Service

Technical Information

105/25 ENU

4770

4

Active Malfunction Indicator Light in Conjunction with Fault Memory Entries Regarding Brake Booster
"U01B400" and "C114113" (105/25)
Model Line:

Panamera (YAA/YAB)
Cayenne (9YA/9YB)

Model Year:

As of 2024

Concerns:

Brake booster

Situation:

Customers complain about the malfunction indicator light lighting up on the instrument cluster.
In addition, the fault memory entries listed below are stored:
Porsche Stability Management (PSM) control unit:
•

U01B400 - Brake booster control unit, no communication (C1B400)

Brake booster control unit (EBKV):
•

C114113 - Control unit not shut down correctly (02FF00)

Information
The local overrun of the brake booster was not completed. Subsequently, the fault memory entry "C114113
- Control unit not shut down correctly (02FF00)" is set and the malfunction indicator light is activated.
It is not necessary to replace the brake booster with this fault pattern.
Action:

If there is a customer complaint and if the fault memory entries listed are entered in the control units, delete
the fault memory using the procedure described below.

Required tools
Tools:

•
•

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. VAS 5908 battery charger 90 A. For further information about the
battery chargers to be used, see the corresponding Workshop Manual. ⇒ Workshop Manual '270689
Charging vehicle electrical system battery'

Perform procedure and delete fault memory
Work Procedure: 1

Switch ignition on and then off again.

AfterSales

Jan 12, 2026
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4

Service

Technical Information

ENU 105/25

4770

Information
After the ignition has been switched off, there must not be any functions that keep the vehicle awake
active.
The brake booster then switches to local overrun and continues to provide braking force reinforcement
for approx. one minute. At the end of this minute, the brake booster is switched off and local overrun is
completed.
2

After about one minute, check whether the overrun is finished. To do this, press the footbrake.
•
•

If the brake booster is still present, ⇒ extend waiting time and then check again. The local overrun
was not yet completed in this case.
If the brake booster is no longer present ⇒ continue to step 3⇒ .

3

Switch on and connect battery charger.
⇒ Workshop Manual '270689 Charging vehicle electrical system battery'

4

Connect P90999 - Porsche Tester 4, switch on the ignition and start the diagnostic application.
Information
The fault memory entry “C114113 - Control unit not shut down correctly (02FF00)” is now passive and
can be deleted.

Jan 12, 2026
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5

Read out and erase the fault memories of the control units.

6

Exit the diagnostic application, switch off the ignition and disconnect P90999 - Porsche Tester 4 from
the vehicle.

7

Switch off and disconnect the battery charger.
⇒ Workshop Manual '270689 Charging vehicle electrical system battery'

AfterSales

Service

Technical Information

105/25 ENU

4770

4

Labor position and PCSS encryption
Labor position:
APOS

Labor operation

I No.

47700140

Read out and delete the fault memory
PCSS encryption:

Location (FES5)

47700

Brake booster

Damage type (SA4)

1614

Function not according to specification

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.

AfterSales

Jan 12, 2026
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