Service bulletins for the 2023 Mercedes-Benz AMG GT
A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.
185 on file from NHTSA, as of 2026-10-19.
About P0128 on the 2023 Mercedes-Benz AMG GT: what the code means, and the bulletins and recalls about the same components.
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Only bulletins with trouble code: P0128 are shown. Show all
| LI20.10-P-072886 | 2026-07-27. Service bulletin. ENGINE. Complaint Check Engine Light ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and/or stored in the ME (N3/10). There are no drivability concerns related to this complaint. Cause Root cause varies Remedy Prior to performing any repairs for this complaint: With a cold engine, pressurize the high temp coolant circuit and while it's under pressure, release the cap on the low temp coolant circuit and check if the pressure drops right away or not. If the pressure drops, the lower coolant hoses are swapped. Correct this, fill, bleed and test drive the vehicle. If the complaint returns, then continue with the steps below. IMPORTANT: Use VMI to check for the following emission extended warranty –> Engine Thermostat (incl. software update) MY19-23, Various Models and Platforms (167, 190, 205, 213, 217, 222, 223, 232, 253, 290, 463) If the vehicle is covered under the above emission extended warranty, please perform steps outlined in the accompanying NCU prior to those outlined in this document. If vehicle is not covered under the above emission extended warranty or the complaint continues to occur, then proceed as follows: Check for available software updates to the ME (N3/10). If updated software is available, perform the update, clear the DTC and the perform each of the "WARM START" and "COLD START" test drives listed below twice. If the code does not re-appear then release the vehicle. If there is no new software available OR the DTC returns after the test drives then perform the following steps: • Drain the coolant through a fine mesh sieve and check for signs of debris. Additionally, inspect the coolant reservoir for debris. If any debris is found take pictures of the reservoir and the mesh filter and "flush" the system at least 2-3 times to clear as much of the debris as possible • Replace the thermostat and bleed the system as outlined in AR20.00-P-1142-04A, evacuate the system for 20-30 minutes instead of the 5 minutes specified in step 22 • NOTE: Please use all the tools specified in the AR document. The DTC will continue to populate if the circuit is not properly bled • NOTE: There are two valid thermostats to choose from in the parts section of this LI. Please verify which PN is applicable for the vehicle being worked on via XENTRY Parts Information • After bleeding the system clear the DTC and perform each of the "WARM START" and "COLD START" test drives listed below twice. If the DTC does not reappear after the tests, release the vehicle If the ME (N3/10) software is up to date, the thermostat has already been replaced, and the complaint persists open a TIPS case and attach the following documents: • Initial quick test • ME (N3/10) control unit log • The results of an R48 test from a “yes” response and from a “no” response • Pictures of the coolant reservoir and mesh sieve (mentioned above) WARM START · Begin with the engine coolant temperature at approximately 50 degrees C · Activate the AC system, if defrost is not in use open the windows · Drive the car normally until a coolant temperature of 75 degrees C is achieved · Depress the accelerator pedal 50% for ~5 seconds (partial acceleration) · Let off the accelerator pedal and let the car coast for ~10 seconds · Continue to drive the car normally COLD START · Drive for ~7 miles (normal driving) · Shut off the engine in a parking lot (or similar), wait 30 seconds, then restart and continue driving · Depress the accelerator pedal 50% for ~5 seconds (partial acceleration) · Let off the accelerator pedal and let the car coast for ~10 seconds · Continue to drive the car normally |
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| LI20.10-P-072886 | 2026-04-27. Service bulletin. ENGINE. Complaint CEL ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and stored in the ME (N3/10). There are no drivability concerns related to the complaint. Cause Root cause varies Remedy Prior to performing any repairs for this complaint: With a cold engine, pressurize the high temp coolant circuit and while it's under pressure, release the cap on the low temp coolant circuit and check if the pressure drops right away or not. If the pressure drops, the lower hoses are swapped. Correct this, fill, bleed and test drive the vehicle. If the complaint returns, then continue with the steps below. IMPORTANT: Use VMI to check for emission extended warranty – Engine Thermostat (incl. software update) MY19-23, Various Models and Platforms (167, 190, 205, 213, 217, 222, 223, 232, 253, 290, 463) If the vehicle is covered under an emission extended warranty, Please perform steps outlined in the NCU for repairs. If vehicle is not covered under an emission extended warranty, then proceed as follows: Check for available software updates to the ME (N3/10). If updated software is available, perform the update, clear the DTC and the perform each of the "WARM START" and "COLD START" test drives listed below twice. If the code does not re-appear then release the vehicle If there is no new