The vehicle speed and gear position meet the conditions for the lock-up clutch to engage, but the lock-up clutch still does not engage, and fuel consumption is high.
- Troubleshooting:
① Automatic transmission fluid temperature sensor faulty;
② Throttle position sensor faulty;
③ Lock-up solenoid valve faulty or short circuit/open circuit;
④ Lock-up control valve faulty;
⑤ Lock-up clutch in the torque converter damaged.