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The Potential Prius Brake Defect – The History & The Details

2010 PRIUS BRAKE DEFECT

TOYOTA SAFETY RECALL A0B (NHTSA ID 10V-039) 

The A0B Defect Information Report

On February 9, 2010 Toyota launched Safety Recall A0B (NHTSA ID 10V-039) because customers were “perceiving inconsistent brake feel after ABS actuation…” and because Toyota had received field reports indicating “issues with the VSC/brake performance.” Safety Recall A0B covered 133,459 Prius vehicles and 15,090 Lexus HS250H vehicles.

The Defect Information Report - or DIR – sent to the National Highway Traffic Safety Administration was signed and submitted by Toyota’s Manager of Technical and Regulatory Affairs Chris Santucci. Prior to coming on board with Toyota, Mr. Santucci had been employed as a Defect Investigator at the National Highway Traffic Safety Administration.

The Defect Information Report states that Toyota launched a safety recall despite the fact that, “…the ABS is operating as designed".

Toyota represented the cure would be, “a rewrite of the programming of the ABS control unit.”

Confusingly, in later documentation addressing defects or potential defects in the Prius braking system Toyota refers to the ABS control unit using many different names such as the “ABS Actuator ECU,” the “ABS Actuator Skid Control Electronic Control Unit,” and the “Skid Control ECU.”

 

Unique Characteristics of NHTSA's Preliminary Evaluation

On February 3, 2010 the National Highway Traffic Safety Administration opened Preliminary Evaluation PE10-006 on 2010 Prius vehicles because, “The Office of Defects Investigation (ODI) has received 124 reports from consumers alleging a momentary reduction in braking performance…Four of these reports allege crashes occurred. Two of these reports allege 2 minor injuries occurred as a result of these crashes.”

Typically, when NHTSA opens a Preliminary Evaluation they request wide-ranging information such as the manufacturer’s customer complaints, field reports, crash reports, fatality reports, arbitrations, warranty claims, repair dates, and additional information to assess the danger of the potential safety defect. When a manufacturer responds with the information NHTSA’s has historically made it publicly available on the safercar.gov website.

In the case of the NHTSA’s Preliminary Evaluation PE10-006 regarding brake defects in the 2010 Prius, Toyota’s response data is not publicly available through NHTSA’s safercar.gov website.

There is one email chain between Toyota’s Manager of Technical and Regulatory Affairs Chris Santucci, who was previously employed as a Defect Investigator at NHTSA, and the Chief of the Vehicle Integrity Division of the US Department of Transportation D. Scott Yon.

In the chain, Mr. Yon requests information for the Preliminary Evaluation of the Prius’ brake defect - including consumer complaints, field reports, crash incidents, injury incidents, fatality incidents, and warranty claims – be submitted by June 18, 2010. Mr. Santucci indicates that, “there was a larger volume of information for Toyota to review than originally estimated…” and is granted an extension on the due date.

Today, the important requested data pertaining to the brake defect in 2010 Toyota Prius vehicles is not publicly available on NHTSA’s safercar.gov website.

***Toyota's response data to NHTSA's Preliminary Evaluation has been requested from NHTSA via the Freedom of Information Act website.

 

The Chronology of the A0B Defect Information Report

In the Chronology of Principle Events section of the DIR for Toyota’s A0B safety recall Mr. Santucci represents that between October 2009 and January 2010 “Toyota received another field technical report from the U.S. market which indicated issues with the VSC/brake performance.” Below are two examples of complaints from NHTSA’s safercar.gov website demonstrating “issues with the VSC/brake performance” were occurring in 2010 Prius prior to October 2009.

