P05F9

Symptoms

• The start-stop system does not work (the engine does not turn off when stopping)
• The indicator for disabling the start-stop system is on
• Check Engine Light Is On
• Other symptoms characteristic of a failure of the start-stop system

Causes

• Open or short circuit in the start-stop status signal circuit
• Malfunction of the start-stop system control unit
• Battery malfunction (AGM battery with reduced capacity)
• Problems with the CAN data bus
• Malfunction of the sensor used by the start-stop system

How to Fix

1. Read codes using a scanner, check for CAN bus codes
2. Check the AGM battery (special battery tester - capacity, internal resistance)
3. Inspect the connectors of the start-stop system control unit
4. Check the wiring of the status signal circuit for open circuit and short circuit.
5. Check the correct operation of the CAN bus between the blocks
6. Diagnose the start-stop system control unit

Related codes

Error P05F9 by Vehicle Brand