# Troubleshooting

This chapter explains how you can troubleshoot a specific problem, such as abnormal LED activity or no system power, when you power up the router. It contains the following sections:

- Diagnosing Problems
- Troubleshooting Power Failures
- Understanding Status LEDs to Troubleshoot
- Monitoring Temperatures of Modules
- Resetting Line Modules and SRP Modules
- Double-Bit Errors on SRP Modules