which pins are supposed to have what. I'll try to do a bit of electrical diagnosis tomorrow.

Hayk

iTrader: (1)

Okay, status update.

Found a special Wheel Speed Sensor test. I did the test and no codes came back, so my speed sensors are perfectly fine.

I then looked at my electrical diagrams and saw how the ABS/TRAC ECU is connected to the ABS/TRAC ACTUATOR. So I decided to start testing the wires for continuity.

Pins 13A/9B(SFRH) and 26A/3B(SFRR) have perfect continuity


Pins 25A/10B(SRLH) and 12A/4B(SRLR) are also good. Access to SFLH, SFLR, SRRH, and SRRRs is very difficult and I'm not sure if it's worth the effort.


Do you guys think I should replace my ABS Module? It's the black box that's attached to the ABS Pump. The module has a circuit board inside, so maybe that's where the solenoid short/open circuit codes are originating. During my searches, I've noticed that it's a common issue with Bosch ABS systems. There are videos of people replacing them on Volvo's, VW's, and Audi's. Reference photo: