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#ABS-2E - Checking Codes and Bleeding

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 Post subject: ABS-2E - Checking Codes and Bleeding
PostPosted: Mon Oct 01, 2018 6:54 pm 
First Gear
Joined: Thu Feb 10, 2005 8:48 pm
Posts: 117
Location: Portland, OR
The ABS-2E system has not had a dedicated write-up on this forum and with my recent purchase of the ABS-2E factory service manual supplement, I thought I would share some of the basics all in one thread.

First off, let's cover how to identify the ABS braking system on your 90 to 94 Legacy

Nippon
Brake lines come into the top of the hydraulic control unit (HCU) and HCU has bleeder ports on top.
ABS ECU is located under the passengers seat and has red light for reading ABS trouble codes
ABS ECU can store only a single error code and error code list is limited

Bosch
Brake lines come into the top of the HCU in shape of a square
ABS ECU is located under the passengers seat and has red light for reading ABS trouble codes
ABS ECU can store only a single error code and error code list is limited

ABS-2E
Brake lines come in top of HCU lined up in a straight line
ABS ECU is located under the passengers seat and does NOT have a red light for reading ABS trouble codes
ABS ECU can store up to three error codes and error code list is expanded from the older versions

The following information is specific to the ABS-2E system and comes straight from the ABS-2E FSM supplement or from The End Wrench Article on Legacy ABS systems.

ABS-2E Checking Error Codes
Just underneath the driver's side fuse panel (behind the plastic kick-panel trim), you will find a small white two terminal connector. The white connector terminates a single red wire and single green wire. The terminal connected to the red wire is referred to as the "L" terminal. The terminal connected to the green wire is referred to as the "K" terminal. There should also be one or two diagnostic jumpers taped to the same wiring bundle as the white connector. These diagnostic jumpers have black wires and are continuous with vehicle ground (ie. they are diagnostic grounding jumpers).

To check the ABS codes, connect one of the diagnostic jumpers to the "L" terminal and then turn the ignition switch to the ON position. The ABS light will flash in similar fashion as the check engine light to indicate the stored ABS error codes. Long flashes are tens digit, short flashes are ones digit. Code 11 will always be present and there can be up to three other fault codes in memory. I will list the ABS-2E codes in a follow-up post.

Note: In the linked image above, I have re-soldered two diagnostic jumpers into place to provide a second jumper for convenience. Your jumpers will look different.

ABS-2E Clearing Error Codes
Connect the diagnostic jumper to the "L" terminal and turn the ignition switch to the on position. Clear codes by alternately disconnecting and reconnecting the diagnostic jumper to terminal "L" three times within a span of 12 seconds. When the codes are cleared, you may be able to hear the pump and valve relays at the HCU cycle as the ABS ECU performs an initializing pre-check. With the diagnostic jumper still connected to terminal "L", you should also now only see code 11 being displayed by the ABS light.

Disconnect the diagnostic jumper before operation.

ABS-2E Air Bleeding
Bleeding the ABS-2E system is a three step process.

Step 1.
Bleed brakes using conventional method listed in the 92 FSM. I've found that vacuum pump bleeding does not work very well.

Brake Bleeding Order:
1. Right Front
2. Left Rear
3. Left Front
4. Right rear

Step 2.
Initiate ABS-2E Sequence Control to run the ABS pump and cycle the ABS solenoid valves to purge trapped air out of the ABS HCU.

Initiating ABS-2E Sequence Control Mode:
1. Start with ignition switch in the OFF position
2. Connect diagnostic jumpers to both ABS-2E terminals "L" and "K".
3. Turn the ignition switch to ON and watch the ABS light
4. When the ABS lamp goes off, immediately press and hold the brake pedal
5. Continue depressing the brake pedal until the ABS pumps stops running. Sequence Control mode is complete when the ABS pump turns off.
6. Release brake pedal
7. Turn ignition switch to OFF position
8. Disconnect the diagnostic jumpers

Step 3.
Re-bleed the brakes using the same bleeding order as provided in Step 1. You should see a few additional air bubbles at each wheel slave cylinder when re-bleeding.

Hope this helps someone out there from not having to employ the old "take the car out and lock up the brakes" method of attempting to get the air out of the brake system, which does not purge air from the HCU as well as the sequence control method provided here. Plus, you can employ the sequence control method safely with the jar on jack stands and the wheels off, which makes bleeding the brakes much easier.