February 4, 2010 NHTSA ID NUMBER: 10305572

Components: SERVICE BRAKES, HYDRAULIC

NHTSA ID Number: 10305572

Incident Date August 20, 2009

Consumer Location ROCKVILLE CENTRE, NY

Vehicle Identification Number JTDKN3DU3A1****

Summary of Complaint

CRASHNo

FIRENo

INJURIES0

DEATHS0

MY PRIUS LOSES ITS BRAKING ABILITY WHEN I HIT A POTHOLE OR IF I DRIVE OVER A SEWER GRATE. I'VE OWNED THE CAR SINCE JULY 2009, IT IS A 2010 MODEL. IT ALSO HAPPENS WHEN I DRIVE OVER BUMPS IN THE ROAD. THIS HAS HAPPENED SEVERAL TIMES SINCE JULY. IT SEEMS TO HAPPEN MORE IN WET WEATHER. *TR

February 4, 2010 NHTSA ID NUMBER: 10305159

Components: SERVICE BRAKES, HYDRAULIC

 

NHTSA ID Number: 10305159

Incident Date August 13, 2009

Consumer Location BALTIMORE, MD

Vehicle Identification Number JTDKN3DU8A0****

Summary of Complaint

CRASHNo

FIRENo

INJURIES0

DEATHS0

I PURCHASED MY 2010 PRIUS ON AUGUST 4TH, 2009 AND ALMOST IMMEDIATELY NOTICED ISSUES WITH THE BRAKES. I DISTINCTLY REMEMBER DRIVING IN THE CAR ON THIS DATE WITH MY WIFE AS WE WERE ON OUR WAY BACK FROM HER ULTRASOUND. I JUST GOT OFF THE HIGHWAY AND THERE WAS A RED LIGHT AHEAD WITH SEVERAL CARS STOPPED AT IT. I APPLIED THE BRAKES SLOWLY AND STEADILY, AS I NORMALLY DO, BRAKING WITH PLENTY OF TIME TO STOP. AS I APPROACHED THE LAST CAR AT THE STOP LIGHT I ENCOUNTERED A POT HOLE AND THE BRAKES DISENGAGED. I COULD FEEL THE CAR WAS NO LONGER DECELERATING. I HAD TO SLAM ON THE BRAKES AND BARELY AVOIDED SLAMMING IN TO THE CAR AHEAD OF ME, STOPPING WITH LITERALLY AN INCH BETWEEN OUR BUMPERS. SINCE THAT DATE I HAVE ENCOUNTERED THIS EXACT SAME SCENARIO SEVERAL TIMES A MONTH AND HAVE COME CLOSE TO AN ACCIDENT 2 TO 3 TIMES. *TR

Because Toyota’s responses to NHTSA’s Preliminary Evaluation information requests are not currently publicly available on the safercar.gov website, Toyota’s accuracy regarding dates of complaints or incidents of the brake defect “indicating issues with the VSC/brake performance” prior to October 2009 has not be verified.

 

Omission of a Potential Safety-Related Part Design Change

Despite the fact that former NHTSA defect investigator Chris Santucci represented that the A0B safety recall was being launched to address “issues with the VSC/brake performance” in certain Prius vehicles, the defect information report fails to disclose that in September 2009 Toyota began utilizing an “updated brake accumulator” during 2010 Prius production.

The brake accumulator is an integral component regarding the “the VSC/brake performance” in affected Prius vehicles. Toyota would disclose this production countermeasure in a Defect Information Report filed for safety recall D0H (NHTSA ID 13V-235) launched in June 2013.

As explained in Toyota’s Deferred Prosecution Agreement with the US Department of Justice, in which Toyota pled guilty to wire fraud for their illegal conduct during the Unintended Acceleration Scandal, “Although Toyota is not required to notify NHTSA of any engineering and design changes it made to Toyota and Lexus models sold in the United States, it is required to file a DIR for any safety-related defect addressed by such an engineering and/or design change.”

Here is another excerpt regarding part design improvements from Toyota's Deferred Prosecution Agreement:

The “Chronology of Principle Events” section of the defect information report for Toyota’s A0B safety recall reflects that Toyota conducted an approximately 7 month long investigation into the Prius brake defect. This section does not make any mention of the brake accumulator being considered as a cause of the safety defect in the Prius brakes.

