Service

Technical Information

31/20

ENU

2706

2

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

Vehicle Type:

Version

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 separator added

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

Model Year:

As of 2019

Equipment:

All lightweight batteries including Taycan (standard equipment) and Cayenne and 911 Carrera (I-no. J2A)

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.
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.
Information
Please also refer to the checklist in the section  Technical Information 'Battery diagnosis'.
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.

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'

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Feb 8, 2024
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Technical Information

31/20

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 .

Feb 8, 2024
Page 2 of 9

4

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

5

Read out the fault memory of the Gateway control unit and check for the following fault memory
entries.

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Technical Information

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Information
The 12-volt vehicle electrical system battery must be replaced after the test has been carried out
under the following prerequisites:
•

Test procedure was fully carried out twice

•

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

•

Fault still persists
Assessment

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

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

Observe the guided troubleshooting 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 separator (“Lithium-ion starter battery: battery separator,
fault status” or “Battery (12 V): battery separator, 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 must be appended to any request.
Battery status

Action

•
•
•

This is not a 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).

Fully charge 12-volt vehicle electrical system battery.
Then create another VAL and check the gateway
control unit again for existing fault memory entries
analogous to step 5.

The charging current is