Bulletin #: 2309.2

Advanced Technical Information

Part ID: 4777

4

718 GTS 4.0 - Brake Booster (Power Brake) Warning in Instrument Cluster
Vehicles Affected
Models

Model Year

Model Type

VIN Range

Vehicle-Specific Equipment

718

2021 - 2024

982160
982360
982370

n/a

n/a

Revision History
Revision

Release Date

Changes

0

May 25, 2023

Original document

1

September 22, 2023

Update of MY, Condition, Technical Background & Service Information

2

November 16, 2023

Update of Technical Background

Condition
Customer complains of a “Power brake error” or “Brake booster fault” warning in the instrument cluster upon
starting the vehicle. These warnings may also be accompanied by a check engine light. The workshop finds fault
code P055600 (DTC 0011OB) stored in the DME. If a check engine light is present, a corresponding fault code
will appear in the Instrument Cluster control unit.
P055600 fault descriptions include:
Brake vacuum sensor - implausible signal
Brake Booster Pressure Sensor Circuit Range/Performance
Electric vacuum pump - power too low

Technical Background
The diagnostic function for checking the delivery rate of the electronic vacuum pump runs when Terminal 15 is
activated after the vehicle has slept for 25 minutes or more.
The value of the vacuum line pressure sensor (3 in Figure 1 below) upstream of the brake booster is stored
immediately after Terminal 15 is activated. The value is recorded again after 1.5 seconds. Fault P055600 sets if the
difference between the two values does not meet or exceed the threshold defined by the DME.

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Bulletin #: 2309.2

Advanced Technical Information

Part ID: 4777

4

Although this fault is possible at any altitude, it is more likely
to occur at higher altitudes due to the lower ambient pressure.
A software solution is expected by Summer 2024 to assist in
cases where the aforementioned fault is not caused by a vacuum
system leak. This document will be updated accordingly as more
information becomes available.

Figure 1

Service Information
1.
2.

Create a pre-VAL to document the occurrence of the fault.
Check the following areas of the vacuum system for obvious leaks:
a.
Check the vacuum line connections at the pressure accumulators underneath the intake manifold
(5 and 6 in Figure 2 below).
NOTE: The intake manifold must be removed to completely check the pressure accumulators.
=> WM 244619 Removing and installing intake air-distributor

Figure 2

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Bulletin #: 2309.2

Advanced Technical Information
b.

Part ID: 4777

4

Check the vacuum line connections on the electric vacuum pump (2 in Figure 3 below).

Figure 3
c.
3.

4.

Check the vacuum line connection on the brake booster, as well as the function of the vacuum line
pressure sensor in the PIWIS Tester (DME => Actual values/input signals=> A_General => A250_
Brake negative pressure absolute (measured)
If no obvious leaks are found in the system checks in Step 2, replace the following components:
- Figure 1: numbers 3, 4, and 5
- Figure 2: numbers 1-6
- Figure 3: numbers 1 and 2
If the fault further persists, please refer to Guided Fault Finding (DME P055600) for additional information.
Please document all additional work performed

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Bulletin #: 2309.2

Advanced Technical Information

Part ID: 4777

Warranty
As always, please document the repair completely in PQIS. For this repair, please code the “cause” as follows:
Cause location:
47770 Vacuum hose
Cause symptom:
5021 Not airtight
Use the following troubleshooting labor operations:
03350050
On board diagnostic
24461925
Intake distributor remove and reinstall
70081915
Trim panel for convertible top compartment remove and reinstall
Additional labor operations may be claimed only as needed.

Search Items
718, 982, GTS 4.0, Boxster, Cayman, P055600, DME, brake booster, power brake, vacuum pump, pressure sensor

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.

F14204
©2023 Porsche Cars North America, Inc.

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