Buick: Cooling

This bulletin applies to 2020-2022 Buick Encore GX vehicles. The MIL may be on with DTC P3075 (engine coolant flow too low) set in the ECM. This condition is caused by low coolant or air trapped in the cooling system. Make sure that the vehicle is updated with the most current software level. 

Pressure test the cooling system to confirm that there are no leaks. If no leaks are present or if leaks have been repaired, refer to the latest cooling system draining and filling procedure for coolant fill and bleeding procedures. 

(Note: Once the engine is started after the coolant service fill procedure, DTC P3075 may reset until all air is properly purged.)

Once completed, clear any DTCs and operate the vehicle under the conditions for running the trouble code per SI. Note that P3075/P3076 can detect coolant flow-based failures. 

The intrusive diagnostic test will run once per ignition cycle if all enable conditions are met per SI. The test will run the coolant pump at roughly 4,000 rpm for 15 seconds and evaluate the pump motor AC current to be within the expected range. 

The coolant pump AC current feedback will be lower if the cooling system is leaking or low on coolant. 

Using GDS, confirm that P3075 has run and passed in the current drive cycle to ensure that the diagnostic has executed and no fault is detected. If the vehicle returns for the second time with DTC P3075, replace the coolant pump assembly.