Additionally, question #8 of Toyota’s “Q&A” documentation for the A0B safety recall asks, “Have any production changes been implemented?” The answer only discloses a change made to the ABS Actuator ECU in January 2010. The accumulator update from September 2009 is not mentioned.

Toyota would later conduct a safety recall on the Brake Booster Pump in certain 2010 Prius under its D0H campaign  and would also later cover the Brake Booster Assembly (also referred to by Toyota as the Brake Master Cylinder Assembly) and Brake Booster Pump Assemblies of certain 2010 Prius under Warranty Enhancement ZJB.

Toyota’s representations of low-cost software updates as remedies for safety defects have recently been called into question.

 

Toyota Stops Providing VIN Specific Safety Recall Lists to Dealers

In the “Dealer Summary Reports” section of its dealer letter for the A0B safety recall, Toyota states, “VIN lists of vehicles in the dealership’s PMA will no longer be provided.” The term “PMA” stands for Primary Market Area.

According to the federally-appointed monitor for the Takata Airbag safety recall, providing this VIN specific data to local dealerships so that they can reach out to their customer base is critical to increasing safety recall completion rates.

Dealer Letters for the more recent J0T Toyota Prius Safety Recall indicates that in many cases Toyota still does not provide its dealers with “VIN lists of vehicles in the dealership’s PMA…” that have the safety recall outstanding.

Technical Service Bulletin 0363-10

In December 2010 Toyota issued technical service bulletin 0363-10 covering “some 2010 Prius and early produced 2011 Prius vehicles which may exhibit an abnormal noise when the brake pedal is released.”

If a customer complained about this particular noise Toyota would authorize installation of “revised” calibration software for the “ABS Actuator Skid Control Electronic Control Unit.”

This is the same component that received a software update as the “remedy” to Toyota’s A0B Safety Recall. The A0B safety recall covered only some 2010 Prius vehicles and did not cover any 2011 Prius vehicles.

Toyota’s technical instructions for the A0B safety recall state that the ID number of the “remedy” software is F152647106 for Prius vehicles with 15 inch wheels and F152647126 for Prius vehicles with 17 inch wheels.

TSB 0363-10 states the updated software ID number is F152647108 for Prius vehicles with 15 inch wheels or F152647128 for Prius vehicles with 17 inch wheels.

An A0B “remedy” software update for the ABS control unit was superseded by an updated version at a later date.

 

SAFETY RECALL D0H (NHTSA ID 13V-235)

The D0H Defect Information Report

On June 5, 2013 Toyota Motor Engineering & Manufacturing North America, Inc.’s Vice President, Abbas Saadat, submitted a Defect Information Report to the National Highway Traffic and Safety Administration for Toyota’s D0H safety recall (NHTSA ID 13V-235).

Toyota’s D0H safety recall addressed a defect in Brake Booster Pump Assemblies manufactured by Japan’s Advics Co., LTD.

Inside the brake booster pump assembly is the brake pressure accumulator. Toyota’s D0H defect information report states, “There is a possibility that a fatigue crack could develop…” on a component of the accumulator. It continues to state this could, “cause the brake pedal stroke to become longer, resulting in decreased hydraulic pressure” which could “affect stopping distance and increase the risk of a crash.”

The “Chronology of Principle Events” section of the DIR shows Toyota conducted an approximately 3 year investigation before announcing safety recall D0H.

Toyota’s “remedy” called for an “inspection” of the brake booster pump assembly and its replacement if it was deemed “affected.”

 

Reduction in the Number of Covered 2010 Prius

Toyota’s D0H safety recall covers approximately 82,000 model year 2010 Prius vehicles and approximately 5,100 model year 2010 Lexus HS250h vehicles. Approximately 45,000 fewer 2010 Prius vehicles are covered by Toyota’s D0H safety recall than by Toyota’s A0B safety recall.

There are many complaints from Prius owners inquiring as to why their vehicle was excluded from the covered population yet it experienced a similar condition as described by Toyota’s D0H Safety Recall.

