2

Bulletin #: 2422

Advanced Technical Information

Part ID: 2708

Taycan: Tips for completing HV Battery State of Health (SoH) Test Procedure in PIWIS
Tester
Vehicles Affected
Models

Model Year

Model Type

VIN Range

Vehicle-Specific Equipment

Taycan

As of 2020

Y1A

N/A

N/A

Taycan Cross Turismo

As of 2021

Y1B

N/A

N/A

Taycan Sport Turismo

As of 2022

Y1C

N/A

N/A

Revision History
Revision

Release Date

Changes

0

July 19, 2024

Original document

Condition
Successfully completing the HV Battery SoH test can be difficult without supporting information. The following
documentation aims to assist Porsche Center service and support personnel with relevant and necessary
information to successfully perform the SOH test procedure.

Technical Background
The HV Battery SoH long-term test procedure is designed to estimate the useable capacity of the HV battery as
accurately as possible. Currently, this involves completely discharging the battery before beginning the multi-day
procedure of holding and charging. Keep in mind that this procedure must be completed with the same PIWIS
tester that it was started with. Make sure that the PIWIS Tester is updated to the latest software before beginning
the procedure. Updating the software before the procedure is complete will erase the current progress and restart
the procedure from the first step.

AfterSales

July 19, 2024
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Bulletin #: 2422

Advanced Technical Information

Part ID: 2708

2

Service Information
When starting the procedure in the Maintenance repairs section of the HV Battery Control Unit, the tester will give a
full overview of the long-term measurement procedure. All steps must be performed in the order listed with the
same tester. It is highly recommended to reconnect the VCI to the vehicle to verify completion of each step in the
calculation preparation process.
Tips for discharging:
•
While the tester says to reach an SOC below 10%, this equates to a customer-facing SOC of 5% or less in

the instrument cluster.
•
Due to the potential of self-balancing during the first 6.5 hour holding period, a customer-facing SOC of
1-2% is highly recommended to ensure the minimum SOC criteria is met over the course of the holding
time.
Tips for holding time 1:
•
Once the discharging process is complete, the internal timer for the first 6.5 hour holding time will start

automatically. and display the time elapsed. Note that this timer restarts each time the tester is connected

to the vehicle, until the 6.5 hour minimum is surpassed.
•
Set a separate timer of at least 6.5 hours from the point you disconnect the tester and lock the vehicle to

begin the first holding period.
•
Do not disturb the vehicle during this time. Reconnecting the tester at any point before the 6.5 hour holding

period will restart the internal timer in the test procedure criteria.
•
There is no maximum time limit for either holding time. If the car needs to sit overnight or over the weekend,

the procedure can still be resumed afterward.
Tips for charging:
•
This process must be performed with an AC charger. The power level does not matter, but level 2 AC

charging is obviously recommended due to the kWh required to reach >90% SOC.
•
To save time charging, it is recommended to set at least a 95% SOC limit charge profile in the PCM for this

charging session. This will display the soonest time to unplug the charger in the lower display when the

profile is active.
•
Anything less could risk the 90% SOC requirement not being met in the PIWIS tester for completion of the
charging step.
Tips for holding time 2:
•
The timer behavior for the second holding time is identical to the first one. Make sure to leave the vehicle

undisturbed in a temperature-controlled environment for at least 6.5 hours from the moment you lock the

car after completing the charging session if you removed the charging plug immediately after charging.
•
This period will start automatically after the vehicle is done charging. It is possible to leave the charger

connected until the 2nd 6.5 hour holding time is complete (overnight for example). A calculation should be

prepared after this point.

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July 19, 2024
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Bulletin #: 2422

Advanced Technical Information

Part ID: 2708

Generating a certificate:
•
While the procedure has become more robust with the latest PIWIS tester software, the possibility remains

that the calculation could fail. The only option in this case is to end the process and start over. Be sure to

check fault memory for any new faults that might be affecting the communication of the HV Battery Control
Unit.
•
Once a calculation is prepared and a certificate available, this value can be referenced again by returning to

the SoH test routine in the tester.
•
An additional long-term test can be started from that point, but the current value from the previous

calculation serves as the “short test” from previous tester software versions. So far it is not possible to

prepare a calculation of SoH without performing the long-term measurement procedure first.
This document will be updated as the procedure changes in future PIWIS tester software releases.

Warranty
No warranty Labor Operations are currently available as this procedure is performed on an as-needed basis.

Search Items
Taycan, HV Battery, high voltage, state of health, SOH, Capacity, PIWIS

Important Notice: Technical Bulletins issued by Porsche Cars North America, Inc. are intended only for use by professional automotive technicians who have attended Porsche service training courses. They are
written to inform those technicians of conditions that may occur on some Porsche vehicles, or to provide information that could assist in the proper servicing of a vehicle. Porsche special tools may be necessary in
order to perform certain operations identified in these bulletins. Use of tools and procedures other than those Porsche recommends in these bulletins may be detrimental to the safe operation of your vehicle, and
may endanger the people working on it. Properly trained Porsche technicians have the equipment, tools, safety instructions, and know-how to do the job properly and safely. Part numbers listed in these bulletins
are for reference only. The work procedures updated electronically in the Porsche PIWIS diagnostic and testing device take precedence and, in the event of a discrepancy, the work procedures in the PIWIS Tester
are the ones that must be followed.

©2024 Porsche Cars North America, Inc.

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