Service

Technical Information

31/20 ENU

2706

2

Diagnosis and Handling of 12-Volt Lithium-Ion Battery (Vehicle Electrical System Battery) (31/20)

Information
Please also refer to the Standard Form PNA 000 162 QM — Lithium-Ion Battery Checklist - Lightweight
battery 60 Ah, which can be found on PCSS.
For more information on the component protection functions of the 12-volt on—board battery and how they
work, see the ⇒ Technical Information 'Technical Background' section.
Change
Overview:

Revision

Date

Change

0

06/29/2020

•

First publication

1

10/13/2021

•

Update of Technical background and Procedure

2

01/06/2023

•
•

TI setup adapted
Information on battery diagnosis supplemented

3

03/30/2023

•

Checklist added in the “Battery diagnosis” section (prerequisite
for invoicing with Porsche AG)

4

08/11/2023

•

Information for Battery diagnosis updated

5

02/08/2024

•

Information for fault status of the battery cut-out element added

6

05/24/2024

•

Omission of the checklist within this Technical Information (TI)

7

07/24/2025

•

Update to Labor Position

8

09/25/2025

•
•

Limitation to equipment (M-no. J2A) removed
“Technical background” section revised

9

04/07/2026

•

Update to Questions & Answers, “Not relevant for Taycan” Information removed

Model Year:

As of 2018

Vehicle Type:

Cayenne (9YA/9YB)
911 Carrera (992)
Taycan (Y1A/Y1B/Y1C)

Concerns:

12-volt lithium-ion battery (12-volt vehicle on—board battery)

Cause:

On vehicles in which a lithium-ion vehicle electrical system battery is installed, the battery is sometimes
replaced even though it is not defective.

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Technical Information

31/20

This Technical Information is intended to help you to diagnose the battery in order to identify whether a
battery is actually defective or whether only a temporary component protection function, which can be reset
using appropriate measures, i.e. is reversible, was activated.
Content:

•
•
•
•

Battery diagnosis ⇒ Technical Information 'Battery diagnosis'
Technical background ⇒ Technical Information 'Technical background'
Charging 12-volt vehicle electrical system battery ⇒ Technical Information 'Charging the battery'
Questions and Answers ⇒ Technical Information 'Questions & Answers'

Battery diagnosis
Information
If in doubt about the status of the lithium-ion battery (e.g. due to smoke, steam, heat development, odor or
other abnormalities), first classify the lithium-ion battery according to the Workshop Manual ⇒ Workshop
Manual '2X00IN Classification of lithium-ion battery'.
Otherwise, continue with the battery diagnosis as described below.

Information
There is no approved battery tester for the lithium-ion battery. The existing battery testers do not work for
lithium-ion batteries because the algorithms for the acid/gel/AGM batteries are different.
By evaluating the actual values/measured values in the PIWIS Tester, it is possible that the status of the
battery can be checked by evaluating the values that are actually present. The battery must already be
installed in the vehicle at this time.
Work Procedure: 1

Connect a battery charger suitable for lithium starter batteries with a rated current of at least 90 A
(e.g. VAS 5908 battery charger 90 A) to the external power supply for jump-lead starting in the engine
compartment and operate in automatic mode.
For instructions, see: ⇒ Workshop Manual '2706IN External power connection, jump-lead starting'
and
⇒ Workshop Manual '270689 Charging vehicle electrical system and battery'

2

Connect P90999 - PIWIS Tester 4 to the vehicle communication module (VCI) via the USB cable. Then
connect the communication module to the vehicle and switch on the PIWIS Tester.

3

Switch on ignition.
Information
Please note that, during the entire test on the 12-volt vehicle electrical system battery, the engine must
not be started .

4

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Create vehicle analysis protocol (VAL) and mark it with the attribute ‘Pre-VAL’.

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Technical Information
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31/20 ENU

2706

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Read out the fault memory of the Gateway control unit and check for the following fault memory entries.
Information
If the test procedure has already been carried out twice from step 5 and has led to an identical result,
the 12-Volt vehicle electrical system battery must be replaced under the following circumstances:
•

Test procedure was performed twice in full (e.g. step 5 to step 10)

•

Test procedure was completed twice with the same result (e.g. allow 12-volt vehicle electrical
system battery to rest for 24 hours or charge the 12-volt vehicle electrical system battery)

•

Fault still persists
Assessment

Action

One of the following fault memory entries is stored
in the gateway control unit:
•
•

P1B0200 – 12-volt battery monitoring, no
function (8201CA)
P1D6C00 – 12-volt battery monitoring, no
function (82000C)

A fault memory entry is stored in the control unit
gateway with reference to a faulty line connection.
6

Check the fault status of the 12-volt vehicle
electrical system battery.
Continue with Step 6.

Observe the guided fault finding for the respective
specified fault memory entry.

Check the fault status of the 12-volt vehicle electrical system battery.
6.1

Select the gateway control unit in the control unit selection.

6.2

Select the ‘Actual values / input signals’ menu.

6.3

Check battery status.
To do this, proceed as follows:
•

Cayenne (9YA/9YB): Select the actual value group ‘Battery (12 V)’ and press •F12“
(“next”) to confirm your selection. In the subsequent overview, select the value ‘Battery
(12 V)’: Select “Fault status” and press •F12“ (“next”) to confirm.

•

Taycan (Y1A/Y1B/Y1C): Select the actual value group ‘Battery (12 V)’ and press
•F12“ (“next”) to confirm your selection. In the subsequent overview, select the value
‘Lithium-ion starter battery’: Select “Battery, fault status” and press •F12“ (“next”) to
confirm.

•

911 (992): Select the actual value group ‘Battery/battery sensor’ and press •F12“
(“next”) to confirm your selection. In the subsequent overview, select the value ‘Battery
(12 V): Select Fault status and press •F12“ (“next”) to confirm.

Then read off the respective status in the ‘Value’ field and evaluate it with the help of the
following table.

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Information
If the fault status of the battery cut-out element (“Lithium-ion starter battery: battery cut-out
element, fault status” or “Battery (12 V): battery cut-out element, fault status”) displays a fault,
the 12-volt lithium-ion battery (vehicle electrical system battery) must be replaced regardless
of the battery status (“Lithium-ion starter battery: battery, fault status” or “Battery (12 V): fault
status”).
Corresponding proof (i.e. Tester screenshot) must be attached to the PIWIS job.
Battery status

Action

•
•
•

No fault
Internal sensor fault
Battery deep discharge

12-volt vehicle electrical system battery can
be reactivated.
Continue with Step 7.

•
•
•

Restricted performance
Battery sensor defective
Fuse defective

Replace 12-volt vehicle electrical system
battery.
For instructions, see: ⇒ Workshop Manual
'270655 Replacing battery'

7

Erase fault memory entries for all control units.

8

Switch off ignition.

9

Disconnect P90999 - PIWIS Tester 4 from the vehicle.

10 After waiting for approx. 1 minute, read off the charging current on the charger.
Assessment

Action

The charging current increased significantly
(generally 60 A - 90 A).