Bulletin #: 2221.4

Advanced Technical Information

Part ID: 8274

8

Cayenne E-Hybrid – Thermal Management Fault P26B100 Causes Check Engine Light
Vehicles Affected
Models

Model Year

Model Type

VIN Range

Vehicle-Specific Equipment

Cayenne

As of 2019 up to 2023

9YAAE1
9YACH1
9YADE1
9YBAE1
9YBCH1
9YBDE1

N/A

+0K3

Revision History
Revision

Release Date

Changes

0

August 3, 2022

Original document

1

March 16, 2023

Update of MY, Technical Background, Service Information

2

April 27, 2023

Update of Service Information

3

November 15, 2023

Update of Service Information

4

June 13, 2024

Update of Service Information

Condition
The customer complains of a check engine light. The light may be continuous or intermittent.
The workshop finds the fault P26B100 - Directional-control valve for high-temperature circuit (UVW3) – function
implausible stored in the Thermal Management Control Unit (TME).
Area of Occurrence (DME, Instrument Cluster, etc.)
82740 – Directional-control valve (changeover valve UVW3)

AfterSales

June 13, 2024
Page 1 of 4

8

Bulletin #: 2221.4

Advanced Technical Information

Part ID: 8274

Technical Background
The aforementioned fault code may be caused by a misdiagnosis of the directional control value for the high
temperature circuit for interior heating (valve UVW3).
Under certain operating conditions, a lack of temperature difference between the engine coolant circuit and the
interior heating circuit may result in the TME diagnosing valve UVW3 as “stuck closed”, despite no mechanical fault
in the valve.

Figure 1 - Cayenne E-Hybrid Cooling Circuits

Valve UVW3 controls the direction of coolant flow based on engine temperature. The valve defaults to closed, such
that the high-temp circuit excludes the engine coolant circuit. During this “small-circuit” operation, the HV PTC
controls the temperature of the high-temp circuit to meet the heating and air conditioning demands of the
customer. Once the engine reaches 40° C, the valve opens (“large-circuit” operation) and the high-temp circuit uses
the engine heat instead of the HV PTC.
The status of UVW3 is diagnosed by the absolute value of the temperature difference between TW11 and TW12.
The TME expects this difference to be larger than 7° C while the valve is closed, but smaller than 7° C while the
valve is open. Certain operating conditions may cause the temperature difference to fall below 7° C while the valve
is closed. If this condition exists while the TME is performing diagnostics, the valve will be diagnosed as open,
although it is closed due to the engine temperature being less than 40° C.

AfterSales

June 13, 2024
Page 2 of 4

8

Bulletin #: 2221.4

Advanced Technical Information

Part ID: 8274

Service Information
1.

Please create a VAL to document the occurrence of the fault.

2.

If applicable, please complete Workshop Campaign WPR0. Please complete
this Campaign per the instructions in TI 177/23, before performing any other diagnosis work
for the subject fault code.
NOTE: Please reference the below table for the appropriate TME software and coding information after
completing Campaign WPR0. (Data Record Version can be found in the Extended Identifications tab for the
TME.)
Model Year

Engine Type

Target TME Software
Version

Target TME Data Record
Version

2019 (K)

V6 PHEV

0305

S012

V6 PHEV

0305

S011

2020 (L)

V8 PHEV

0305

S012

2021 (M)

V8 PHEV

0305

S011

2020 (L)
2021 (M)
2022 (N)
2023 (P)

2022 (N)
2023 (P)
3.

If the fault persists after performing WPR0, please continue with other means of diagnosis.

Warranty
As always, please document the repair completely in PCSS.
For this repair, please code the “cause” as follows:
Cause location:
82740 Directional-control valve
Cause symptom:
1613 No function occasionally
Use the following troubleshooting labor operation:
03350000
On board diagnostic
Additional labor operations may be claimed only as needed.

AfterSales

June 13, 2024
Page 3 of 4

Bulletin #: 2221.4

Advanced Technical Information

Part ID: 8274

8

Search Items
Cayenne, 9YA, 9YB, check engine light, TME, thermal management, P26B100, hybrid, E-Hybrid

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.

K12472
©2023 Porsche Cars North America, Inc.

AfterSales

June 13, 2024
Page 4 of 4