2021 Mercedes-Benz AMG GT Misfire DTCs and CEL

Overview of the Issue

Owners of the 2021 Mercedes-Benz AMG GT may encounter a "check engine light (CEL)" illuminated on their dashboard, accompanied by symptoms such as the engine running roughly or a noticeable loss of power. This XENTRY Tips document, LI07.61-P-070707, addresses these concerns, including Mercedes-Benz AMG GT misfire DTCs, indicating that multiple causes can lead to these conditions. This bulletin, version 14, was released on May 21, 2024, and applies to the AMG M17x.xxx Engine Group. The reason for its latest update was a "Tool Update."

Symptoms of Misfire DTCs

If your 2021 Mercedes-Benz AMG GT is affected by these misfire DTCs, you might observe the following symptoms related to power generation and engine management:

• Engine running roughly/shakes: The engine may feel unstable, vibrate excessively, or produce unusual noises during operation.
• Check Engine Light (CEL) on: The indicator lamp for engine diagnosis will be lit on the instrument cluster.
• Loss of power/poor output: The vehicle might experience reduced engine performance, sluggish acceleration, or a general lack of responsiveness.

These symptoms are typically associated with "combustion misfiring" within the engine.

Diagnostic Trouble Codes (DTCs)

Technicians diagnosing the issue will likely find one or more of the following diagnostic trouble codes (DTCs) stored in the engine control unit (N3/10 - Motor electronics 'MED1775' or 'MRG1AMGV8'). These codes specifically point to various "combustion misfiring" conditions across different cylinders and engine types:

Code	Fault Text	Control Unit	Engine Type
P036300	Injector shutoff was activated due to a combustion misfire.	N3/10	M176/M177/M178
P030885	Combustion misfiring of cylinder 8 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030800	Combustion misfiring of cylinder 8 has been detected.	N3/10	M176/M177/M178, M177
P030785	Combustion misfiring of cylinder 7 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030700	Combustion misfiring of cylinder 7 has been detected.	N3/10	M176/M177/M178, M177
P030685	Combustion misfiring of cylinder 6 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030600	Combustion misfiring of cylinder 6 has been detected.	N3/10	M176/M177/M178, M177
P030585	Combustion misfiring of cylinder 5 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030500	Combustion misfiring of cylinder 5 has been detected.	N3/10	M176/M177/M178, M177
P030485	Combustion misfiring of cylinder 4 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030400	Combustion misfiring of cylinder 4 has been detected.	N3/10	M176/M177/M178, M177
P030385	Combustion misfiring of cylinder 3 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030300	Combustion misfiring of cylinder 3 has been detected.	N3/10	M176/M177/M178, M177
P030285	Combustion misfiring of cylinder 2 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030200	Combustion misfiring of cylinder 2 has been detected.	N3/10	M176/M177/M178, M177
P030185	Combustion misfiring of cylinder 1 has been detected. There is a signal above the permissible limit value.	N3/10	M176/M177/M178
P030100	Combustion misfiring of cylinder 1 has been detected.	N3/10	M176/M177/M178, M177
P030022	Combustion misfiring has been detected. The signal amplitude is greater than the maximum amplitude.	N3/10	M176/M177/M178, M177
P030027	Combustion misfiring has been detected. The signal change rate is above the permissible limit value.	N3/10	M176/M177/M178
P031600	Combustion misfires were detected at engine start.	N3/10	M177
P030021	Combustion misfiring has been detected. The signal amplitude is less than the minimum amplitude.	N3/10	M177
P030000	Combustion misfiring has been detected.	N3/10	M177

These codes indicate that the engine's control unit has detected an issue with the combustion process in one or more cylinders, or a general misfire condition. Addressing these Mercedes-Benz AMG GT misfire DTCs is crucial for vehicle performance and longevity.

Potential Causes

The document indicates that the underlying cause for these misfire conditions and the illumination of the check engine light can be attributed to "Multiple Causes." This suggests that a thorough diagnostic process is required to pinpoint the specific root of the problem, as it may not be a single component failure.

Remedy and Repair Procedure

The detailed remedy for these misfire DTCs is provided in separate "Remedy Instructions" attachments to the original bulletin. Technicians are directed to consult these specific documents for the step-by-step repair process. It is important to note that for MY19+ G63 models, an alternate solution may be available. Furthermore, technicians should reference bulletin LI07.61-P-076755 before performing any steps outlined in this specific LI07.61-P-070707 document.

Required Parts and Diagnostic Attachments

To assist with diagnosis and repair of these Mercedes-Benz AMG GT misfire DTCs, several attachments and a specific part are mentioned:

Required Parts:

• Ignition Coil: Part number A1779060206 (Quantity: 8)

Diagnostic and Repair Attachments:

• BR253_ground_points.pdf: Describes 253 Ground Points
• C_Class Ground Points LS1.pdf: Describes 205 Ground Points
• facelift 463 ground check.pdf: Describes 463 Ground Points
• Ground points LS2_BR213_englx.pdf: Describes 213 Ground Points
• GT Ground Check.pdf: Describes 190 Ground Points
• Ground Points LS2_BR222 (002).pdf: Describes 222 Ground Points
• Massestellen LS2_BR290_engl.pdf: Describes 290 Ground Points
• Fault Counter Instructions.pdf: Provides instructions for fault counters
• Smoke Check.pdf
• Misfire LI Revision v5.pdf

These attachments provide critical information for identifying ground points, performing fault counter checks, and other diagnostic procedures necessary to resolve the misfire issues.

NHTSA ID

Source: NHTSA ID 10255394