Symptoms of a timing chain failure may include the following:

1. Difficulty starting the engine: Due to the malfunction of the valve train, the engine may be difficult to start or require multiple attempts.

2. Power loss: Due to inaccurate opening and closing times of the intake and exhaust valves, the engine's cylinders may not be able to fully burn fuel, resulting in power loss.

3. Increased fuel consumption: Due to incomplete combustion, the engine requires more fuel to maintain operation, resulting in increased fuel consumption.

4. Increased noise: A worn or incorrect timing chain may cause the engine to run unevenly and produce additional noise.

5. Cooling system failure: If a timing chain failure causes the water pump to not work properly, it may affect the engine's cooling system and cause overheating.

6. The fault warning light is on: The diagnostic system of some vehicles may light up the relevant fault warning light when a timing chain failure is detected.