No. 31-20

Service
Technical Information
31/20
ENU
2706
2
Diagnosis and Handling of 12-Volt Lithium-Ion Battery (On-Board 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
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 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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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. battery charger 90 A) to the external power supply for jump-lead starting in the engine
compartment and operate in automatic mode.
For work procedure, see:  Workshop Manual '2706IN External power connection, jump-lead
starting'
and
 Workshop Manual '270689 Charging vehicle electrical system and battery'
2
Connect 9900 - PIWIS Tester 3 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 .
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4
Create vehicle analysis protocol (FAP) and mark it with the attribute ‘Pre-VAL’.
5
Read out the error memory of the Gateway control unit and check for the following fault memory
entries.
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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.
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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.
7
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 work procedure, see:  Workshop
Manual '270655 Replacing battery'
Erase fault memory entries for all control units.
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8
Switch off ignition.
9
Disconnect 9900 - 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 FAP and check the gateway
control unit again for existing fault memory entries
analogous to step 5.
The charging current is <5 A.
12-volt vehicle electrical system battery is overcharged.
Continue with Step 11.
The charging current is <5 A and the “Battery
deep discharge” battery status was read out
beforehand.
Replace 12-volt vehicle electrical system battery.
For work procedure, see:  Workshop Manual
'270655 Replacing battery'
11 Switch off and disconnect the battery charger.
Then allow the 12-volt vehicle electrical system battery to rest for 24 hours.
12 After 24 hours of rest, measure the voltage at the 12-volt vehicle electrical system battery with a
suitable measuring device.
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Assessment
Action
The voltage of the 12-volt vehicle electrical system
battery is > 13 V.
Connect the battery charger and fully charge the
12-volt vehicle electrical system battery.
Then create another FAP and check the gateway
control unit again for existing fault memory
entries analogous to step 5.
The voltage of the 12-Volt electrical system battery
is 0 V.
For a few seconds, connect a voltage of 14.4 V
directly to the 12-volt vehicle electrical system
battery. If necessary, the separating element can
be closed (in this case, a single clicking noise is
audible).
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If the separating element closes, charge the
12-volt vehicle electrical system battery via
the external starting points using a suitable
charger.
•
If the isolation element does not close
or opens again directly after removing
the power source, the 12-volt electrical
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system battery must be replaced. For
work procedure, see:  Workshop Manual
'270655 Replacing battery'
Information
In order to invoice Porsche AG for work for diagnosis and, if necessary, for replacing the 12-volt
lithium-ion on-board battery, the checklist listed here must be completed and attached to the relevant
PCSS line.
Otherwise, we reserve the right to reject or charge back the claim.
Checklist:
1
General data
Vehicle identification number: __________________________________
Cause of discharge, if known (e.g. closed-circuit current, vehicle idle time, etc.):
_________________________________________________________________________________
_________________________________________________________________________________
______________________________________________________
2
External charging influences on the battery
Yes
No
Yes
No
Was the battery charged by a breakdown service?
Was a jump-lead attempt made by the customer or third parties?
3
Diagnostics
Before the repair, a vehicle analysis log (VAL) was created and marked
accordingly.
The vehicle on-board battery was connected to the vehicle (+, - and Lin).
The gateway control unit was checked for relevant diagnostic entries.
According to the diagnosis, the battery was in the following condition (please check):
This is not a fault
Internal sensor fault
Battery deep discharge
Restricted performance
Battery sensor defective
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Fuse defective
The battery could not be reached via diagnosis
No relevant faults were stored
The fault case is not covered by the procedure described in the TI.
Explain the situation accordingly in the respective PCSS job.
Yes
No
After repairs, was a vehicle analysis log (VAL) created and marked accordingly?
Date: ____________________
Signature: ___________________________________________
Technical background
Information:
The battery control unit, the battery sensor and an isolating element (contactor) are integrated in the
lithium-ion battery. This control unit monitors the charging and discharging of the battery and opens the
disconnecting element in the event of overcharging, deep discharge or overheating, for example, by interrupting the power supply to the battery. As a result, there is no voltage present at the battery terminals.
Therefore, no voltage can be measured at the battery terminals (value is between 0 V - 2 V).
If the separating element is open, the vehicle is de-energized. This may be perceived as a
battery fault, for example.
Opening conditions for the separating element:
Information
The voltage values given below are internal battery voltage values that cannot be read or measured.
The status in the current FAP is always decisive for a battery diagnosis.
The overview is only intended to provide information about the behavior of the 12-volt on-board power
supply battery and its separating element.
•
•
•
•
The separating element opens when the charge state (SoC) drops below 15% or the battery voltage
drops below 10 V.
The separating element opens when the battery voltage exceeds 16 V.
The separating element opens permanently if the voltage falls below 6.5 V or exceeds 18 V. This
state is irreversible. The battery must be replaced.
The separating element opens in the event of overheating or short circuit. A classification document
for the 12 V lithium-ion battery is stored in the PCSS, see  Workshop Manual '2X00IN Classification
of lithium-ion battery'.
Charging 12-volt vehicle electrical system battery
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Use a suitable battery charger
Set the correct charge voltage and charging current
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Work procedure for a discharged battery
Work procedure for an overcharged battery
Work procedure for a totally discharged battery
NOTICE
Important!
•
Only use Deutronic charger VAS 5908.

Battery chargers that are not suitable for lithium-ion batteries cannot be used.
To prevent damage to the battery and vehicle electrical system, a charger that is suitable for lithium-ion
batteries must be used - Battery charger 90A. The charger must also be set correctly. To do this,
change the charging values as shown below.
Information
If the battery charging current is lower than the power consumption of the vehicle, the contactor will open
if the system voltage drops.
When the contactor opens, non-certified chargers can cause voltage peaks above 28 V at present. This
can damage the battery.
Information
In most cases, the charging values must be changed.
Detailed information can be found under Special tools in the PPN or in the Workshop Manual/operating
instructions for the charger.
Set charging values as follows:
Voltage:
14.4 V
Maximum charging current:
90 A
Trickle charge voltage:
13.5 V DC
Cut-in voltage:
5.0 V DC
Trickle current:
5.0 A
Capacitive charging current:
5.0 A
Work procedure for a discharged battery
Information
If the battery is discharged, charge the battery as described and set the charging values specified
above.
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Questions & Answers
Is it possible to jump-start a vehicle with a lithium-ion battery?
See relevant section in the Driver’s Manual of the vehicle.
What happens if a standard AGM battery is installed in the vehicle instead of the specified
lithium-ion battery?
The installation of a standard AGM battery in Cayenne (9YA/9YB) / Taycan (Y1A) / 911 Carrera (992)
vehicles equipped with a lithium-ion battery is not permitted.
If a standard AGM battery is installed in the vehicle, a warning message will be displayed because there is
no LIN communication. The power supply network switches to emergency operation.
Can customers charge the battery at home?
The 12-volt lithium-ion battery can be charged using the Porsche Charge-o-mat Pro.
For further information, refer to the operating instructions for the charger or contact Porsche
Tequipment.
Information
Not relevant for the Taycan
Taycan vehicles cannot be charged using the Charge-o-mat Pro charger.
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.
© 2023 Porsche Cars North America, Inc.
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