Brake and ABS light still on after replacing cylinder.

[Dimitri13]

'92 Astro ABS. Little backstory; van sat in a carport for 8 years, I replaced all ignition and fuel components, and got it back on the road. I replaced the tires with 215 (stock was 205, but 215 was an option from the factory). It drove and stopped fine until a wheel cylinder went out.

My passenger rear wheel cylinder went out, and both the Brake and ABS warning lights came on. After replacing the wheel cylinder, adjusting the adjuster, and bleeding the brakes, the Brake and ABS lights are still on.

I've tried jabbing the brakes both in drive and reverse, I've bled them again, AND I've tried "resetting" the proportioning valve (described here viewtopic.php?f=45&t=80537&p=761945&hilit=reset+brake+light#p761337).

it brakes perfectly fine. I've checked both the ALDL and ABS computer codes using the paper clip method (my OBDI scanner isn't communicating with it for some reason). The ABS computer flashed code 2 and code 6, but I'm not sure what to do from there.

[AstroWill]

Diagnostic Trouble Codes (DTC) 's can be displayed by jumping terminals "A" and "H" of the Data Link Connector and observing the flashing of the "BRAKE" warning light. This should only be done when the brake lamp is "ON".
The terminals must be jumped for about 20 seconds before the code will begin to flash. Count the number of short flashes starting from the long flash. Include the long flash as a count. Sometimes the first count sequence will be short. However, subsequent flashes will be accurate. If there is more than one failure, only the first recognized code will be retained and flashed.
NOTES:
DTC's 6, 9 and 10 will only turn the "BRAKE" lamp on while the fault exists. These are soft codes faults and can only be read with the Tech 1 scan tool.
Do not jump terminals "A" to "H" if the "BRAKE" lamp is not on. Jumping the terminals with the "BRAKE" lamp off will set a false DTC 9. This will turn the "BRAKE" lamp on and disable the antilock system.
Click the image to open in full size.
1, 11, & 12 ECU Malfunction
2 Open Isolation Valve or Malfunctioning ECU
3 Open Dump Valve or ECU Malfunction
4 Grounded Antilock Valve Reset Switch
5 Eccessive Actuations of the Dump Valve
6 Erratic Speed Signal
7 Shorted Isolation Valve or Faulty ECU
8 Shorted Dump Valve or Faulty ECU
9 Open Circuit to Speed Signal
10 Brake Lamp Switch Circuit
13, 14 and 15 ECU Malfunction


The following is a list of the OBD-I trouble codes for the four wheel anti-lock brake system.

*Code 21: right front speed sensor or circuit open
*Code 22: missing right front speed signal
*Code 23: erratic right front speed signal
*Code 25: left front speed sensor or circuit open
*Code 26: missing left front speed signal
*Code 27: erratic left front speed signal
*Code 29: simultaneous drop-out of front speed sensors
*Code 35: vehicle speed sensor or open circuit
*Code 36: missing vehicle speed sensor signal
*Code 37: erratic vehicle speed sensor signal
*Code 38: wheel speed error
*Codes 41 through 54: control valves
*Codes 61 through 63: reset switches
*Code 65 and 66: open or shorted pump motor relay
*Code 67: open motor circuit or shorted BPMV output
*Code 68: locked motor or shorted motor circuit
*Codes 71 through 74: memory errors
*Code 81: brake switch circuit shorted or open
*Code 86: shorted anti-lock indicator lamp
*Code 87: shorted brake warning lamp

[Dimitri13]

So it seems its either codes 2 and 6, or code 26.

[AstroWill]

Sometimes the first count sequence will be short. However, subsequent flashes will be accurate. If there is more than one failure, only the first recognized code will be retained and flashed.

Does this mean that it's only flashing one code

[karenp]

yes

[Dimitri13]

I got to the LF wheel sensor itself, and it was covered in metal shavings, so I cleaned it off. I bled the brakes for the third time. Then I disconnected the negative battery cable for 15 minutes. ABS and brake lights are still on, but I'm getting either code 36 or 63.

36 is a missing VSS signal. The VSS is the vehicle speed sensor located on the trans, correct? Could it be that my slightly taller tires (215/75-15 instead of 205/75-15) are triggering that?

63 is a reset switch. I have no idea what a reset switch is, aside from it being part of the module's circuitry?

One thing I noticed while bleeding the brakes was that on the combination valve, there were little metal rods on either end of it. While applying the brakes, the rear rod would pop out. Not sure if that's normal or what, because I have no idea what they do.

[tedanderson]

Stupid question but is your electrical connection to the ABS module connected?

[AstroWill]

I got to the LF wheel sensor itself, and it was covered in metal shavings, so I cleaned it off. I bled the brakes for the third time. Then I disconnected the negative battery cable for 15 minutes. ABS and brake lights are still on, but I'm getting either code 36 or 63.

36 is a missing VSS signal. The VSS is the vehicle speed sensor located on the trans, correct? Could it be that my slightly taller tires (215/75-15 instead of 205/75-15) are triggering that?

63 is a reset switch. I have no idea what a reset switch is, aside from it being part of the module's circuitry?

One thing I noticed while bleeding the brakes was that on the combination valve, there were little metal rods on either end of it. While applying the brakes, the rear rod would pop out. Not sure if that's normal or what, because I have no idea what they do.

Glad you got your LF wheel sensor fixed, at least that code is gone. I would think that a code 63 would probably appear even without you moving. I think 36 would appear only after moving where it senses the front wheels moving.

There should be a longer pause between repeating codes, 'should' being the key here.

[Dimitri13]

I drove the van after fixing the first issue. I'm fairly certain it was a code 36. I'll have to go back out an check. But any input on the last part of my last post?

"One thing I noticed while bleeding the brakes was that on the combination valve, there were little metal rods on either end of it. While applying the brakes, the rear rod would pop out. Not sure if that's normal or what, because I have no idea what they do."

[AstroWill]

Sounds like an unbalanced condition, but I would have to double check on that.

[Dimitri13]

Okay so I pulled the van out so I can finally get it registered. I pulled the codes and I'm getting 61, 62, and 63. All "reset switch" codes. I still have no idea what those are. I pulled the ECBM off thinking it was a KH325 unit so I could try resoldering the trouble joints, but it's not. I double checked all the connectors were clean and solid.

Is it possible that air got into the ABS after the rear cylinder leaked out? I bought one of those proportioning valve bleeder tools (the one that goes where the brake light warning switch goes) instead of the ones that go on the ends of the proportioning valve (the ones that look like money clips). Will that do the trick, or do I need the second type?

[Leeann_93]

Completely possible...in fact, probable.

Um, I don't know which clips work better. I have the ones that look like money clips but I've never tried the other ones.


Having said that, I don't know that is your problem. The ABS unit on my '93 Bravada (same unit as on my '93 Astro) had a ton of codes when I got it that were internal faults. I don't remember now what they were, though. I 'fixed' it by grabbing one from a '93 Chevy Blazer Tahoe edition in the junkyard with crossed fingers...and it's still fine. I was pretty careful to get one that had fluid in it and to keep it absolutely upright and still so the fluid was still in it when I got home.