No. 205-21-1

Service
Technical Information
205/21 ENU
9170
9
Message "Lane Change Assist Not Available – Service Necessary" in the Instrument
Cluster: Re-Programming Lane Change Assist Control Units (205/21)
Model Line:
911 (992)
Model Year:
2021
Equipment:
Lane Change Assist (I-no. 7Y1)
Concerns:
Lane Change Assist control unit
Information:
•
•
The white warning message 'SWA not available – Service necessary' is displayed intermittently
in the instrument cluster. The warning message disappears after a few seconds even though the
ignition is not switched off and on again.
The fault memory entry 'B200FF9 – Control unit faulty' is stored in the fault memory of the
Lane Change Assist control unit. This can be caused by a software error in the control unit, which
detects and calculates an excessive number of objects when driving in particularly high detection
environments (e.g. high traffic volume on multi-lane roads), which can lead to a runtime overrun of
the processors' computing time. The control unit then sets an error code and intermittently switches
off the affected assistance systems until the error routine (self-healing) is completed.
Action required: In the event of a customer complaint, re-program the Lane Change Assist control units using the installed
PIWIS Tester with test software version 40.750.050 (or higher).
•
•
Lane Change Assist, left (slave)
Lane Change Assist, right (master)
Information
If control unit programming is performed for one of the two control units, the other Lane Change Assist
control unit is also programmed automatically to the required level.
Information
The total time required for control unit programming is approx. 6 minutes.
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Feb 14, 2022
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Service
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ENU
Technical Information
205/21
Required tools
Information
The new 911 (992) is equipped with either a lithium starter battery (M-no. J2A) or an AGM starter
battery (M-no. J0V, J4K) as standard.
This depends on the following:
•
Country version
•
Model type
•
Vehicle equipment
Lithium starter batteries must only be charged using a suitable battery charger that has a current
and voltage-controlled charge map.
For further information about the battery chargers to be used, see  Workshop Manual '270689
Charging battery/vehicle electrical system'.
Tool:
•
•
Battery charger with a current rating of at least 90 A and, if required, also with a current and
voltage-controlled charge map for lithium starter batteries, e.g. VAS 5908 battery charger,
90A
9900 - PIWIS Tester 3 with installed PIWIS Tester software version 40.750.050 (or higher)
Preparatory work
NOTICE
Fault entry in the fault memory and control unit programming aborted due to low voltage.
•
Increased current draw during diagnosis or control unit programming can cause a drop in voltage, which
can result in one or more fault entries and the abnormal termination of the programming process.

Before getting started, connect a suitable battery charger with a current rating of at least 90 A to the
jump-start terminals.
NOTICE
Control unit programming will be aborted if the WLAN connection is unstable.
•
An unstable WLAN connection can interrupt communication between PIWIS Tester II and the vehicle
communication interface module (VCI). As a result, control unit programming may be aborted.

During control unit programming, always connect the PIWIS Tester to the vehicle communication module
(VCI) via the USB cable.
NOTICE
Control unit programming will be aborted if the driver's key is not recognized
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Service
Technical Information
205/21 ENU
9170
9
•
If the driver's key is not recognized in the vehicle, programming cannot be started or will be interrupted.

Place the driver's key with the back facing down in front of the lock opening for the center console cover to
guarantee a permanent wireless link between the vehicle and driver's key.
Work Procedure: 1
Carry out general preliminary work for control unit programming as described in  Workshop
Manual '9X00IN Basic instructions and procedure for control unit programming - section on
"Preliminary work"'.
Re-programming control units for Lane Change Assist
NOTICE
Use of a PIWIS Tester software version that is older than the specified version
•
Measure is ineffective

Always use the specified version or a higher version of the PIWIS Tester software for control unit
programming and coding.
Work Procedure: 1
The basic procedure for programming a control unit is described in the Workshop Manual 
Workshop Manual '9X00IN Basic instructions and procedure for control unit programming using the
PIWIS Tester - section on "Programming"'.
Specific information on control unit programming in the context of this Technical Information:
Required PIWIS Tester software version:
40.750.050 (or higher)
Type of control unit programming:
Control unit programming using the 'Automatic
programming' function for the right Lane Change
Assist control unit (master) or left Lane Change Assist
(slave):
‘Lane Change Assist right (master)’ control unit
or 'Lane Change Assist, left (slave)' –
'Coding/programming' menu – 'Automatic
programming' function.
If control unit programming is performed for one of the
two control units, the other Lane Change Assist control
unit is also programmed automatically to the required
level.
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Technical Information
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Read and follow the information and instructions
on the PIWIS Tester during the guided programming
sequence.
During the programming sequence, the 'Lane Change
Assist, right (master)' and 'Lane Change Assist,
left (slave)' control units are re-programmed and
then re-codedautomatically.
Programming sequence:
Do not interrupt programming and coding.
Once the control units have been programmed 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 versions is
then performed.
Programming time (approx):
6 minutes
Software version programmed during
programming:
0588 (or higher)
Procedure in the event of abnormal termination of control unit programming:
•
•
Following control unit programming, the software
version can be read out of the relevant control unit in
the  'Extended identifications' menu using the PIWIS
Tester.
•
Procedure in the event of error messages
appearing during the programming
sequence:
Switch ignition off and then on again.
Reading out and erasing fault memories. 
Workshop Manual '9X00IN Basic instructions and
procedure for control unit programming using the
PIWIS Tester - section on "Rework"'
Repeat control unit programming by restarting
programming.
 Workshop Manual '9X00IN Basic instructions and
procedure for control unit programming using the
PIWIS Tester - section on "Troubleshooting"'.
Concluding work
Work Procedure: 1
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Carry out general rework for control unit programming as described in  Workshop Manual '9X00IN
Basic instructions and procedure for control unit programming using the PIWIS Tester - section on
"Rework"'.
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Technical Information
205/21 ENU
9170
9
Invoicing
For documentation and warranty invoicing, enter the working position and PCSS encryption specified
below in the warranty claim:
I No.
APOS
Labor operation
91702500
Programming control units for Lane Change
Assist
PCSS encryption:
Location (FES5)
91700
Lane Change Assist control unit does
Damage type (SA4)
1613
not function at times
References:
 Workshop Manual '270689 Charging battery/vehicle electrical system'
 Workshop Manual '9X00IN Basic instructions and procedure for control unit programming using the
PIWIS Tester'
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.
© 2022 Porsche Cars North America, Inc.
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