ABS/TRAC/VSC/Brake Light + Warning Tone

[giosue]

Hey Mud,

I had the dreaded ABS/TRAC/VSC/Brake light + warning tone mid-commute the other day. The brakes continued to function as normal, and the lights and tone intermittently turned off. Since then, I've had the car parked because I don't want to risk a sudden complete brake failure. I've started it up a couple times to see if the problem repeats itself, and now, at a complete stop if I pump the brakes twice, the lights will come on and warning tone will sound continuously. They will not come on immediately after starting, only if I press the brake pedal 1-2 times. I've been reading about the pump motor/master cylinder/accumulator failures and am considering my options for OEM vs rebuild, but the reason for posting is because I want to rule out some other electrical problem due to the codes in Techstream below:

2000 LX470 w/ 180k miles
Pump run-time from cold start: 37 seconds
C1223 - ABS Control System Malfunction
C1241 - Low Battery Positive Voltage or Abnormally High Battery Positive Voltage
C1246 - Master Cylinder Pressure Sensor
C1251 - Pump Motor is Locked / Open Circuit in Pump Motor Ground
C1268 - L4 Signal Pickup

Based on the C1241 code, I wanted to rule out a battery issue causing low voltage to the pump motor or something, and because the previous owner had been running a 4 year old 24RVDC battery, I reverted to an OEM 27F battery and disconnected all auxillary items. I also noticed that the battery to chassis ground cable was almost completely torn, so I upgraded that to a thicker gauge ground.

After clearing all codes and retrying after the above repairs/replacements, the lights and warning tone again came on after 1-2 pumps of the pedal and would intermittently turn off for a few seconds as I could hear the pump motor whirring for 1-2 seconds at a time, but then they would stay on persistently. Another look into Techstream yielded the following codes only:

C1223 - ABS Control System Malfunction
C1251 - Pump Motor is Locked / Open Circuit in Pump Motor Ground

At this point it seems like I'm looking at a new pump/accumulator combo vs a rebuild from Andy Le vs part of me wants to spend a few hundred extra dollars to drop in an entire new assembly and never think about it again, but that also seems like burning money that I do not have.

Any other thoughts from you folks before I shell out some money?

Thanks,
Josh

 

[unatiq]

Hey Mud,

I had the dreaded ABS/TRAC/VSC/Brake light + warning tone mid-commute the other day. The brakes continued to function as normal, and the lights and tone intermittently turned off. Since then, I've had the car parked because I don't want to risk a sudden complete brake failure. I've started it up a couple times to see if the problem repeats itself, and now, at a complete stop if I pump the brakes twice, the lights will come on and warning tone will sound continuously. They will not come on immediately after starting, only if I press the brake pedal 1-2 times. I've been reading about the pump motor/master cylinder/accumulator failures and am considering my options for OEM vs rebuild, but the reason for posting is because I want to rule out some other electrical problem due to the codes in Techstream below:

2000 LX470 w/ 180k miles
Pump run-time from cold start: 37 seconds
C1223 - ABS Control System Malfunction
C1241 - Low Battery Positive Voltage or Abnormally High Battery Positive Voltage
C1246 - Master Cylinder Pressure Sensor
C1251 - Pump Motor is Locked / Open Circuit in Pump Motor Ground
C1268 - L4 Signal Pickup

Based on the C1241 code, I wanted to rule out a battery issue causing low voltage to the pump motor or something, and because the previous owner had been running a 4 year old 24RVDC battery, I reverted to an OEM 27F battery and disconnected all auxillary items. I also noticed that the battery to chassis ground cable was almost completely torn, so I upgraded that to a thicker gauge ground.

After clearing all codes and retrying after the above repairs/replacements, the lights and warning tone again came on after 1-2 pumps of the pedal and would intermittently turn off for a few seconds as I could hear the pump motor whirring for 1-2 seconds at a time, but then they would stay on persistently. Another look into Techstream yielded the following codes only:

C1223 - ABS Control System Malfunction
C1251 - Pump Motor is Locked / Open Circuit in Pump Motor Ground

At this point it seems like I'm looking at a new pump/accumulator combo vs a rebuild from Andy Le vs part of me wants to spend a few hundred extra dollars to drop in an entire new assembly and never think about it again, but that also seems like burning money that I do not have.

Any other thoughts from you folks before I shell out some money?

Thanks,
Josh

Odd timing. I just posted something very similar lol.

I have no codes when I check. My noise doesn’t come on when I pump the brakes.

I’m leaning towards just replacing the cylinder.

 

[giosue]

Odd timing. I just posted something very similar lol.

I have no codes when I check. My noise doesn’t come on when I pump the brakes.

I’m leaning towards just replacing the cylinder.

No codes in Techstream? Or no codes on one of those handheld OBD scanners?

When the lights and noise flicked on for me my little scanner I keep in my car did not show any codes. I only found them when I looked in Techstream.

 

[squidmotion]

No codes in Techstream? Or no codes on one of those handheld OBD scanners?

When the lights and noise flicked on for me my little scanner I keep in my car did not show any codes. I only found them when I looked in Techstream.

I’ll add to this my experience recently.

I was having the brake light/ABS light combo with the alarm after cranking up in the morning. I couldn’t get a code until i connected up my newer reader, while the vehicle was running, and the warning lights on. As it seems, most early OBD will clear the brake codes after the vehicle is turned off. Catching the code with my most robust, newer reader, as the vehicle displayed the brake/ABS light was the key.. I repeated this with my BlueDriver setup as well, which showed the code as well. The old OBD reader i’ve had for years didn’t allow me to read any brake/ABS codes.

I had the dreaded C1251 code.. replaced the MC/booster assembly, and all is right.

It pays to be able to get the trouble code for your issue. I was hoping for a bad wheel sensor, but not in the cards.

I hope this helps anyone trying to diagnose brake/ABS light issues.