Tutorial LS460: Clear “Brake Malfunction, Check VSC System” Dash Error Messages
Thread Starter
Intermediate
Joined: Sep 2017
Posts: 413
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From: California
I should have provided more information. I've been trying to determine if I need to replace my brake accumulator on my 2007 LS460. This started when I replaced my front calipers - when doing so I disconnected the battery and clamped the brake fluid hoses at the calipers to avoid any indication to the computer that anything had happened while the battery was disconnected. That didn't work - when I started the car up I had all the lights on the instrument panel discussed above. My initial step was to first bleed the brakes. I used the Techstream directions but I did not run the "Zero Down" procedure. Bleeding the brakes seemed to go fine but when I ran the linear valve offset (after clearing the memory) I still had the lights. So, I attempted to perform the brake bleed under the "replaced accumulator" procedure. For some reason I could not get past bleeding the accumulator through the rear right bleeder. The error message was that the bleed had failed ( I don't remember the exact message) As I was about to quit for the night I decided to try the linear valve offset (again after clearing the memory) and all but one of the error codes were cleared. At that point the brakes worked very well and the dash error lights were all gone. The next morning when I started the car the lights were all back. I ran the linear valve offset again and the error codes were gone but they came back within a minute of driving. Is my failure to do the zero down procedure perhaps the reason I can't keep the codes cleared or could it be a bad accumulator? I don't think the problem is the pump because when bleeding the rear brakes the brake fluid did stream out.
I've successfully run the linear valve offset a number of times in the past when working on the brakes but this time the codes simply won't stay away.
I've successfully run the linear valve offset a number of times in the past when working on the brakes but this time the codes simply won't stay away.
The background information is helpful for understanding your brake issue. From your description of what happened, it seems that you didn't do a zero down (releasing the pump pressure) before you took off the brake calipers to replace them. I assume that you didn't wait for the calipers to be filled up with brake fluid before you reconnected the battery. The brake ECU sensed that there was a lot of loss of brake fluid and triggered the trouble code. Since you were able to clear the brake ECU memory and successfully run the linear valve offset calibration, it seems that your brake accumulator is still good. Somehow there is (a lot of) air in the brake system, which keeps causing trouble code. My recommendation is that you thoroughly bleed the brake system with the brake accumulator replacement procedure. Stick to Lexus shop brake bleeding procedure and don't omit any steps in the bleeding process. I think that after you throughly bleed the brake system with the brake accumulator replacement procedure (which bleeds the accumulator as well as brake lines), your brake system should be restored. By the way, below is the normal procedure for replacing brake calipers, in case you need to replace the brake calipers again:
(1) zero down (release pump pressure) with Techstream
(2) turn off the ignition
(3) disconnect the two power connectors to the brake pump (to avoid accidentally sending trouble signals to brake ECU)
(4) turn on the ignition (not to start the engine)
(5) do a brake ECB Invalid with Techstream
(6) turn off the ignition
(7) disconnect the negative terminal from the battery
(8) begin to replace brake calipers
After you have replaced the brake calipers, let the brake fluid flow down naturally by gravity through the brake hose to fill the brake calipers (keep an eye on the level of fluid in the brake fluid reservoir as add fluid as needed so that the brake fluid won't be lower than the Minimum Level line). When the brake fluid begins to dripping down out of the brake bleeder, tighten the bleeder. Connect the battery and begin the brake bleeding process. Because there is no significant loss of fluid in the brake system, there is no trigger for the brake ECU to panic and throw the trouble codes.