March 21, 2018 NHTSA ID NUMBER: 11080403

Components: SERVICE BRAKES

NHTSA ID Number: 11080403

Incident Date March 19, 2018

Consumer Location HOUSTON, TX

Vehicle Identification Number JTDKN3DU3B1****

Summary of Complaint

CRASHNo

FIRENo

INJURIES0

DEATHS0

I WAS DRIVING AT ABOUT 35 MPH AND ALL OF A SUDDEN MY BRAKES STOPPED WORKING. THE BRAKE , ABS AND TRACTION LIGHTS CAME ON ALL AT ONCE. I SOMEHOW MADE IT HOME BUT I COULD HAVE EASILY CRASHED. I HAD MY 9 YEAR OLD IN THE BACK SEAT AND HE ALSO GOT VERY SCARED. NOW I CANNOT DRIVE MY CAR AND THE BRAKES FEEL AS THEY AS STUCK AND VERY HARD. I TOOK MY CAR TO A REPUTABLE MECHANIC AND HE TOLD ME IT IS GIVING HIM CODE C1391. THIS IS THE SAME PROBLEM THAT THE 2010 PRIUS HAD UNDER THE RECALL. MY PRIUS IS 2011 AND NOT UNDER THE RECALL. I FEEL THAT THE 2011 SHOULD BE UNDER RECALL BECAUSE MANY THOUSANDS OF LIVES ARE IN DANGER NOW.

1 Affected Product 

Request Research (Services fees apply)

January 10, 2018 NHTSA ID NUMBER: 11061959

Components: SERVICE BRAKES

NHTSA ID Number: 11061959

Incident Date January 9, 2018

Consumer Location CORPUS CHRISTI, TX

Vehicle Identification Number JTDKN3DU5B5****

Summary of Complaint

CRASHNo

FIRENo

INJURIES0

DEATHS0

I WAS AT AN AUTOMATIC CAR WASH YESTERDAY AND AFTER THE WASH FINISHED I PULLED OUT OF STALL WITH HARDLY ANY BRAKES.I WAS NOT ABLE TO PUMP THEM AND HAD TO TAKE MY CAR INTO A MECHANIC THE BRAKE ACTUATOR WAS OUT AND THE CAR IS UNDRIVABLE.THE PRICE FOR THE PART ALONE IS OVER 2500.00 I WAS INFORMED BY THE DEALERSHIP THAT IS WAS A RECALLED ITEM BUT NOT FOR THE YR OF MY CAR. IF THIS WOULD HAVE HAPPENED IN TRAFFIC OR AT A HIGH RATE OF SPEED I KNOW I WOULD HAVE BEEN IN A SERIOUS ACCIDENT AND I COULD HAVE KILLED SOMEONE.

1 Affected Product 

Request Research (Services fees apply)

 

The "Inspection Only" Population Included in the D0H Safety Recall

The “Description of Corrective Repair Action” section of Toyota’s defect information report for safety recall D0H states that, “The dealer will inspect the brake booster pump assembly, and, if it is equipped with an affected accumulator, the dealer will replace the brake booster pump assembly with an improved one.”

According to Toyota’s technical instructions all this “inspection” to identify is a Prius is equipped with an affected accumulator requires is to look at the orientation of a label on the outside of the brake booster pump assembly. The accumulator is a component located inside the brake booster pump assembly.

Toyota’s D0H technical instruction documentation states the part is defective and requires replacement if the label is horizontal. If the label is vertical it is not defective and does not require replacement.

Toyota gives no explanation as to how the label orientation identifies the defective accumulators. It is possible the orientation of the caution label indicates an internal design change of the accumulator or another related component.

It is unknown why 2010 Prius with vertically aligned caution labels were included in the safety recall population.

 

Toyota's September 2009 Brake Accumulator Update

Abbas Saadat’s defect information report for the D0H safety recall (NHTSA ID 13V-235) discusses the testing of brake accumulators in affected Prius vehicles.

