what does it mean if my Toyota Corolla E170 (2013-2019) has a C-1261 code?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the 12V battery to ensure safety.
• Allow the vehicle to sit for at least 30 minutes to ensure the hybrid system is completely powered down.

2. Inspect and Repair Battery Connections

• Tools Required: Socket set, torque wrench
• Remove the cover from the hybrid battery to access the connections.
• Check all terminals for tightness; tighten any loose connections to manufacturer specifications (usually around 10-12 ft-lbs).
• Clean any corrosion found on terminals using a wire brush and a solution of baking soda and water.

3. Test Hybrid Battery Voltage

• Reconnect the negative terminal of the 12V battery.
• Use a multimeter to measure the voltage of the hybrid battery.
• Voltage should be within the manufacturer’s specified range (typically 200-300V for hybrid batteries).
• If voltage is low, consider replacing the hybrid battery.

4. Inspect Hybrid Battery Cooling System

• Remove any debris from the hybrid battery cooling vents and fans.
• Test the operation of the cooling fan by running the vehicle and ensuring the fan activates when the battery temperature rises.
• Replace any non-functioning cooling fans.

5. Update or Replace Hybrid Vehicle Control Module

• Check for any software updates for the HVCM through the manufacturer's service portal.
• If no updates solve the issue, consider replacing the HVCM.