Pit Crew
Joined: May 2005
Posts: 128
Likes: 3
From: Nevada
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The background information is helpful for understanding your brake issue. From your description of what happened, it seems that you didn't do a zero down (releasing the pump pressure) before you took off the brake calipers to replace them. I assume that you didn't wait for the calipers to be filled up with brake fluid before you reconnected the battery. The brake ECU sensed that there was a lot of loss of brake fluid and triggered the trouble code. Since you were able to clear the brake ECU memory and successfully run the linear valve offset calibration, it seems that your brake accumulator is still good. Somehow there is (a lot of) air in the brake system, which keeps causing trouble code. My recommendation is that you thoroughly bleed the brake system with the brake accumulator replacement procedure. Stick to Lexus shop brake bleeding procedure and don't omit any steps in the bleeding process. I think that after you throughly bleed the brake system with the brake accumulator replacement procedure (which bleeds the accumulator as well as brake lines), your brake system should be restored. By the way, below is the normal procedure for replacing brake calipers, in case you need to replace the brake calipers again:
(1) zero down (release pump pressure) with Techstream
(2) turn off the ignition
(3) disconnect the two power connectors to the brake pump (to avoid accidentally sending trouble signals to brake ECU)
(4) turn on the ignition (not to start the engine)
(5) do a brake ECB Invalid with Techstream
(6) turn off the ignition
(7) disconnect the negative terminal from the battery
(8) begin to replace brake calipers
After you have replaced the brake calipers, let the brake fluid flow down naturally by gravity through the brake hose to fill the brake calipers (keep an eye on the level of fluid in the brake fluid reservoir as add fluid as needed so that the brake fluid won't be lower than the Minimum Level line). When the brake fluid begins to dripping down out of the brake bleeder, tighten the bleeder. Connect the battery and begin the brake bleeding process. Because there is no significant loss of fluid in the brake system, there is no trigger for the brake ECU to panic and throw the trouble codes.
The background information is helpful for understanding your brake issue. From your description of what happened, it seems that you didn't do a zero down (releasing the pump pressure) before you took off the brake calipers to replace them. I assume that you didn't wait for the calipers to be filled up with brake fluid before you reconnected the battery. The brake ECU sensed that there was a lot of loss of brake fluid and triggered the trouble code. Since you were able to clear the brake ECU memory and successfully run the linear valve offset calibration, it seems that your brake accumulator is still good. Somehow there is (a lot of) air in the brake system, which keeps causing trouble code. My recommendation is that you thoroughly bleed the brake system with the brake accumulator replacement procedure. Stick to Lexus shop brake bleeding procedure and don't omit any steps in the bleeding process. I think that after you throughly bleed the brake system with the brake accumulator replacement procedure (which bleeds the accumulator as well as brake lines), your brake system should be restored. By the way, below is the normal procedure for replacing brake calipers, in case you need to replace the brake calipers again:
(1) zero down (release pump pressure) with Techstream
(2) turn off the ignition
(3) disconnect the two power connectors to the brake pump (to avoid accidentally sending trouble signals to brake ECU)
(4) turn on the ignition (not to start the engine)
(5) do a brake ECB Invalid with Techstream
(6) turn off the ignition
(7) disconnect the negative terminal from the battery
(8) begin to replace brake calipers
After you have replaced the brake calipers, let the brake fluid flow down naturally by gravity through the brake hose to fill the brake calipers (keep an eye on the level of fluid in the brake fluid reservoir as add fluid as needed so that the brake fluid won't be lower than the Minimum Level line). When the brake fluid begins to dripping down out of the brake bleeder, tighten the bleeder. Connect the battery and begin the brake bleeding process. Because there is no significant loss of fluid in the brake system, there is no trigger for the brake ECU to panic and throw the trouble codes.
Thread Starter
Intermediate
Joined: Sep 2017
Posts: 413
Likes: 257
From: California
Zero Down first. Then disconnect the two accumulator power connectors (near the firewall on the driver side) before you run the ECB Invalid. The best way to do it is to follow the instruction on Techstream screen after you have selected brake bleeding with accumulator replaced. The instruction on Techstream is logic and procedural. Just do exactly as Techstream instructs you to do, step by step. Make sure that your car battery is fully charged because the brake bleeding procedure consumes a lot of power. In fact, Lexus shop manual advises that a power charger is connected to the battery while doing the brake bleed procedure to avoid a power failure in the middle brake bleeding.
