Service

Technical Information

245/24 ENU

2706

2

Vehicle Electrical System Battery Discharged- It is Not Possible to Start or Unlock Vehicle (245/24)
Change Overview
Revision

Date

Change

0

04/25/2025

•

First publication

1

03/10/2026

•

Update to step 5 of work
procedure. Added “Example
of VAL view with value 27”

Model Line:

Cayenne (9YA / 9YB)

Model Year:

As of 2019 up to 2021

Equipment:

Head-Up Display (KS1)

Concerns:

Windshield projection control unit (Head-up display)

Information:

The customer complains that the vehicle does not open or cannot be started.
A discharged vehicle electrical system battery is detected in the workshop.

Cause:

The vehicle electrical system battery can be discharged by a continuously active head-up display control unit.
Information
No fault memory entries regarding the complaint are stored in the fault memory of the head-up display
control unit.

Action:

For an existing customer complaint, check the measured value described in this Technical Information (TI)
and reprogram the head-up display control unit with the PIWIS tester if necessary.
Information
The minimum programming requirement is the PIWIS Tester software release 43.300.015 (or higher).

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. battery charger 90 A. For further information about the battery
chargers to be used, see the corresponding Workshop Manual. ⇒ Workshop Manual '270689 Charging
the vehicle electrical system battery'

AfterSales

Mar 10, 2026
Page 1 of 4

2

Service

Technical Information

ENU 245/24

2706

Check measured value and reprogram head-up display control unit if necessary
Work procedure: 1

Connect and switch on the battery charger.

⇒ Workshop Manual '270689 Charging battery/vehicle electrical system'

2

Place the original remote control in the emergency start tray.

3

Connect the P90999 - PIWIS Tester 4, switch on ignition and start the diagnostic application.

4

Create vehicle analysis log (VAL).

5

In the vehicle analysis log (VAL), select the 'Gateway' control unit and check the following under
measured value 'Life_cycle_data_66 - ECU_1' or ‘History data 66 [1]: Review control unit (1)’ for the
last event ⇒ Example of VAL view with value 27.
Assessment
The value 27 is not stored as the last event.

Action
The complaint described in this Technical
Information is not caused by a continuously
active head-up display control unit.
Continue troubleshooting elsewhere.
End of action.

The value 27 is stored as the last event.

Software for head-up display control unit out of
order.
Continue with Step ⇒ 6.

Example of VAL view with value 27

Mar 10, 2026
Page 2 of 4

AfterSales

Service

Technical Information
6

245/24 ENU

2706

2

Re-program head-up display control unit.
The basic procedure for control unit programming is described in the Workshop Manual and must be
followed. ⇒ Workshop Manual '9X00IN Basic instructions and procedure for control unit programming
using the PIWIS Tester'
Specific information on control unit programming in the context of this Technical Information:
Required PIWIS Tester software release:

43.300.015 (or higher)

Type of control unit programming:

Control unit programming using the ‘Campaign’
function in the additional menu on the PIWIS Tester
by entering a programming code.

Programming code:

E3H9D

Programming sequence:

Read and follow the information and instructions on
the PIWIS Tester during the guided programming
sequence.
The head-up display control unit is reprogrammed
during the programming sequence.
The control unit is then re-coded automatically.
Do not interrupt the programming and coding
process.
Once the control units have been programed and
coded, you will be prompted to switch the ignition
off and then back on again after a certain waiting time.
Backup documentation of the new software releases
is then performed.

Programming time:

Programming takes up to 35 minutes, depending on
equipment.

Software release programmed during this
action:

• Head-up display control unit with
Hardware version: 07
Software version: 2401 (or higher)
Following control unit programming, the software
release can be read out from the relevant control unit
using the PIWIS Tester in the menu ⇒ ‘Incremented
identifications’.

Procedure in the event of error messages
appearing during the programming
sequence:

⇒ Workshop Manual '9X00IN Basic instructions and

Procedure in the event of a termination in
the control unit programming:

Repeat control unit programming by restarting
programming.

procedure for control unit programming using the
PIWIS Tester'.

AfterSales

Mar 10, 2026
Page 3 of 4

2

Service

Technical Information

ENU 245/24

2706
7

Read out and delete all control unit fault memories.

8

Exit the diagnostic application, switch off the ignition and disconnect P90999 - PIWIS Tester 4 from
the vehicle.

9

Switch off and disconnect the battery charger.

⇒ Workshop Manual '270689 Charging the vehicle electrical system battery'

Labor position and PCSS encryption
Labor position:
APOS

Labor operation

I No.

90862545

Re-programming head-up display control unit
PCSS encryption:

Location (FES5)

90860

Control unit for head-up display

Damage type (SA4)

4034

automated on/off switch

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.

© 2026 Porsche Cars North America, Inc.

Mar 10, 2026
Page 4 of 4

AfterSales