Symptom-based workshop manual

Service
248/24 ENU

9301

9

Control Unit for High-Voltage Battery (BMC) Loss of Capacity / Range Implausible: Reset Cell Modules
(SY 248/24)
Change overview
Revision

Date

Change

0

02/05/2026

•

First publication

1

03/04/2026

•
•

Test step “Plausibility check of battery capacity” added.
Update to Symptom

Model Line:

Macan (XAB)

Model Year:

As of 2024

Concerns:

Cell modules

Symptom:

The customer complains that the displayed battery level does not match the displayed range and/or
detects a significantly reduced DC charging power and cannot trace it back to the respective charging
park.

Remedial
Action:

If there is a customer complaint, perform a plausibility check of battery capacity and, if necessary, reset the
cell modules using the Porsche Tester.

Required tools
Tools
Information:

•
•

P90999 - P90999 - Porsche 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'

Resetting the cell modules using the Porsche Tester
Information
After resetting the cell modules, the high-voltage battery adapts to the "start of life capacity" after the next
learning phase.
Work procedure: 1

Create vehicle analysis log (VAL).
1.1

Connect and switch on the battery charger.
⇒ Workshop Manual '270689 Charging battery/vehicle electrical system'

1.2

Place the original remote control in the emergency start tray.

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Service
ENU 248/24

9301

2

Symptom-based workshop manual

1.3

Connect P90999 - P90999 - Porsche Tester 4, establish readiness for operation and start the
diagnostic application.

1.4

Mark the created Vehicle Analysis Log (VAL) with the attribute "Pre-VAL" and return it using the
Porsche Tester after the action is completed.

Carry out a plausibility check of the battery capacity according to the instructions of the Porsche Tester.
2.1

Open high-voltage battery control unit (J1120).

2.2

Open “Maintenance repairs” menu.

2.3

Select the menu item “Plausibility check of battery capacity” and carry it out.
•

If no abnormalities were found during the plausibility check of the battery capacity, the
action ends.

•

If the plausibility check of the battery capacity results in a deviation, continue with Step 3.

3

Deactivate the high-voltage system.
⇒ Workshop Manual '931083 Deactivate and activate high-voltage system'

4

Reset the cell modules using the Porsche Tester.
4.1

Select the "High-voltage battery (J1120)" control unit in the "Overview" control unit selection
and confirm your selection by pressing •F12“ ("Next").

4.2

Select the "Maintenance repairs" menu. Then select the "Configuring cell module and/or
cell module controller" function and confirm by pressing •F12“ ("Next").

4.3

Follow instructions and information displayed on the Porsche Tester.

4.4

Select all 12 cell modules and reset the cell modules by pressing •F8“ ("Start").
Information
All 12 cell modules must always be selected.

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Symptom-based workshop manual

Service
248/24 ENU

9301

9

Selection of cell modules in the Porsche Tester
5

Activate the high-voltage system.

⇒ Workshop Manual '931083 Deactivate and activate high-voltage system'

Information
After the high-voltage system has been activated and before the fault memory is deleted, maintain a bus idle
of approx. 6 minutes.
Otherwise there is the possibility that the fault memory cannot be deleted.
6

Read out and delete all control unit fault memories.

7

Establish bus idle for at least 1 hour on the vehicle.
For this purpose:
•
•
•
•

8

Disconnect the battery charger
End the diagnostic application, end readiness for operation and disconnect P90999 - P90999 Porsche Tester 4 from the vehicle
Lock the vehicle
Place driver's key outside the frequency range of the vehicle

Fully charge high-voltage battery after bus idle.

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Symptom-based workshop manual

ENU 248/24

9301
9

Re-establish bus idle for at least 1 hour on the vehicle.
For this purpose:
•
•
•

Remove high-voltage charger from the vehicle
Lock the vehicle
Place driver's key outside the frequency range of the vehicle

10 Create vehicle analysis log (VAL).
10.1

Connect and switch on the battery charger.
⇒ Workshop Manual '270689 Charging battery/vehicle electrical system'

10.2

Place the original remote control in the emergency start tray.

10.3

Connect P90999 - P90999 - Porsche Tester 4, establish readiness for operation and start the
diagnostic application.

10.4

Mark the created Vehicle Analysis Log (VAL) with the attribute "Post-VAL" and return it using
the Porsche Tester after the action is completed.

11 End the diagnostic application, end readiness for operation and disconnect P90999 - P90999 Porsche Tester 4 from the vehicle.
12 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.

93252541

Program the high-voltage battery control unit
(performing plausibility check of battery capacity)

93252540

Programming the high-voltage battery control unit
(perform cell module reset)
PCSS encryption:

Location (FES5)

93010

Cell module

Damage type (SA4)

4076

Energy balance too low

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.

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