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Pit Crew
Joined: May 2005
Posts: 128
Likes: 3
From: Nevada
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Zero Down first. Then disconnect the two accumulator power connectors (near the firewall on the driver side) before you run the ECB Invalid. The best way to do it is to follow the instruction on Techstream screen after you have selected brake bleeding with accumulator replaced. The instruction on Techstream is logic and procedural. Just do exactly as Techstream instructs you to do, step by step. Make sure that your car battery is fully charged because the brake bleeding procedure consumes a lot of power. In fact, Lexus shop manual advises that a power charger is connected to the battery while doing the brake bleed procedure to avoid a power failure in the middle brake bleeding.
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Zero Down first. Then disconnect the two accumulator power connectors (near the firewall on the driver side) before you run the ECB Invalid. The best way to do it is to follow the instruction on Techstream screen after you have selected brake bleeding with accumulator replaced. The instruction on Techstream is logic and procedural. Just do exactly as Techstream instructs you to do, step by step. Make sure that your car battery is fully charged because the brake bleeding procedure consumes a lot of power. In fact, Lexus shop manual advises that a power charger is connected to the battery while doing the brake bleed procedure to avoid a power failure in the middle brake bleeding.
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Pit Crew
Joined: May 2005
Posts: 128
Likes: 3
From: Nevada
------
Zero Down first. Then disconnect the two accumulator power connectors (near the firewall on the driver side) before you run the ECB Invalid. The best way to do it is to follow the instruction on Techstream screen after you have selected brake bleeding with accumulator replaced. The instruction on Techstream is logic and procedural. Just do exactly as Techstream instructs you to do, step by step. Make sure that your car battery is fully charged because the brake bleeding procedure consumes a lot of power. In fact, Lexus shop manual advises that a power charger is connected to the battery while doing the brake bleed procedure to avoid a power failure in the middle brake bleeding.
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Zero Down first. Then disconnect the two accumulator power connectors (near the firewall on the driver side) before you run the ECB Invalid. The best way to do it is to follow the instruction on Techstream screen after you have selected brake bleeding with accumulator replaced. The instruction on Techstream is logic and procedural. Just do exactly as Techstream instructs you to do, step by step. Make sure that your car battery is fully charged because the brake bleeding procedure consumes a lot of power. In fact, Lexus shop manual advises that a power charger is connected to the battery while doing the brake bleed procedure to avoid a power failure in the middle brake bleeding.
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Last edited by CPALex; Dec 26, 2020 at 08:20 PM. Reason: mistake
Thread Starter
Intermediate
Joined: Sep 2017
Posts: 413
Likes: 257
From: California
Sorry to hear that a full brake bleed didn't solve the problem. C1253 indicates several possibilities, including pump motor relay. It could also be caused by a faulty ABS sensor (https://www.clublexus.com/forums/ls-...problem-2.html) or worse, as you suspected, a faulty actuator. Additionally, since LS460 is sensitive to the battery capacity level, what is the condition of your car battery (try to rule out the simple possible causes first)? How did your full brake bleeding (with actuator replaced procedure) go? Did it go smoothly or did you experience any issues? If you ran out of ideas, maybe it is time to have Lexus diagnose the cause of the problem. After Lexus dealer figures out what is the cause of the problem, you could buy the part and do the repair work by yourself.
