# Service bulletin LI88.20\-P\-071570

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.

- Type: Service bulletin
- NHTSA id: 10237258
- Published by NHTSA: 2023\-06\-05
- Manufacturer's number: LI88.20\-P\-071570
- Manufacturer's date: 2023\-05\-09
- NHTSA component: STRUCTURE; EXTERIOR LIGHTING

## NHTSA's summary

Complaint Bulging of front bumper above headlamps \(see attachment\). Function of headlights not blocked or impaired. Cause Bonding between bracket and bumper may be separating.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2023/MC-10237258-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2023/MC-10237258-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Body and frame, Lighting

## Vehicles listed

- 2020 to 2023 MERCEDES\-BENZ AMG GT43
- 2019 to 2023 MERCEDES\-BENZ AMG GT53
- 2019 to 2023 MERCEDES\-BENZ AMG GT63
- 2022 to 2023 MERCEDES\-BENZ AMG GT63 S
- 2019 to 2021 MERCEDES\-BENZ AMG GT63S

## Recalls for the same vehicles and component

- [22V938000](/recalls/nhtsa/22V938000.md), 2022-12-16: LATCHES/LOCKS/LINKAGES; STRUCTURE:CRITICAL FASTENERS
- [2020613](/recalls/tc/2020613.md), 2020-12-12: Lights And Instruments
- [20V775000](/recalls/nhtsa/20V775000.md), 2020-12-11: EXTERIOR LIGHTING:HEADLIGHTS

