Service

Technical Information

2025

ENU

WSH6

9

WSH6 - Re-Coding Control Unit for Left and Right Headlights (Workshop Campaign)
Important:

CRITICAL WARNING -This campaign includes steps where control unit(s) in the vehicle will be programmed
with the PIWIS Tester. The vehicle voltage must be maintained between 13.5 volts and 14.5 volts during this
programming. Failure to maintain this voltage could result in damaged control unit(s). Damage caused by
inadequate voltage during programming is not a warrantable defect. The technician must verify the actual
vehicle voltage in the PIWIS Tester before starting the campaign and also document the actual voltage on the
repair order.

Model Year:

As of 2020 up to 2024

Model Line:

Taycan (Y1A / Y1B / Y1C)

Equipment:

LED headlights (M-No. 8BM)
or
LED headlights including Porsche Dynamic Light System Plus (M. No. 8IS)

Concerns:

Control unit for left and right headlights

Cause:

On the affected vehicles, there is the possibility that the left and/or right headlight ventilation is not
activated in certain driving situations.
This may lead to a failure of the road illumination in the vicinity over the service life. Subsequently, a warning
message "Check dipped beam defective headlights" is displayed on the instrument cluster.

Action:

Re-code the left and right control unit for headlights using the PIWIS tester.
Information
The minimum requirement for coding is the PIWIS Tester software release 43.500.020 (or higher).

Affected
Vehicles:

Only vehicles assigned to the campaign (see also PCSS Vehicle Information).

Required tools
Tools:

•
•

P90999 - PIWIS Tester 4
Battery charger with a current rating of at least 90 A and a current and voltage-controlled charge map
for lithium starter batteries, e.g. VAS 5908 battery charger 90 A. For further information about the
battery chargers to be used, see the corresponding Workshop Manual. ⇒ Workshop Manual '270689
Charging vehicle electrical system battery'

AfterSales

Jul 17, 2025
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9

Service
WSH6

ENU

Technical Information

2025

Re-coding control unit for left and right headlights
Work Procedure: 1

Re-code the left and right control unit for headlights.
The basic procedure to be followed for coding the control unit is described in the Workshop Manual ⇒
Workshop Manual '9X00IN Basic instructions and procedure for control unit programming using the
PIWIS Tester'
For specific information on coding of control units during this campaign, see the table below.
Required PIWIS Tester software release:

43.500.020 (or higher)

Type of control unit coding:

Control unit coding using the “Automatic coding”
function for the control units:
Select Left headlight control unit (A31)
and Right headlight control unit (A27) –
“Coding/programming” menu – “Automatic coding”
function.

Coding sequence:

Read and follow the information and instructions on
the PIWIS Tester during the guided coding sequence.
Do not interrupt coding.
When coding is complete, the message “Coding has
been completed successfully” is displayed, and a tick
appears in the “Status” box.

Procedure if control unit coding is not
successful:

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Repeat control unit coding.

2

Read out and delete all control unit fault memories.

3

End the diagnostic application. End readiness for operation and disconnect P90999 - PIWIS Tester 4
from vehicle.

4

Switch off and disconnect the battery charger.
⇒ Workshop Manual '270689 Charging vehicle electrical system battery'

5

Enter the campaign in the Warranty and Maintenance logbook.

AfterSales

Service

Technical Information

2025

ENU

WSH6

9

Warranty processing
Information
The specified labor time was determined specifically for carrying out this campaign and includes all
necessary preliminary and rework. The labor time may differ from the labor times published in the Labor
Operation List in PCSS.
Scope 1:

Re-coding control unit for left and right headlights
Labor time:
Re-coding control unit for left and right headlights
Includes:
Connecting and disconnecting battery charger
Connecting and disconnecting PIWIS Tester
Reading out and deleting fault memories

Labor time: 32 TU

⇒ Damage number WSH6 066 000 1

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.

© 2025 Porsche Cars North America, Inc.

AfterSales

Jul 17, 2025
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