Malfunction Indicator Lamp (MIL) Illuminated – DTC P3075 Set – 2019-2022 Buick Cadillac Chevrolet GMC

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Service Bulletin Bulletin No.: 21-NA-257
Date: November, 2021
TECHNICAL
Subject: Malfunction Indicator Lamp (MIL) Illuminated – DTC P3075 Set
Brand: Model:
Model Year: VIN: Engine:
(1.3L,
2.0L, 2.7L)
Transmission:
from to from to
Buick Encore GX 2020 2022
— —
L3T
—
Cadillac
CT4 2020
2022
L3B, LSY
CT5 2020 LSY
XT4 2019 LSY
XT5 2020 LSY
XT6 2020 LSY
Chevrolet
Blazer 2019 2022 LSY
Silverado
1500
(New Model)
2019 2019 L3B
Silverado
1500 2020
2022
L3B
Trailblazer 2021 L3T
GMC
Acadia 2020 2022 LSY
Sierra 1500
(New Model) 2019 2019 L3B
Sierra 1500 2020 2022 L3B
Involved Region or Country
North America, Europe, Russia, Middle East, Israel, Palestine, Chile, Colombia, Ecuador,
Paraguay, Peru, Uruguay, Japan, Cadillac Korea (South Korea), Thailand, Australia/New
Zealand
Condition
Some customers may comment that the MIL is illuminated.
Some technicians may find DTC P3075 (Engine Coolant Flow Too Low) set in the Engine
Control Module (ECM).
Cause This condition may be caused by low coolant or air trapped in the cooling system.
Page 2 November, 2021 Bulletin No.: 21-NA-257
Correction
Note: For 2019 MY vehicles equipped with the 2.7L (L3B), refer to Service Bulletin #
19-NA-149 first to verify if the vehicle has the most current level of software.
If you encounter a vehicle with the above condition, complete the following steps:
Important: Do not replace the coolant pump assembly at this time.
1. Pressure test the cooling system to confirm no coolant leaks are present. Any leaks
in the cooling system should be repaired using Service Information.
2. Once the coolant leak has been repaired, refer to the latest Cooling System
Draining and Filling procedure in SI for coolant fill and bleeding procedures.
Note: Once the engine is started after the coolant service fill procedure, it will be
possible that 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.
3. Once completed, clear any DTCs and operate the vehicle under the conditions for
running the trouble code per SI.
Note: The 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 intrusive diagnostic will run the coolant pump at roughly 4000
rpm for 15 seconds and evaluates the pump motor AC current to be within
expected range.
– The coolant pump AC current feedback will be lower if the cooling system is
leaking or low on coolant.
4. Using GDS, confirm the P3075 has run and passed in the current drive cycle to
ensure the diagnostic has executed and no fault is detected before releasing the
vehicle back to the customer.
If the vehicle returns for a second time with DTC P3075, replace the coolant pump
assembly. Parts will be returned to the Warranty Parts Center.
Parts Information
No parts are required for this repair.
Warranty Information
For vehicles repaired under the Bumper-to-Bumper
coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH)
for coverage information.
Labor
Operation
Description Labor Time
4087038* Pressure Test the Cooling
System
0.3 hr
*This is a unique Labor Operation for bulletin use only.
Version 1
Modified Released November 12, 2021

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