The “October 2012 – May 2013” section of the “Chronology of Principle Events” section of Toyota’s D0H defect information report states, “The results of these tests confirmed that, if the amount of clearance is large, large impact forces may be exerted onto the metal bellows, which could result in gradual damage to the bellows. Toyota further analyzed the recovered in-use brake booster assemblies, and confirmed that a small number of brake boosters equipped with accumulators with large clearances were installed in vehicles produced before September 2009, when an updated brake accumulator, which was developed and introduced for other new models, was implemented in the subject vehicle production.”

This September 2009 brake accumulator manufacturing change was not disclosed in former NHTSA defect investigator Chris Santucci’s defect information report for Toyota’s A0B safety recall filed on February 9, 2010. Toyota’s A0B safety recall addressed “issues with the VSC/brake performance” and the fact that “customers are perceiving inconsistent brake feel after ABS actuation…”

As explained in Toyota’s Deferred Prosecution Agreement with the US Department of Justice, in which Toyota pled guilty to wire fraud for their illegal conduct during the Unintended Acceleration Scandal, “Although Toyota is not required to notify NHTSA of any engineering and design changes it made to Toyota and Lexus models sold in the United States, it is required to file a DIR for any safety-related defect addressed by such an engineering and/or design change.”

 

The Omission of the Brake Master Cylinder Assembly from the DIR

Toyota’s 13V-235 defect information report cover letter dated June 5, 2013 and signed by Abbas Saadat reads, “…we hereby submit the attached Defect Information Report…to address an issue with the brake booster pump assembly.”  The DIR continues in the “Description of Corrective Repair Action” section stating, “The dealer will inspect the brake booster pump assembly, and, if it is equipped with an affected accumulator, the dealer will replace the brake booster pump assembly with an improved one.”

The 13V-235 Defect Information Report does not mention a potential replacement of another brake related component – the Brake Master Cylinder Assembly (also referred to by Toyota as the Brake Booster Assembly).

The brake booster pump assembly and the brake booster assembly (aka brake master cylinder assembly) are separate components with different part numbers. Each part has distinct responsibilities pertaining to brake performance.

Toyota’s defect information report and dealer letter for the D0H safety recall do not mention the potential replacement the brake master cylinder assembly. However, it is referenced in the technical instructions for the D0H safety recall.

Toyota’s “Customer Frequently Asked Questions” published mid-July 2013 state, “…nitrogen gas could leak into the brake fluid and gradually cause al loss of power assist…this could affect stopping distance and increase the risk of a crash.”

It may be possible that a malfunction of the brake master cylinder causing one of the DTC codes to be present may not have occurred yet at the time the brake booster pump assembly was replaced under safety recall D0H. Even with the new brake booster pump assembly (containing the accumulator) installed a malfunction of the brake master cylinder causing a DTC code to be present may possibly occur in the future due to contaminants left behind from the old, defective brake booster assembly.

Toyota’s technical instructions state that the brake master cylinder assembly may only be replaced if Diagnostic Trouble Code (also known as DTC codes) C1246 or C1256 is already present within the vehicles. The presence of one of the DTC codes typically indicates that a malfunction or failure has already occurred in the system they pertain to (i.e. the brake system).

The limp-home (or fail-safe) mechanisms for DTC codes pertaining to the brake system include the vehicle having key mechanisms such as ABS, Brake Assist, Vehicle Stability Control, and Traction Control “prohibited” due to the defect.

This scenario may lead to post-D0H recall completion brake malfunctions. Safety recalls are legally required to prevent a dangerous defect from occurring. Requiring a DTC code to be present in order to receive a safe component means the vehicle must experience the brake malfunction before the new part is provided by Toyota.

 

The C1256 DTC Code

Toyota’s technical instructions for the D0H safety recall instruct technicians to “Check and record DTCs.” Then, if DTC code C1256 is present, “replace the brake booster pump assembly (accumulator) AND the brake booster assembly.” (Emphasis in original)

Diagnostic Trouble Code C1256 indicates “Accumulator Low Pressure.”

