Buick Hideo fault code 89, what if the coolant has just been replaced?

It may be the fault of the throttle or the fault of the throttle harness, because the real car can't be seen, so the fault can't be accurately judged. I suggest you contact the local 4S shop for inspection and maintenance.

The thermostat often breaks down for the following reasons: 1. Due to the prolonged warm-up time, the car runs at low water temperature, and the combustion gas and water condensed on the cylinder wall form acidic substances to corrode the cylinder; 2. Liquid fuel and moisture scour the lubricating oil film on the cylinder wall and flow down the oil pan along the cylinder wall, diluting the oil in the lubricating system and causing the wear of the cylinder liner and piston parts; 3. If the cylinder block is defective, repair it with glue. If the engine temperature changes too much, the cylinder block will contract and expand frequently, leading to the failure of the diesel engine.