2019 Mercedes-Benz AMG GLC63

Engine runs rough and activates a flashing engine light. Sounds like the engine is misfiring. On two occasions the engine stalled,(no power steering, brakes...) luckily not in a dangerous situation. No engine codes were visible to a technician when try to diagnose. Car seemed to run fine again after restart.

NHTSA ID

11682158

Incident

Aug 20, 2025

The SIM has the potential to become disabled and won’t connect to the mobile network. They have announced the problem but it has been months with no remedy even though it’s stated to be performed over the air. If I get into an accident there is a chance emergency responders will show up late if at all. This risk is there everytime I drive my vehicle

NHTSA ID

11474323

Incident

Jun 30, 2022

TL* THE CONTACT OWNS A 2019 MERCEDES-BENZ GLC63C4. THE CONTACT STATED THAT THE STEERING WHEEL SHOOK AND VIBRATED. WHEN TURNING THE VEHICLE, IT WOBBLED, MADE A LOUD KNOCKING NOISE, JERKED, AND SKIPPED WHEN THE CONTACT ATTEMPTED TO COMPLETE A TURN. THE VEHICLE WAS TAKEN TO MERCEDES-BENZ OF THE WOODLANDS (16917 INTERSTATE I45, CONROE, TX 77385, (936) 206-7500), BUT WAS NOT DIAGNOSED. THE DEALER TEST DROVE THE VEHICLE AND WAS ABLE TO RECREATE THE FAILURE. THE DEALER STATED THAT THE VEHICLE WAS PERFORMING NORMALLY. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS CONTACTED. THE APPROXIMATE FAILURE MILEAGE WAS 15.

NHTSA ID

11289368

Incident

Sep 27, 2019

Mileage

15 mi

This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below. In our continuing efforts to ensure 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 Diagnostic Module for Tank Leakage detection (DMTL) in certain Model Year (“MY”) vehicles listed below from the original New Vehicle Limited Warranty of 4 years/50,000 miles to 10 years/120,000 miles (vehicles certified as LEV II) and 15 years/150,000 miles (vehicles certified as LEV III), whichever occurs first, for the following condition: •Under certain circumstances, the DMTL may trigger erroneous Diagnostic Trouble Code (DTC) entries that may result in the illumination of the Check Engine Malfunction Indicator Lamp (‘MIL’).

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

Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class (205, 463, 253, 190 & 222 platforms) vehicles, the engine control unit software does not correspond to current production specifications. It is therefore possible that on-board diagnostics and/or exhaust gas emissions requirements may not be fulfilled.

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)

Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to cracking of the microweld between the wheel bearing inner race and the joint housing of the side shaft. Note: The collar nut must always be replaced after being loosened. See also LI33.20-P-078406 Remedy Coat contact surface of side shaft with wheel bearing with Molykote paint. To do this, proceed as follows: 1. Remove side shafts 2. Clean contact surface A (see image file in attachment "Outer joint housing before") before coating with Molykote, using "spirit" (free of dust and grease) 3. Coat contact surface A (see image file in attachment "Outer joint housing after") with Molykote and leave to dry for "one hour" in removed condition 4. Reinstall side shafts Note: Before using the antifriction coating (Molykote), stir it or shake it thoroughly for (at least 1 minute).

Complaint Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering/ maneuvering. Sound file attached for comparison. MUST match noise for proper diagnosis. NOTE: Steering functionality is not affected. Cause Contact area between wheel bearing and steering knuckle. See also: LI35.30-P-058566 (Throttle Lift-Off Noise - Rear) LI33.30-P-056665 (Throttle Lift-Off Noise - Front) LI40.10-P-059248 (Wheel cracking noise when cornering) Remedy 1. Perform Operation A and evaluate by testing vehicle. 2. If noise is still present after re-testing: • If 192/232 chassis, verify FIN is in the listed range below in "Operation B" and perform. • If not 192/232 chassis or vehicle is a 192/232 not in the listed FIN range, additional verifications of where the noise is coming from are needed. Use multiple channel NVH method to narrow down location. Verify the LI's listed above were completed or if there are other similar noises associated with the chassis (Example: 192/232 also has under panel noises and an associated LI). Operation A: 1. Clean contact surfaces of wheel bearing and steering knuckle with brake cleaner as seen in the attached pictures. NOTE: The front area of the wheel bearing and the seals must not come into contact with the cleaner, otherwise, the sealing rings will be damaged. 2. Clean threads of wheel bearing mounting. 3. Thinly coat contact surfaces of wheel bearing, steering knuckle, and axle mating face with Molykote (annular joint grease). See the attached steering knuckle and wheel hub pictures for reference. NOTE: Axle mating face greasing is also covered in LI35.30-P-058566 and LI33.30-P-056665. Operation B (Only applies to 192 and 232 in listed FIN range): Only affects vehicles up to FIN end number: • Model series 192: xxx xxx xx 002 876 • Model series 232: xxx xxx xx 022 312 1. Replace steering knuckle. 2. Wheel bearings do not need to be replaced.