Limp-Home mechanisms for the brake control system, or fail-safe mechanisms, pertaining to the C1256 DTC code include “prohibition” of ABS, Brake Assist, Traction Control, Vehicle Stability Control, and Electronic Brake Distribution.

Limp-Home mechanisms for the hydraulic system, or fail-safe mechanisms, pertaining to the C1256 DTC code include “braking force generated solely by the driver.”

Many complaints pertaining to the Prius brakes indicate that the brake pedal was pushed all the way to the floor but remained unresponsive. This scenario may be linked to the fact that “braking force” would be generated “solely by the driver” when there is a malfunction regarding pressurization in the system.

June 16, 2014 NHTSA ID NUMBER: 10598545

Components: STRUCTURE, SERVICE BRAKES

NHTSA ID Number: 10598545

Incident Date March 27, 2014

Consumer Location ANACORTES, WA

Vehicle Identification Number JTDKN3DU1B1****

Summary of Complaint

CRASHYes

FIRENo

INJURIES0

DEATHS0

WHILE PULLING INTO A PARKING SLOT IN A PARKING LOT, WHICH WAS ON A SLOPE, I APPLIED THE FOOT BRAKE WITHOUT ANY RESPONSE WHATSOEVER. THE VEHICLE GAINED ENOUGH SPEED TO JUMP THE SMALL STOP-CURB AND HIT A CONCRETE WALL NEXT TO IT. THE DAMAGE TO THE FRONT OF THE CAR WAS JUST OVER $4000. I THOUGHT I HAD MISSED THE PEDAL. ON JUNE 12TH AND 15TH, I HAD TWO MORE INCIDENTS OF THE BRAKE PEDAL GOING ALL THE WAY TO THE FLOOR WHILE EITHER AT SLOW SPEED OR STOPPED. MY DEALER SAYS IT WAS A PROBLEM ON THE 2010, BUT HE HAS NOT SEEN IT ON A 2011. MY WIFE NOW REFUSES TO DRIVE THE CAR. *TR

1 Affected Product 

Request Research (Services fees apply)

 

The Chronology of Principle Events

The Chronology of Principle Events section of Abbas Saadat’s D0H defect information report (NHTSA ID 13V-235) begins in the time period of May 2010 – October 2011. The first sentence of the section states, “Toyota received a field report from the U.S. market indicating ABS, TRAC, VSC, and brake warning lamp illumination and malfunctioning brakes.”

The beginning of the Chronology of Principle Events section does not state when the first field report was received from the Japan market or the U.S. market. It states Toyota received “a” field report during that time period.

There are multiple complaints available on NHTSA’s safercar.gov website “indicating ABS, TRAC, VSC, and brake warning lamp illumination and malfunctioning brakes before May 2010.

It is possible that Toyota’s publicly unavailable preliminary evaluation PE10-006 - launched by NHTSA prior to the 2010 A0B safety recall - could assist in verifying the accuracy of the Chronology of Principle events from the D0H defect information report.

 

THE ZJB WARRANTY ENHANCEMENT

On August 9, 2018 Toyota announced Warranty Enhancement ZJB (also known as a Customer Support Program). The Customer Support Program covers 250,700 model year 2010 Prius vehicles. The “Background” section of the ZJB documentation states, “Toyota has received reports about certain internal malfunctions of the brake booster assemblies in some of the subject vehicles.”

Toyota's D0H safety recall called for the replacement of over 85,000 Prius brake booster assemblies.

ZJB's “Primary Coverage” expires on November 19, 2019. “Secondary Coverage” is applicable for 10 years from the date of first use or 150,000 miles – whichever occurs first.

Toyota’s Frequently Asked Questions documentation states that the ZJB warranty enhancement, “only applies to vehicles that have exhibited the condition described above.”

Safety recalls are legally required to prevent a dangerous defect from occurring. A warranty enhancement is a reactionary repair that takes place after a defect has occurred.

