Cars Technical Articles - Low Coolant or Air Trapped in Engine Cooling System and DTC P3075 Set

Low Coolant or Air Trapped in Engine Cooling System and DTC P3075 Set

- Edited: Aug 19, 2022
- Popularity: 114 Views



Vehicles Affected:

  • 2020-2022 Buick Encore GX
  • 2020-2022 Cadillac CT4
  • 2020-2022 Cadillac CT5
  • 2019-2022 Cadillac XT4
  • 2020-2022 Cadillac XT5
  • 2020-2022 Cadillac XT6
  • 2019 2022 Chevrolet Blazer
  • 2019 2021 Chevrolet Malibu
  • 2019 Chevrolet Silverado 1500 (New Model)
  • 2020-2022 Chevrolet Silverado 1500
  • 2021-2022 Chevrolet Trailblazer
  • 2020-2022 GMC Acadia
  • 2019 GMC Sierra 1500 (New Model)
  • 2020-2022 GMC Sierra 1500


On some vehicles, the MIL is illuminated. The DTC P3075 (Engine Coolant Flow Too Low) is set in the Engine Control Module (ECM).


This condition may be caused by low coolant or air trapped in the cooling system.

Service Procedure:

TIP: For 2019 MY vehicles equipped with the 2.7L engine, refer to Bulletin 19-NA-149 to verify the vehicle has the most current level of software.

If these conditions are found, do not replace the coolant pump. Begin diagnosis by pressure testing the cooling system using the Cooling System Pressure Tester to check for any coolant leaks. Repair any leaks to the cooling system following the procedures in the appropriate Service Information.

GM Pressure Test

Once any coolant leaks have been repaired, follow the Cooling System Draining and Filling procedure in the appropriate Service Information to fill and bleed the cooling system. Once the engine is started after the coolant service fill procedure, DTC P3075 may reset until all the air is properly purged from the cooling system. At this point, codes should be cleared, the engine should be at operating temperature and the vehicle road tested to completely purge any remaining air from the cooling system.

After a road test, clear any DTCs and operate the vehicle under the conditions for running DTC P3075 following the Service Information procedures. DTC P3075/P3076 can detect coolant flow-based failures. The intrusive diagnostic test will run once per ignition cycle if all enable conditions are met. The coolant pump will run at roughly 4,000 rpm for 15 seconds and the pump motor AC current should be within the expected range. The coolant pump AC current feedback will be lower if the cooling system is leaking or low on coolant. Use an OBDII scanner to confirm that DTC P3075 test has run and passed in the current drive cycle.

If the vehicle returns a second time with DTC P3075 set, replace the coolant pump assembly.

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