Brakes ...... Overdue write-up. (2 Viewers)

[Octous]

On 8/28/2024 fully flushed brake system per instructions from @2001LC.

Got an intermittent ABS light and buzz while driving around the neighborhood on two test drives on two conssecutive days. This was possibly due to:
1. low battery voltage (I had some new lights that did a constant parasitic battery drain)
2. washing the engine bay around the ABS unit

Pulled codes found:
1. C1256 - low pressure of accumulator

Looked at live data for ABS unit and found:
1. low ignition voltage to ABS unit

Performed following
1. Charged battery
2. Removed, cleaned and reconnected all electrical connectors on ABS unit
3. Cleared codes
4. No new errors (but live data still showed low ignition voltage to ABS unit)
5. Jumped diagnostic port under hood, ABS light blinked every .25 sec indicating healthy ABS unit
6. timed brake accumulator fill after pumping brake pedal 40 times (34 sec -- within 30-40 sec Toyota spec)
See video: 1999 Land Cruiser Brake Booster · Thursday, Jul 10 ð¸ - https://photos.google.com/share/AF1QipMirFGh-D7Sf9yBbrmp3JdlXrpDH3w4nfNQZ93oGXVZCfxiLQ8j2Qv0kpQGpjsIqw?key=QUxaNkxSdEY4YnBENFYzTHAyODhXemRHeGRnR0Rn

I've now been test driving the vehicle for a couple of days and the ABS light, buzzer, code hasn't come back. I'm thinking this was due to an electrical gremlin and not an actual real issue.

I'm hoping this isn't wishful thinking so I'm hoping that @2001LC. Can check my homework .

Going to the Rubicon in two weeks and so am paranoid about everything!

 

[2001LC]

Not sure what "low voltage" in ABS tech stream is or indicating.

When battery voltage drops to low, we'll get these DTC (codes). Provided DTC do not return, booster motor runs every time pressure drops (pump pedal more than a few time, or key off pump 40 times, key off for several hours). You should be good to go.

I'm assuming fluid good, reservoir not stained badly, brake control wire not corroded.

Make sure to check all flexible lines.

 

[Octous]

Thanks for the quick response @2001LC !
I'll see if I can get a screen grab of the low voltage live data error. It was from a 3rd party scan tool (not Tech Stream) so I'm not confident it's real.

Fluid is good
Reservoir is not stained

What is the brake control wire? Do you mean the motor to brake controller connections?

 

[2001LC]

Thanks for the quick response @2001LC !
I'll see if I can get a screen grab of the low voltage live data error. It was from a 3rd party scan tool (not Tech Stream) so I'm not confident it's real.

Fluid is good
Reservoir is not stained

What is the brake control wire? Do you mean the motor to brake controller connections?
View attachment 3947965

Yes!