 

Same Components as A0B and D0H - Just More 2010 Prius

Toyota’s ZJB documentation directs you to TSB 0079-18 which explains that the program covers repair and replacement of the Brake Master Cylinder Assembly, repair and replacement of the Brake Booster Pump Assembly, and the reprogramming of the Skid Control ECU.

The Skid Control ECU referred to in Toyota’s ZJB documentation is also referred to by Toyota as the ABS Actuator ECU in Toyota’s safety recall A0B documentation (released in February 2010) and the Brake Actuator Skid Control ECU in TSB 0363-10 (released in December 2010).

The Brake Booster Pump Assembly covered by Toyota’s ZJB documentation is referred to as the Brake Booster Pump Assembly with Accumulator in Toyota’s technical instructions for the 2013 D0H safety recall.

The Brake Booster covered by Toyota’s ZJB documentation is referred to as the Brake Booster Assembly in Toyota’s technical instructions for the 2013 D0H safety recall.

Safety Recall A0B covered approximately 133,000 2010 Prius vehicles. Safety Recall D0H covered approximately 82,000 2010 Prius vehicles. Warranty Enhancement ZJB covers over 250,000 2010 Prius vehicles.

Safety recalls are legally required to prevent a dangerous defect from occurring. A warranty enhancement is a reactionary repair that takes place after a defect has occurred.

 

The D0H "Remedy" Part Numbers

The technical instructions for Toyota’s D0H safety recall call for the replacement of the defective Brake Booster Pump Assembly with Accumulator (if the caution label is horizontally oriented). The technical instructions state that “approximately 97% of vehicles will require the accumulator replacement.”

Toyota’s “remedy” part number for the defective Brake Booster Pump Assembly with Accumulator for safety recall D0H is 47070-47060.  The 47070-47060 Brake Booster Pump Assembly part number was superseded by the new part number 04006-22147 under Toyota’s ZJB warranty enhancement.

Toyota's DoH safety recall employed "remedy" part numbers 47050-47140 or 17050-47150 when the Brake Master Cylinder Assembly had to be replaced. When the Brake Master Cylinder has to be replaced under Toyota’s ZJB warranty enhancement, the new part numbers 04002-33347 or 04002-33447 are used.

It is unknown why the “remedy” part numbers from Toyota’s D0H safety recall have been subject to a super-cession - which may indicate a design change of the part.

 

DTC Code C1256

Toyota’s Introduction on Technical Service Bulletin 0079-18 states, “Some 2010 model year Prius and Prius Plug In vehicles may exhibit a condition where the brake, ABS, and/or TRAC warning light(s) are on and/or a check VSC message displays. Diagnostic Trouble Codes (DTCs) C1391, C1252, C1256, and C1253 may be stored.”

according to the TSB if the C1256 DTC code is present, replacement of the Brake Booster Mastery Cylinder, replacement of the Brake Booster Pump Assembly, and re-programming of the Skid Control ECU is required.

According to the technical instructions for Toyota’s D0H safety recall, DTC code C1256 may be present when the vehicle is presented for the safety recall. If the DTC code was present in the vehicle under safety recall D0H, a replacement of the Brake Booster Master Cylinder Assembly and replacement of the Brake Booster Pump Assembly (with accumulator) is required.

Toyota’s ZJB warranty enhancement covers over 250,000 Prius vehicles including and unknown volume of “2010” Prius Plug In vehicles.

Only 82,000 Prius were covered by safety recall D0H. There were no Prius Plug In vehicles covered by safety recall D0H or safety recall A0B.

 

2010 Model Year Prius Plug In

Only 82,000 Prius were covered by safety recall D0H - none of them were Prius Plug In hybrids. Toyota’s ZJB warranty enhancement covers over 250,000 Prius vehicles including an unknown volume of 2010 Prius Plug In vehicles manufactured between Late November 2009 and Late October 2010.

Interestingly, the Toyota Prius Plug In model was not for sale in the United States until the 2012 model year.

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