Description:

This diagnostic trouble code, ECU 000647.07, is set when the ECU detects a fault in the engine fan speed decrease circuit, indicating that Fan Output Drive 2 (fan speed decrease) circuit is either shorted or open.

Reaction:

The ECU may limit the functionality of the fan speed control to prevent damage or malfunction due to the faulty circuit.

Recommendations:

• Inspect Fan Speed Decrease Circuit: Check the wiring and connectors for Fan Output Drive 2 for signs of damage, short circuits, or disconnections.
• Measure Circuit Continuity: Use a multimeter to measure the continuity in the circuit to identify any breaks or shorts.
• Repair or Replace Faulty Wiring: Fix any identified issues by repairing or replacing damaged wires or connectors.
• Verify Fan Speed Control: Test the fan speed control functionality after repairs to ensure it operates correctly and the circuit is stable.
• Reset ECU and Conduct Tests: After addressing the issue, reset the ECU and perform system tests to confirm that the fan speed decrease circuit is functioning correctly and no further errors are detected.

Note:

Maintaining the integrity of the fan speed control circuits is essential for proper engine cooling and overall vehicle performance. Regular inspections can help prevent such issues from arising.