software available OR the DTC returns after the test drives then perform the following steps: • Drain the coolant through a fine mesh sieve and check for signs of debris. Additionally, inspect the coolant reservoir for debris. If any debris is found, flush the system several times to clear as much of the debris as possible • Replace the thermostat and bleed the system as outlined in AR20.00-P-1142-04A, evacuate the system for 20-30 minutes instead of the 5 minutes specified in step 22 • NOTE: Please use all the tools specified in the AR document • NOTE: There are two valid thermostats to choose from in the parts section of this LI. Please verify which PN is applicable for the vehicle being worked on via XENTRY Parts Information • After bleeding the system clear the DTC and perform each of the "WARM START" and "COLD START" test drives listed below twice. If the DTC does not reappear after the tests, release the vehicle If there is no new software available, the thermostat has already been replaced, and the DTC returns open a TIPS case and attach the following documents: • Initial quick test • ME (N3/10) control unit log • The results of an R48 test from a “yes” response and from a “no” response WARM START · Begin with the engine coolant temperature at approximately 50 degrees C · Activate the AC system, if defrost is not in use open the windows · Drive the car normally until a coolant temperature of 75 degrees C is achieved · Depress the accelerator pedal 50% for ~5 seconds (partial acceleration) · Let off the accelerator pedal and let the car coast for ~10 seconds · Continue to drive the car normally COLD START · Drive for ~7 miles (normal driving) · Shut off the engine in a parking lot (or similar), wait 30 seconds, then restart and continue driving · Depress the accelerator pedal 50% for ~5 seconds (partial acceleration) · Let off the accelerator pedal and let the car coast for ~10 seconds · Continue to drive the car normally |
| LI20.10-P-072886 | 2026-02-13. Service bulletin. ENGINE. Complaint CEL on with Code P012800 "The Coolant Temperature is Below the Specified Temperature" Cause Under investigation. This is not an issue that affects drivability or performance and is not a safety concern. The vehicle remains safe to operate with this code, but the measures listed in the "Remedy" section are recommended. Remedy 1. Use VMI to check for Emission Extended Warranty – Engine Thermostat (incl. software update) MY19-23, Various Models and Platforms (167, 190, 205, 213, 217, 222, 223, 232, 253, 290, 463) 2. If the vehicle is covered under the Emission Extended Warranty, Please perform steps outlined in the NCU for repairs. 3. If vehicle does not fall into the covered area of the Extended Warranty please check for Software updates to the ME control unit and then proceed with "Remedy Instructions" in attachments. Due to formatting issues please see "remedy instructions" in attachments |
| LI20.10-P-072886 | 2026-01-06. Service bulletin. ENGINE. Complaint CEL on with Code P012800 "The Coolant Temperature is Below the Specified Temperature" Cause Under investigation. This is not an issue that affects drivability or performance and is not a safety concern. The vehicle remains safe to operate with this code, but the measures listed in the "Remedy" section are recommended. Remedy 1. Use VMI to check for Emission Extended Warranty – Engine Thermostat (incl. software update) MY19-23, Various Models and Platforms (167, 190, 205, 213, 217, 222, 223, 232, 253, 290, 463) 2. If the vehicle is covered under the Emission Extended Warranty, Please perform steps outlined in the NCU for repairs. 3. If vehicle does not fall into the covered area of the Extended Warranty please proceed with "Remedy Instructions" in attachments. Due to formatting issues please see "remedy instructions" in attachments |
| EW-EngineThermSW | 2024-01-03. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. In our continuing efforts to assure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA, LLC ("MBUSA") is extending the warranty coverage on the engine thermostat (including software update) installed in certain Model Year ("MY") vehicles (with engines M176, M177, M178) listed below from the original New Vehicle Limited Warranty of 4 years/50,000 miles to 15 years/150,000 miles (whichever occurs first), due to the following condition: In the affected vehicles, the sealing ring in the engine thermostat could detach, causing a delay in the heating of the engine coolant. This may also cause the check engine Malfunction Indicator Lamp ("MIL") to illuminate. Please follow the work instructions added to this NCU to remedy the issue. Please be advised that all repairs being claimed under this extended warranty must have a quick test uploaded with the following fault code information and may be audited. P012800 - Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) All repairs found to be functioning properly or without proper documentation will be returned and the claim debited in full. Only the following damage codes and parts may be claimed for the aforementioned repairs: Damage Code(s): 20102 - Insert, coolant thermostat o 52 - Does not operate correctly o 41 - Hard closing 20103 - Housing/cover, coolant thermostat o 73 - Electrical fault 2030T - Heating element, coolant thermostat o 53 - Insufficient effect/power o 73 - Electrical fault |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.