No. 2221.1

8
Bulletin #: 2221.1
Advanced Technical Information
Part ID: 8274
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
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)
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.
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Bulletin #: 2221.1
Advanced Technical Information
Part ID: 8274
8
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.
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Bulletin #: 2221.1
Advanced Technical Information
Part ID: 8274
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Service Information
A software solution is currently in development. Until a permanent solution is available, please perform the following:
1.
Create a VAL to document the occurrence of TME fault P26B100.
2.
For MY20-23 only: Check the TME software version Thermal Management (TME) --> Extended 			
		
Identifications. If the TME is at software version 0304, please update the TME to the latest software version
		
as instructed in “TI - 9YA 9YB 8 193/22 Check Engine Warning Light Active / Fault Memory Entry 			
		
“P26B100/00CB24” in the Thermal Management Control Unit (TME): Reprogramming Control Unit”
3.
Verify proper routing of the coolant lines by inspection.
4.
With the front climate controls set to 72° F/ 22° C, A/C off, verify proper operation of he valve UVW3 via 		
		the Actual values:
		
Thermal Management (TME) → Actual Values → High-temperature circuit → Directional-control valve for 		
		
high-temperature circuit for interior heating (UVW3)
		
a.
The actual value should display “actuated” if the coolant temperature given by the actual value 		
			
“Combustion engine coolant temperature (via CAN)” is less than 40° C.
		
b.
The actual value should display “not actuated” if the coolant temperature given by the actual value 		
			
“Combustion engine coolant temperature (via CAN)” is greater than 40° C.
5.
Create a VAL to document any TME software updates.
To reduce the likelihood of the fault TME P26B100 occurring, the customer may activate interior preconditioning 		
prior to departure. This may be done either via a Departure Timer in the Hybrid menu in the PCM, or via the
My Porsche smartphone app.
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.
©2023 Porsche Cars North America, Inc.
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March 16, 2023
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Bulletin #: 2221.1
Advanced Technical Information
Part ID: 8274
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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.
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