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Thread Starter
Intermediate
Joined: Sep 2017
Posts: 413
Likes: 257
From: California
How to Clear C1256 and C1345 codes
*** How to Clear C1256 and C1345 codes ***
Bleeding LS460 brakes with Techstream drains the car's battery quickly. The brake bleeding with Techstream requires a constant power supply of approximately 31 amps throughout the bleeding process. Unless your battery is brand new and can hold almost a full charge, if you do a full brake bleeding procedure with Techstream without connecting a good battery charger or 12V converter, your battery level will run low and you will almost certainly get stranded in the last few steps of the brake bleeding, either you are doing an "Usual air bleeding" procedure or an "Actuator has been removed" bleeding procedure. Typically, you can't complete "Linear Valve Offset" because of a low battery level, triggering Trouble Codes C1256 (accumulator low pressure) and C1345 (Linear Solenoid Valve Offset Undone). When you talk with an inexperienced Lexus dealer technician or an inexperienced indy shop technician about having code C1345, typically they will want to replace the accumulator assembly, which will solve the problem because they will have to do an "Actuator has been removed" bleeding procedure with the new brake accumulator. However, the truth of the matter is that the accumulator assembly is fine. It's just that the brake pump is instructed by the brake ECU not to pressurize air, thinking that you are still in the middle of offsetting the linear solenoids. However, when you attempt to re-do the linear solenoid valve offset procedure, the brake ECU also prevents you from doing it because the brake pump cannot pressurize air. It's a good example of Catch-22. The best prevention of triggering code C1345 and C1256 is to have a good charger or 12V converter hooked up to your battery BEFORE you begin the brake bleeding procedure to ensure that the power supply is good throughout the brake bleeding procedure. If you somehow unfortunately end up with C1345 and C1256 codes during brake bleeding with Techstream as I did today (I was a bit careless when I did my 30K-mile brake fluid replacement today), the solution is actually fairly simple. Just re-run the full "Actuator has been removed" bleeding procedure step by step with a good battery charger/converter connected to your battery. If you have already bled the brakes, you just need to dry-run the "Actuator has been removed" bleeding procedure without having to replace your fresh brake fluid in the brake system again. After you have dry-run the "Actuator has been removed" bleeding procedure, you will be able to reset the brake memory and complete the linear solenoid valve offset. All will be good. There is no need to replace your brake accumulator. Big thanks to hardtopte7 who shared his dilemma and how he resolved Codes C1256 and C1345 in Posting #61.
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Bleeding LS460 brakes with Techstream drains the car's battery quickly. The brake bleeding with Techstream requires a constant power supply of approximately 31 amps throughout the bleeding process. Unless your battery is brand new and can hold almost a full charge, if you do a full brake bleeding procedure with Techstream without connecting a good battery charger or 12V converter, your battery level will run low and you will almost certainly get stranded in the last few steps of the brake bleeding, either you are doing an "Usual air bleeding" procedure or an "Actuator has been removed" bleeding procedure. Typically, you can't complete "Linear Valve Offset" because of a low battery level, triggering Trouble Codes C1256 (accumulator low pressure) and C1345 (Linear Solenoid Valve Offset Undone). When you talk with an inexperienced Lexus dealer technician or an inexperienced indy shop technician about having code C1345, typically they will want to replace the accumulator assembly, which will solve the problem because they will have to do an "Actuator has been removed" bleeding procedure with the new brake accumulator. However, the truth of the matter is that the accumulator assembly is fine. It's just that the brake pump is instructed by the brake ECU not to pressurize air, thinking that you are still in the middle of offsetting the linear solenoids. However, when you attempt to re-do the linear solenoid valve offset procedure, the brake ECU also prevents you from doing it because the brake pump cannot pressurize air. It's a good example of Catch-22. The best prevention of triggering code C1345 and C1256 is to have a good charger or 12V converter hooked up to your battery BEFORE you begin the brake bleeding procedure to ensure that the power supply is good throughout the brake bleeding procedure. If you somehow unfortunately end up with C1345 and C1256 codes during brake bleeding with Techstream as I did today (I was a bit careless when I did my 30K-mile brake fluid replacement today), the solution is actually fairly simple. Just re-run the full "Actuator has been removed" bleeding procedure step by step with a good battery charger/converter connected to your battery. If you have already bled the brakes, you just need to dry-run the "Actuator has been removed" bleeding procedure without having to replace your fresh brake fluid in the brake system again. After you have dry-run the "Actuator has been removed" bleeding procedure, you will be able to reset the brake memory and complete the linear solenoid valve offset. All will be good. There is no need to replace your brake accumulator. Big thanks to hardtopte7 who shared his dilemma and how he resolved Codes C1256 and C1345 in Posting #61.
