No. 174-23 Service Bulletin/Repair Instructions

Service
Technical Information
174/23 ENU
8734
Little or No Cooling Power from the Air-Conditioning System: Checking Refrigerant Lines on

Air-Conditioning Compressor (174/23)
8
Change Overview
Model Line:
Version
Date
Change
0
11/29/2023
•
First Publication
1
01/27/2026
•
Update of Order Types and

MY
Panamera (971 / YAA / YAB)

Cayenne (9YA / 9YB)
Model Year:
As of 2019
Equipment:
Without alternative drive system (M-No. 0K0)
Concerns:
Air-conditioning compressor
Information:
Customers complain that the air-conditioning system cooling performance is too low. Drop formation of

refrigerant compressor oil is detected at the low point of the air-conditioning compressor housing. ⇒ Drop

formation on air-conditioning compressor
Drop formation on air-conditioning compressor
AfterSales
Jan 27, 2026

Page 1 of 7
8
Service

8734
ENU
Technical Information
174/23
Insufficient sealing of the refrigerant lines on the air-conditioning compressor can lead to a leak in the air-conditioning

system.

This leak can be caused by a twisted O-ring ⇒ Twisted

O-ring installed in conjunction with the design-related burr

Þ Twisted O-ring -1- or by a damaged O-ring

on the O-ring ⇒

on the refrigerant line.

As a result, refrigerant compressor oil can leak and collect

at the flange of the refrigerant line and at the lowest point of

the air-conditioning compressor.
Cause:
Twisted O-ring

Action:
If there is a complaint, check the respective O-ring of the affected refrigerant line and replace it if necessary.
Installation

Position:
Installation location for air-conditioning compressor / refrigerant lines (shown on the Porsche Cayenne)
Jan 27, 2026

Page 2 of 7
AfterSales
Service
Technical Information
174/23 ENU
8734
8
Required parts and materials

Parts Info:
Part No.
Designation

– Location
Number
N 10414402
⇒ Cheese head bolt with multiple-tooth head M8 x 28

– Refrigerant line to compressor
1 piece
95557374903
⇒ O-ring, 23.8 x 2.4

– Refrigerant line between compressor and evaporator
1 piece
or

Only for Panamera (971)

99970755741
⇒ O-ring 11.00 x 2.50 NX

– Refrigerant line between compressor and condenser
1 piece
or

Only for Cayenne (9YA / 9YB)

95557374901
⇒ O-ring, 11,0 x 2.5

– Refrigerant line between compressor and condenser
1 piece
Additional parts required for Cayenne (9YA / 9YB) with Porsche Dynamic Chassis Control (PDCC)

(M-No. 1P7)

PAF00072900
⇒ Hexagon socket head bolt, M8 x 20

– Front section of front underbody cover
3 pieces
or

Additional parts required for Cayenne (9YA / 9YB) with engine protective plate (M-No. 1SF)

N 10082912
Materials:
⇒ Hexagon screw (instrument cluster), self-locking

M6 x 16

– Front engine protection on holder
3 pieces
Required materials (usually already available in the Porsche Center)

Part No.
Designation

– Location
Quantity
Vehicles with refrigerant R1234yf
AfterSales
Jan 27, 2026

Page 3 of 7
8
Service

8734
ENU
Technical Information
174/23
9A757390010
⇒ Refrigerant compressor oil 1234yf

– Air-conditioning system
As required
....
⇒ Refrigerant 1234yf

– Air-conditioning system
As required
Vehicles with refrigerant R134a

00004330579
⇒ Refrigerant compressor oil R134a

– Air-conditioning system
As required
....
⇒ Refrigerant R134a

– Air-conditioning system
As required
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. battery charger 90 A.VAS 5908 - battery charger 90 A

Torque wrench, 2-10 Nm (1.5-7.5 ftlb.), e.g., V.A.G 1783 - Torque wrench, 2-10 Nm (1.5-7.5 ftlb.)

Torque wrench, 20-100 Nm (15-74 ftlb.), e.g., VAS 5820 - Torque wrench, 20-100 Nm (15-74 ftlb.)

Air conditioning service unit for R1234yf, e.g., VAS 581 001A - air-conditioning service unit R1234yf

or air conditioning service unit for R134a, e.g., VAS 6746A - air-conditioning service station R134a

VAS 6122 - Engine plug set
Checking refrigerant compressor oil loss

Work Procedure: 1
Jan 27, 2026

Page 4 of 7
Remove front underbody cover.
⇒ Workshop Manual '519219 Removing and installing cover for front underbody cover'
2
Remove front left wheel housing liner.

For procedure, see: ⇒ Workshop Manual '505619 Removing and installing wheel housing liner front'
3
Check and evaluate refrigerant compressor oil loss on the flange of the refrigerant line for the

compressor - evaporator and refrigerant line for the compressor - condenser on the air-conditioning

compressor. ⇒ Oil loss on air-conditioning compressor
AfterSales
Service
Technical Information
174/23 ENU
8734
8
Oil loss on air-conditioning compressor

Assessment

( )
✗)

(✗
Action
No refrigerant compressor oil loss can be

Þ Oil loss on air-condidetected on flange ⇒

tioning compressor -1- or air-conditioning

Þ Oil loss on air-conditioning

compressor ⇒

compressor -2-.

Refrigerant compressor oil loss can be detected

Þ Oil loss on air-conditioning

on flange ⇒

compressor -1- or air-conditioning compressor

Þ Oil loss on air-conditioning compressor -2-.

⇒

⇒ Flange refrigerant line leak
AfterSales
Locate the complaint elsewhere.

End of test.

Continue with:

⇒ Technical Information '505619 Follow-up

actions'

Replace the O-ring of the affected refrigerant

line.

Continue with:

⇒ Technical Information '505619 Replacing

O-ring refrigerant line on air-conditioning
Jan 27, 2026

Page 5 of 7
8
Service

8734
ENU
Technical Information
174/23
compressor'
Flange refrigerant line leak
Replacing O-ring refrigerant line on air-conditioning compressor

Work Procedure: 1
Replace the O-ring of the affected refrigerant line on the air-conditioning compressor.

For procedure, see:

⇒ Workshop Manual '874319 Removing and installing refrigerant line between compressor and

condenser'

⇒ Workshop Manual '874519 Removing and installing compressor/evaporator line (section from

air-conditioning compressor to internal heat exchanger)'
Follow-up actions

Work Procedure: 1

2
Install the front left wheel housing liner.

For procedure, see: ⇒ Workshop Manual '505619 Removing and installing wheel housing liner front'

Install front underbody panelling.
⇒ Workshop Manual '519219 Removing and installing cover for front underbody cover'
Working position and PCSS encryption (Panamera)

Labor position:

APOS
Labor operation
I No.
87450100
Checking refrigerant compressor oil loss
87454910
Replacing O-ring refrigerant line on air-conditioning

compressor

PCSS encryption:
Location (FES5)
87340
Air-conditioning compressor
Damage type (SA4)
5000
Leaks
Jan 27, 2026

Page 6 of 7
AfterSales
Service
Technical Information
174/23 ENU
8734
8
Working position and PCSS encryption (Cayenne)

Labor position:

APOS
Labor operation
I No.
87450100
Checking refrigerant compressor oil loss
87454900
Replacing O-ring refrigerant line on air-conditioning

compressor

PCSS encryption:
Location (FES5)
87340
Air-conditioning compressor
Damage type (SA4)
5000
Leaks
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 27, 2026

Page 7 of 7

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