## Other bulletins for the same vehicles and component

- [LI82.62\-P\-078631](/bulletins/11038217.md), 2026-10-06, Service bulletin: STRUCTURE:BODY. Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and if necessary, create a TIPS case with an informative video as an attachment. Note: Please refer to this document in the warranty claim and, once diagnosis is completed, select the damage code depending on the component part that is causing the issue. • If the noise stops when the door trim is removed, please proceed in accordance with LI72.10‑P‑067691. Information: In this case, do not use a damage code for the speakers in the warranty claim\!
- [LI82.62\-P\-078631](/bulletins/11036101.md), 2026-08-11, Service bulletin: STRUCTURE:BODY. Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and if necessary, create a TIPS case with an informative video as an attachment. Information: Please refer to this document in the warranty claim and, after completing diagnosis, select the damage code corresponding to the component part that caused the problem. • If the noise stops when the door trim is removed, please proceed in accordance with LI72.10\-P\-067691. Information: In this case, do not use a damage code for the speakers in the warranty claim\!
- [LI40.10\-P\-059248](/bulletins/11035214.md), 2026-07-24, Service bulletin: STRUCTURE:BODY; WHEELS. Complaint Crackling and cracking noise from the outer wheel on the front axle when cornering Cause The noise is generated by a micromovement on the contact surface between the rim and the brake disk \(wheel bolt group\) and may be intensified by potential soiling. The more lightweight rim \(AMG forged rim\) transmits the noise louder; in the case of cast rims, the noise is generally not perceptible. This is not a technical defect, but rather a complaint concerning comfort. Safe operation of the vehicle is ensured at all times. Remedy Important note: The operations described below do not represent a permanent remedy in every case. The noise may reoccur again after an indefinite period of time; sanding the rims with abrasive media multiple times is not permissible. Only cleaning using the Hazet tool 4960\-160 \(recommendation\) can be performed without any concerns each time the wheel is changed or if the complaint reoccurs. Replacing the parts \(rim, wheel bolts, wheel bearings, wheel hub, brake disk\) is not expedient in the event of this complaint. \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\- Clean the components of the wheel bolt connection according to the WIS instructions Sand down the rim and brake disk bowl by performing the following steps: • Manually sand rim \(old design only\) in area of water drain bores \(Figure 1; item A\), approx. 1.5 cm left and right of water drain bore \(Figure 2\) Note: Use abrasive paper with grit size 80. The grooving in this area should no longer be visible \(sand down approx. 0.1\-0.2mm\) • Also sand brake disk bowl using emery cloth or abrasive paper with a grain size of 120 • For vehicles equipped with the AMG ceramic brake system \(B07\), abrasive paper may not be used for cleaning on the brake disk side Note: Do not use any cleaning agent when cleaning on the rim side. Cleaning using abrasive paper with a grain size of 80 will suffice. Do not apply any grease, lubricant or paste after cleaning The brake disk bowl should be "bare metal" in the area of the imprints made by the hole \(Figure 3\)
- [PSL\-NCU Return Parts 6/26](/bulletins/11034099.md), 2026-06-26, Other: STRUCTURE:BODY. Dear Mercedes\-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, July 16th, 2026. After July 16th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.
- [PSL\-NCU Return Parts 5/22](/bulletins/11033050.md), 2026-06-01, Other: POWER TRAIN; STRUCTURE:BODY. Dear Mercedes\-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, June 11, 2026. After June 11th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.
- [LI82.10\-P\-078301](/bulletins/11031580.md), 2026-04-27, Service bulletin: EXTERIOR LIGHTING. Complaint Headlamp, front fog lamp leaky or fogged. Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Remedy Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps: 1. Drive vehicle into workshop \(temperature higher than \+18 °C/\+64.4 °F\) and connect the exhaust extraction. Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Clearing of fogged/condensed LED headlamps and LED rear lamps on electric vehicles: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). 2. Connect battery backup via a charger. 3. Open the front\-end flap and ensure sufficient ventilation. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Clearing fogged/condensed halogen/xenon headlamps: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine. 3. Open the hood. 4. Switch off the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Note: If there is no visible reduction in condensation, check the headlamp for malfunctions. \(see Remedy 2\) It is not physically possible to defog the headlamps completely. Fogging does not impair the operation or the service life of the headlamp. Note: Only implement Remedy 1 for model series 463 \(from model year 2018\) and model series 465. Remedy 2 A defective headlamp can be identified as follows: 1. Check the headlamp for external damage and that the cover caps and the diaphragm are correctly seated. 2. Check the electrical connectors of the plugs and pins. 3. Check for leak tightness according to LI82.10\-P\-078307. The test can only be conducted on headlamps. 4. If the headlamp or the rear lamp has any external damage, replace the component part in accordance with the WIS instructions. Note: External damage to the headlamp/rear lamp or faulty seating of the cover caps does not present a warranty or goodwill case. Note: With headlamps, it is possible to install desiccant packs if the problem occurs repeatedly. • Open ventilation system LI82.10\-P\-078302 • Closed ventilation system LI82.10\-P\-078304
- [LI82.10\-P\-078301](/bulletins/11029959.md), 2026-03-11, Service bulletin: EXTERIOR LIGHTING. Complaint Headlamp, front fog lamp leaky or fogged Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Remedy Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps: 1. Drive vehicle into workshop \(temperature higher than \+18 °C/\+64.4 °F\) and connect the exhaust extraction. Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Clearing of fogged/condensed LED headlamps and LED rear lamps on electric vehicles: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). 2. Connect battery backup via a charger. 3. Open the front\-end flap and ensure sufficient ventilation. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Clearing fogged/condensed halogen/xenon headlamps: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine. 3. Open the hood. 4. Switch off the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Note: If there is no visible reduction in condensation, check the headlamp for malfunctions. \(see Remedy 2\) It is not physically possible to defog the headlamps completely. Fogging does not impair the operation or the service life of the headlamp. Note: Only implement Remedy 1 for model series 463 \(from model year 2018\) and model series 465. Remedy 2 A defective headlamp can be identified as follows: 1. Check the headlamp for external damage and that the cover caps and the diaphragm are correctly seated. 2. Check the electrical connectors of the plugs and pins. 3. Check for leak tightness according to LI82.10\-P\-078307. The test can only be conducted on headlamps. 4. If the headlamp or the rear lamp has any external damage, replace the component part in accordance with the WIS instructions. Note: External damage to the headlamp/rear lamp or faulty seating of the cover caps does not present a warranty or goodwill case. Note: With headlamps, it is possible to install desiccant packs if the problem occurs repeatedly. • Open ventilation system LI82.10\-P\-078302 • Closed ventilation system LI82.10\-P\-078304
