2021 Mercedes-Benz AMG GT P Button Malfunction TSB

Owners of the 2021 Mercedes-Benz AMG GT may experience a Mercedes-Benz AMG GT P button malfunction where the DSI selection lever module cannot be switched to the park position. This technical service bulletin (TSB) LI27.60-P-077704 outlines the complaint, potential causes, and a detailed remedy for this issue.

Symptoms

The primary symptom is the inability to switch the DSI selection lever module to the park position 'P' due to a malfunction of the 'P' button. Even with this issue, the vehicle is designed to automatically shift into park when the ignition is turned off or the driver's door is opened. Owners might also notice the general symptom of "Gear cannot be engaged" related to the automatic transmission's drive position selection function.

Fault Codes / DTCs

Technicians may find specific diagnostic trouble codes (DTCs) related to the Mercedes-Benz AMG GT P button malfunction:

| Code | Description | Control Unit | | :--- | :---------- | | P085015 | The button 'Gear range P' has a malfunction. There is a short circuit to positive or an open circuit. | N150 - DIRECT SELECT interface (DSI) (DSI290) | | P085011 | The button 'Gear range P' has a malfunction. There is a short circuit to ground. | N150 - DIRECT SELECT interface (DSI) (DSI290) |

Diagnosis / Trigger Conditions

The root cause of the Mercedes-Benz AMG GT P button malfunction is typically contamination or ingress of dust, or a short circuit caused by water ingress within the DSI selection lever module. These external influences can lead to the 'P' button not functioning correctly.

Important Warnings

Mercedes-Benz notes that repairs for this issue may not be covered by warranty if the cause is determined to be due to outside influence, such as contamination or water ingress.

Repair Procedure Summary

The recommended remedy involves cleaning the printed circuit board located under the plastic housing and the 'P' button of the DSI selection lever module. The procedure includes:

1. Removing the DSI selection lever module (referencing WIS document AR27.60-P-0901FRX).
2. Removing the housing of the DSI.
3. Removing the cover around the 'P' button, which is above the printed circuit board.
4. Visually inspecting the printed circuit board for liquid residues and/or contamination.
5. Visually inspecting the 'P' button for water residues and/or contamination.
6. Carefully cleaning the affected areas. The TSB specifically recommends using an electrical contact cleaner such as BW-100 or CRC QD Electronic Cleaner.
7. Reassembling the components and verifying proper function of the 'P' button.

Required Tools or Parts

For the cleaning procedure, technicians should use an appropriate electrical contact cleaner. Recommended examples include:

• BW-100 electrical contact cleaner
• CRC QD Electronic Cleaner

Owner Action

If you are experiencing a Mercedes-Benz AMG GT P button malfunction or any of the described symptoms, it is recommended to have your vehicle inspected by an authorized Mercedes-Benz service center. They can diagnose the issue, check for the relevant fault codes, and perform the necessary cleaning procedure.

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Source: NHTSA ID: 11009205