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Last edited by yyymmm31; Jan 20, 2021 at 12:14 PM. Reason: corrected a typo
Driver
Joined: Dec 2020
Posts: 95
Likes: 6
From: UAE
My VSC light, engine and traction light came back on. My reliable and informed shop technician connected the computer to it and it came up with 3 cat converter issues. He said it would require a process of elimination, starting with sensors, if this doesn't work then the cats at the manifold.
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Joined: Nov 2020
Posts: 8
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From: Colorado
I have what I suspect is a bad actuator. I have no codes and no error messages, however, I hear the pump prime when I press hard on the brakes. Also, I don't have any of the squawk or pulsation symptoms described by others with bad Actuators. Could this be a symptom of air in the line or should suspect that my actuator is bad? Which of the above process' is best to bleed the system to test the theory of air in the line?
Thread Starter
Intermediate
Joined: Sep 2017
Posts: 413
Likes: 257
From: California
I have what I suspect is a bad actuator. I have no codes and no error messages, however, I hear the pump prime when I press hard on the brakes. Also, I don't have any of the squawk or pulsation symptoms described by others with bad Actuators. Could this be a symptom of air in the line or should suspect that my actuator is bad? Which of the above process' is best to bleed the system to test the theory of air in the line?
It could be a degrading brake actuator. However, if you haven't bled the brake system for more than 3 years or 30K miles, it's most likely that there is some air in the brake system that causes the brake pump to pressurize air when you press the brake pedal hard. I'd suggest that you do a "Usual air bleeding" with Techstream (in Techstream, go to ABS/VSC/TRAC => Air Bleeding => Usual air bleeding). Follow the instruction on Techstream screens step by step to complete the bleeding procedure. The "Usual air bleeding" procedure should eliminate the air in your brake system and restore your brake's effectiveness. Important note: have your battery fully charged and attach a good charger or 12V converter to your battery before bleeding the brake with Techstream to avoid getting stranded in the middle of bleeding because of an exhausted battery.
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Driver School Candidate
Joined: Nov 2020
Posts: 8
Likes: 3
From: Colorado
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It could be a degrading brake actuator. However, if you haven't bled the brake system for more than 3 years or 30K miles, it's most likely that there is some air in the brake system that causes the brake pump to pressurize air when you press the brake pedal hard. I'd suggest that you do a "Usual air bleeding" with Techstream (in Techstream, go to ABS/VSC/TRAC => Air Bleeding => Usual air bleeding). Follow the instruction on Techstream screens step by step to complete the bleeding procedure. The "Usual air bleeding" procedure should eliminate the air in your brake system and restore your brake's effectiveness. Important note: have your battery fully charged and attach a good charger or 12V converter to your battery before bleeding the brake with Techstream to avoid getting stranded in the middle of bleeding because of an exhausted battery.
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It could be a degrading brake actuator. However, if you haven't bled the brake system for more than 3 years or 30K miles, it's most likely that there is some air in the brake system that causes the brake pump to pressurize air when you press the brake pedal hard. I'd suggest that you do a "Usual air bleeding" with Techstream (in Techstream, go to ABS/VSC/TRAC => Air Bleeding => Usual air bleeding). Follow the instruction on Techstream screens step by step to complete the bleeding procedure. The "Usual air bleeding" procedure should eliminate the air in your brake system and restore your brake's effectiveness. Important note: have your battery fully charged and attach a good charger or 12V converter to your battery before bleeding the brake with Techstream to avoid getting stranded in the middle of bleeding because of an exhausted battery.
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Thread Starter
Intermediate
Joined: Sep 2017
Posts: 413
Likes: 257
From: California
Hi, macLexy55. Sorry that I didn't realize that you were asking me the question. The tutorial (my first posting of the thread) is for resolving brake lockup issues caused by brake service/maintenance operations, in which the dashboard flashes with a specific message related to brake system: "Check your brake system" and there are associated brake-related trouble codes if you check the brake system with Techtream or other code readers. In your case, when you have a flashing dash message not related to the brake system and that the trouble codes are not associated with the brake system, your car problems are not related to the brake system. Therefore, this tutorial and the subsequent information and solutions posted in this thread cannot help you. In other words, you need to find the solutions based on your car's trouble codes.
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