- [LI82.10\-P\-078301](/bulletins/11029025.md), 2026-02-25, Service bulletin: EXTERIOR LIGHTING. Complaint Headlamp, front fog lamp leaky or fogged Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Remedy Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps: 1. Drive vehicle into workshop \(temperature higher than \+18 °C/\+64.4 °F\) and connect the exhaust extraction. Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Clearing of fogged/condensed LED headlamps and LED rear lamps on electric vehicles: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). 2. Connect battery backup via a charger. 3. Open the front\-end flap and ensure sufficient ventilation. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Clearing fogged/condensed halogen/xenon headlamps: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine. 3. Open the hood. 4. Switch off the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Note: If there is no visible reduction in condensation, check the headlamp for malfunctions. \(see Remedy 2\) It is not physically possible to defog the headlamps completely. Fogging does not impair the operation or the service life of the headlamp. Remedy 2 A defective headlamp can be identified as follows: 1. Check the headlamp for external damage and that the cover caps and the diaphragm are correctly seated. 2. Check the electrical connectors of the plugs and pins. 3. Check for leak tightness according to LI82.10\-P\-078307. The test can only be conducted on headlamps. 4. If the headlamp or the rear lamp has any external damage, replace the component part in accordance with the WIS instructions. Note: External damage to the headlamp/rear lamp or faulty seating of the cover caps does not present a warranty or goodwill case. Note: With headlamps, it is possible to install desiccant packs if the problem occurs repeatedly. • Open ventilation system LI82.10\-P\-078302 • Closed ventilation system LI82.10\-P\-078304
- [LI82.10\-P\-078896](/bulletins/11017500.md), 2025-05-02, Service bulletin: EXTERIOR LIGHTING. Complaint Headlamps leaking or fogged Cause The fogging of the headlamp is a natural phenomenon which can occur under certain climatic conditions. In contrast to a leaky headlamp, physical fogging does not result in a technical impairment of the headlamp. A leak test must be performed to determine if physical fogging exists or if the headlamp is leaky. Remedy Check for external damage: You can identify a damaged headlamp in the following way: For headlamps with a closed system 1. Check the headlamps for any external damage and check also for correct seating of the Gore\-diaphragm/correct latching of the cover caps. 2. If the headlamp exhibits any external damage, replace the headlamp. For headlamps with an open system 1. Check the headlamps for any external damage and seal off the vent, then make sure the cover caps are latched correctly into place. 2. If the headlamp exhibits any external damage, replace the headlamp. Note: External damage to the headlamp does not present a warranty or goodwill case. 1. Clear fogged/condensed LED headlamps and LED rear lamps: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood or trunk. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). 7. If the condensation has disappeared, nothing else has to be done. Note: If defrosting has been performed, you can skip the first step. 2. Leak test of headlamp with overpressure: • Connect test adapter to pressure tester. \(Figure 1\) • Check test adapter for leak tightness. To do so, connect plug and coupling \(picture 2\) and apply a maximum overpressure of 30 mbar. The pressure must remain constant. If the pressure does not remain constant, use a new adapter. • All vents have to be sealed with sealing compound and the existing diaphragm with the stamp \(picture 3 \[3\]\). \(Picture 4\) Make allowance for the different headlamp variants here \(there are different outlet openings\). • Check if the headlamp needs to be removed to gain access to the diagnostic socket on the headlamp housing. • Plug the adapter onto the diagnostic socket on the headlamp housing. \(Picture 5\). • Apply a maximum of 30 mbar overpressure to the headlamp housing. Note: If the maximum overpressure of 50 mbar is exceeded the headlamp seal will be damaged \(picture 6\). • If a pressure drop of less than 10 mbar is measured within 30 seconds, the headlamp is tight and there is natural physical condensation. • If a higher pressure drop than 10 mbar is measured within 30 seconds, the headlamp is leaky. Note: The leaky position can be localized with the aid of soap suds. If the pressure test is not passed, the headlamp is leaky. If the cause cannot be rectified, the headlamp must be replaced. Note: If the headlamp is replaced, no dry packs may be installed on the new replacement headlamp. AR82.10\-P\-5455WT was created for the pressure test. This AR can be used as a reference manual for all closed headlamps. In the event of an open headlamp system, the vent ducts must be sealed before the pressure test.
- [LI82.10\-P\-078301](/bulletins/11017496.md), 2025-05-02, Service bulletin: EXTERIOR LIGHTING. Complaint Headlamp, front fog lamp leaky or fogged Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. Remedy NOTE: If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps and LED rear lamps: 1. Drive vehicle into workshop \(temperature higher than \+18 °C/\+64.4 °F\) and connect the exhaust extraction. Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood or trunk. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Clearing fogged/condensed halogen/xenon headlamps: 1. Drive the vehicle into the workshop \(temperature higher than \+18 °C/\+64.4°F\). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine. 3. Open the hood. 4. Switch off the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable \(thawing progress\). Note: If there is no visible reduction in the formation of condensation, check the headlamp for damage. \(See Remedy 2\) It is not physically possible to defog the headlamps completely. Fogging does not impair the operation or the service life of the headlamp. Remedy 2 A damaged headlamp can be identified as follows: 1. Check the headlamp for external damage and that the cover caps and the diaphragm are correctly seated. 2. Check the electrical connectors of the plugs and pins. 3. Check for leak tightness in accordance with LI82.10\-P\-078896 The test can only be conducted on headlamps. 4. If the headlamp or the rear lamp has any external damage, replace the component part in accordance with the WIS instructions.

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