8

Bulletin #: 2215

Advanced Technical Information

Part ID: 8274

Panamera E-Hybrid – Thermal Management Control Unit Fault P26B100 Causes
Check Engine Light
Vehicles Affected
Models

Model Year

Model Type

VIN Range

Vehicle-Specific Equipment

Panamera

As of 2019 up to 2020

97ABE1
97AFH1
97BBE1
97BFH1
97CBE1
97CFH1

N/A

E-Hybrid

Panamera

2021

97ABX1
97ADZ1
97AFT1
97BBX1
97BDZ1
97BFT1
97CBX1
97CDZ1
97CFT1

N/A

E-Hybrid

Revision History
Revision

Release Date

Changes

0

May 31, 2022

Original document

Condition
The customer complains of the presence of a check engine light in the instrument cluster.
The workshop finds fault code P26B100 – Directional-control valve for high-temperature circuit (UVW3) –
function implausible stored in the Thermal management control unit (TME).

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Bulletin #: 2215

Advanced Technical Information

Part ID: 8274

8

Technical Background
There is a possibility that the aforementioned fault code sets due to the TME diagnostics not being robust enough.
While the combustion engine temperature is < 40 °C (104 °F), the changeover valve UVW3 will remain closed
such that the passenger compartment is heated via the HV interior heater on the small coolant circuit. During small
circuit operation, the absolute value of the temperature difference between temperature sensors TW11 and TW12
should be > 7 K (> 7 °C).

Large
circuit
Small
circuit

Figure 1: Panamera E-Hybrid Cooling Circuit
Once the combustion engine temperature is within the range of 40 to 60 °C (104 to 140 °F), the valve UVW3 opens
and the coolant circuit is operating on the large circuit that includes the combustion engine circuit. During large
circuit operation, the absolute value of the temperature difference between temperature sensors TW11 and TW12
should be < 7 K (< 7 °C).
During short operation of the combustion engine after cold start, the coolant temperature may rise to the range of
40 to 60 °C (104 to 140 °F) and valve UVW3 may or may not open. There is a possibility that the valve remains
closed and waste heat from the engine continues to heat up temperature sensor TW12. If the valve is closed and
sufficient waste heat exists, the absolute value of the temperature difference between sensors TW11 and TW12
may fall below the 7 K (7 °C) threshold. Such conditions may cause the TME to believe valve UVW3 is stuck in an

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Bulletin #: 2215

Advanced Technical Information

Part ID: 8274

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incorrect position (e.g., closed when it should be open), despite the system functioning properly. This misdiagnosis
may set fault code P26B100 in the TME.

To address this concern, please perform the following:
1.
Open a PCSS job and create a VAL.
2.
In the VAL, find TME fault P26B100 and open the fault information. Check the value of 13_Fault display in
the instrument cluster. If this value is “on”, this fault is the cause of the check engine light.

3.
4.
5.

Find the Thermal management control unit (TME) in the “Overview” tab in the PIWIS Tester and select it.
Navigate to the “Extended Identifications” tab to view the control unit information. Check the current
software level in the TME. The current SW level should correspond to one of the two Factory SW Levels
given in Table 1 below.
Please navigate to the Overview tab in the PIWIS Tester and select “Additional menu” on the bottom toolbar.
Select “Campaign” from the list and use the Programming Code given in Table 1 below.
Model Year

Factory SW
Level

Programming
Code

SW Level after
Programming

2019

0303

G2T8E

0305

2020

0303

G2T8E

0305

2021

0304

G2T8E

0305

Table 1: TME Software Updare Information
6.
7.

After programming is complete, navigate to the “Extended identifications” tab for the TME. Verify that the
control unit successfully updated to the Final SW Level given in Table 1. Please also create an “After repair”
VAL.
If the fault persists after updating the TME to SW Level 0305, please ensure the coolant system is properly
filled and bled and that there are no electrical or mechanical faults with valve UVW3 or with temperature
sensors TW11 and TW12. Please also check coolant hoses for proper routing and/or restrictions.

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Bulletin #: 2215

Advanced Technical Information

Part ID: 8274

8

Warranty
As always, please document the repair completely in PQIS.
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 operations:
03350000
On board diagnostic
19292565
Thermal management control unit program

Search Items
Panamera, 971, 97A, 97B, 97C, check engine light, TME, thermal management, P26B100, 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.

K11468
©2022 Porsche Cars North America, Inc.

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