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1987 VW Westfalia Vanagon - EJ22T Powered
1994 Legacy Touring Wagon


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 Post subject: Re: ABS-2E - Checking Codes and Bleeding
PostPosted: Wed Oct 03, 2018 2:12 am 
First Gear
Joined: Thu Feb 10, 2005 8:48 pm
Posts: 117
Location: Portland, OR
ABS-2E Error/Trouble Codes

0 - Trouble in the ABS warning light drive circuit (ie. ABS lamp or lamp circuit is faulty)

11- Start Code

21 - Faulty ABS Sensor, Front Right Wheel Sensor (Open circuit or excessive voltage)
23 - Faulty ABS Sensor, Front Left Wheel Sensor (Open circuit or excessive voltage)
25 - Faulty ABS Sensor, Rear Right Wheel Sensor (Open circuit or excessive voltage)
27 - Faulty ABS Sensor, Rear Left Wheel Sensor (Open circuit or excessive voltage)

22 - Faulty ABS Sensor, Front Right Wheel Sensor (No speed signal input, short circuit condition)
24 - Faulty ABS Sensor, Front Left Wheel Sensor (No speed signal input, short circuit condition)
26 - Faulty ABS Sensor, Rear Right Wheel Sensor (No speed signal input, short circuit condition)
28 - Faulty ABS Sensor, Rear Left Wheel Sensor (No speed signal input, short circuit condition)

29 - Faulty Tone Wheel etc.

31 - Faulty Solenoid Valve in HCU, Front Right Wheel Control
33 - Faulty Solenoid Valve in HCU, Front Left Wheel Control
39 - Faulty Solenoid Valve in HCU, Rear Wheels Control

41 - Faulty ABS Control Unit

42 - Source Voltage is Low

51 - Faulty Valve Relay

52 - Faulty Hydraulic Motor and/or Motor Relay

54 - Faulty Brake Light Circuit

56 - Use of improper ABS Control Unit Specification (I think this means that you plugged in an ABS ECU that is non-compliant with the ABS-2E system)

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1987 VW Westfalia Vanagon - EJ22T Powered
1994 Legacy Touring Wagon


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 Post subject: Re: ABS-2E - Checking Codes and Bleeding
PostPosted: Mon Oct 08, 2018 5:53 pm 
Site Admin
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Joined: Tue Oct 15, 2002 11:37 am
Posts: 27325
Location: Houston, Tx
Excellent information! Thank you for sharing. Here is the Endwrench article you shared with me.

https://main.experiencetherave.com/suba ... Wrench.pdf

I will add to the sticky as well.

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Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm


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 Post subject: Re: ABS-2E - Checking Codes and Bleeding
PostPosted: Mon Oct 08, 2018 6:08 pm 
First Gear
Joined: Thu Feb 10, 2005 8:48 pm
Posts: 117
Location: Portland, OR
Yep. That's it. Let me know if you want me to scan the ABS-2E FSM supplement for posting as well.

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1987 VW Westfalia Vanagon - EJ22T Powered
1994 Legacy Touring Wagon


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 Post subject: Re: ABS-2E - Checking Codes and Bleeding
PostPosted: Mon Oct 08, 2018 6:59 pm 
Site Admin
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Joined: Tue Oct 15, 2002 11:37 am
Posts: 27325
Location: Houston, Tx
Yeah, if you don't mind doing that I think that would be great.

Thanks!

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Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm


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 Post subject: Re: ABS-2E - Checking Codes and Bleeding
PostPosted: Thu Oct 11, 2018 11:56 pm 
First Gear
Joined: Thu Feb 10, 2005 8:48 pm
Posts: 117
Location: Portland, OR
Here it is. It would be great if you could provide an alternate hosted location for this just in case Google ever changes the URL path.

1992 Legacy Service Manual ABS-2E Supplement

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1987 VW Westfalia Vanagon - EJ22T Powered
1994 Legacy Touring Wagon


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 Post subject: Re: ABS-2E - Checking Codes and Bleeding
PostPosted: Tue Oct 16, 2018 6:08 pm 
Site Admin
Site Admin
Joined: Tue Oct 15, 2002 11:37 am
Posts: 27325
Location: Houston, Tx
Thank you for providing! I've rehosted on my server.

https://experiencetherave.com/subaru_ma ... lement.pdf

_________________
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm


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