OBD Code P26F400: Coolant Pump “C” Control Circuit Open – Active/Static in Skoda & VW Cars

Understanding OBD Code P26F400 in Skoda, VW, Audi

The P26F400 error code, commonly found in Skoda, Volkswagen (VW), and Audi vehicles, refers to:
“Coolant Pump ‘C’ Control Circuit Open – Active/Static.”

This means the vehicle’s control unit has detected an open circuit in the coolant pump “C” wiring or signal. It often affects vehicles experiencing cooling system inefficiencies or irregular temperature behavior.

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Commonly Affected Models

• Skoda Octavia, Skoda Superb, Skoda Kodiaq
• Volkswagen Tiguan, VW Golf, VW Passat
• Audi A3, Audi Q5
• Seat Leon, Seat Ibiza

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Related Fault Codes and Databus Errors

In many cases, P26F400 is accompanied by other faults like:

• U1123 Skoda Octavia
• U1123 Volkswagen, U1123 Audi, VW U1123 00
• Skoda Error P26F400
• DTC U1123, Databus Error Value Received Meaning
• Skoda B104B31 – Key No Signal
• Skoda P1612, P1889 Skoda, P177b Skoda, P177c VW

These errors often point toward CAN bus communication failures, which can affect multiple ECUs, including those responsible for coolant pump operations.

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Causes of Code P26F400

• Faulty Coolant Pump “C”
• Damaged or corroded wiring/connector
• ECU software issue
• Malfunctioning Databus (CAN Bus)
• Relay or fuse issue

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Symptoms of P26F400 & Related U1123 Errors

• Engine overheating
• Fans not engaging
• Inconsistent temperature readings
• Dashboard warning lights
• Multiple fault codes including U1123 fault code VW or U112300 Databus Error Value Received

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✅ How to Fix P26F400 Error

1. Visual Inspection: Check the coolant pump wiring and connectors.
2. Scan for Codes: Use OBD-II tool to confirm related errors like U1123 VW Tiguan, P26F400 Skoda, or U112300 - Databus Error Value Received.
3. Coolant Pump Test: Replace if non-functional.
4. Software Reset: Reset ECU using diagnostic software.
5. Professional Diagnosis: For recurring U1123 data bus errors, consult a technician.

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Internal Linking Suggestions:

• Fix U1123 Databus Error in Skoda Vehicles
• Throttle Valve Error Code P1545 Explained
• Component Protection Active – U110100 Guide

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Conclusion

OBD Code P26F400 and associated U1123 fault codes can seriously impact your vehicle’s cooling performance and engine reliability. Regular diagnostics and preventive maintenance help avoid complex electronic communication issues across modules.

Stay informed, drive safe, and don’t ignore those warning lights!