2004 MERCEDES-BENZ SL500 Complaints

The contact owns a 2004 Mercedes-Benz SL500. The contact stated that after starting the vehicle, the message "Brakes Reached Historic Threshold" was displayed, which indicated that the brake control unit had malfunctioned. Additionally, while depressing the brake pedal, the brake pedal was spongy, causing the stopping distance to become extended. The vehicle was taken to the local dealer and was diagnosed with brake control unit failure. The contact was informed that the brake control unit needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure, but no assistance was provided. The contact stated that a 25-year warranty for the failure was previously issued by the manufacturer that was associated with the failure, but was not honored. The failure mileage was 62,800.

Question 1: The Sensotronic Brake Control (SBC) unit, which is a high-pressure "brake-by-wire" hydraulic system. Component A7/3. The component is currently installed in the vehicle and is available for inspection. Question 2: The vehicle experienced a sudden, catastrophic loss of hydraulic brake pressure while in operation. This failure required extreme physical force on the pedal and significant increase in stopping distance. The vehicle is currently in my garage with chocked wheels until I figure out what's next. A couple days ago, I had the car at a dealer and requested a review of this system and they released the car back to me stating the system status was, "OK" despite me stating to the dealer that the safety-monitoring counter was found to be at 0 on a 63,000-mile car. In all of my research, I believe this "silenced" the vehicle's ability to provide a timely service warning (Code C249F) before total hydraulic failure occurred. Question 3: Mercedes-Benz of Denver performed a diagnostic on January 21, 2026. While the dealer initially claimed the system was "OK," the total failure occurred within 72 hours of their inspection. The reason it was at Benz of Denver is because my independent mechanic confirmed the 0 actuation count which was suspicious to me. I wanted to understand the mechanical integrity of the newly purchased vehicle. Question 4: Yes, inspected by an authorized Mercedes-Benz dealership technician on January 21, 2026. Question 5: To my knowledge there were no mechanical symptoms prior to the red screen however, I cannot confirm or deny that as I had driven less than 1000 miles since I purchased the vehicle. I have no concept of how the braking "should have" felt. The only "symptom" was the technical data anomaly (the 0 actuation count) flagged by an independent shop, which I can attest the dealer refused to investigate fully. On January 24th, 2026, the RED dashboard warning appeared: "Reduced Brake Effect - Start Engine!".

The 2003-2006 R230 series seem to have a problem with the BCM (Battery Control Module) as start an electrical fire in the trunk. Very common issue and a safety hazard - this is what happened with my car. Vehicle has dual battery, starter in front, convenience battery in trunk and fuses that operate at 130 Amps - the BCM capacitors and circuit board age and at some point can no longer handle the high current and catch fire.

On many 2003 and 2004 models. Broken fuel tank baffle inside fuel tank. This is well documented and could possibly cause explosion.

ON JULY 22, 2020 THE VEHICLE (2004 MERCEDES-BENZ SL500 (R230)BEGAN MAKING A LOUD BANGING NOISE IN THE REAR WHEN STOPPING AND TURNING. I DELIVERED THE VEHICLE TO A LOCAL SHOP WHERE THE VEHICLE WAS DIAGNOSED AS HAVING A BROKEN BAFFLE IN THE FUEL TANK. THE ONLY SOLUTION IS TO REPLACE THE ENTIRE FUEL TANK. MANY OTHER OWNERS OF THIS MODEL HAVE EXPERIENCED THE SAME ISSUE AND IS CLEARLY A MANUFACTURER DEFECT; THIS CANNOT BE CAUSED BY EXCESS WEAR ON THE VEHICLE. BECAUSE THERE IS NOW A LARGE SECTION OF THE FUEL TANK FREELY SWINGING INSIDE, THERE IS A CHANCE THAT THIS COULD CAUSE A SPARK AND SUBSEQUENT EXPLOSION. I CANNOT SAFELY DRIVE THIS VEHICLE UNTIL THE FUEL TANK IS REPLACED AT A VERY LARGE COST. THIS MODEL SHOULD HAVE BEEN RECALLED WHEN THIS ISSUE WAS FIRST COMING TO LIGHT OVER 15 YEARS AGO.

TL* THE CONTACT OWNS A 2004 MERCEDES-BENZ SL500. THE CONTACT STATED ON VARIOUS OCCASIONS WHILE HIS VEHICLE WAS STATIONERY AND IN PARK, EITHER THE RIGHT SIDE OR THE LEFT SIDE OF THE VEHICLE WOULD RAISE UP THEN DESCEND TO GROUND OVER A THIRTY SECOND PERIOD INDEPENDENTLY WITHOUT WARNING. THE CONTACT ALSO STATED THAT THE HYDRAULIC FLUID LEAKED OUT OF THE ENGINE. THE VEHICLE HAD YET TO BE TAKEN TO A DEALER TO BE DIAGNOSED OR SERVICED FOR THE FAILURE. UPON INVESTIGATION, THE CONTACT LINKED HIS FAILURE TO NHTSA CAMPAIGN NUMBER :08V405000 (SUSPENSION) HOWEVER, THE VIN WAS NOT INCLUDED IN THE RECALL. THE MANUFACTURER HAD YET TO BE NOTIFIED OF THE FAILURE. THE VEHICLE HAD YET TO BE REPAIRED. THE FAILURE MILEAGE WAS APPROXIMATELY 92,000.

I EXPERIENCE A STRONG ODOR OF FUEL WHEN ENTERING MY VEHICLE AND WHEN DRIVING THE VEHICLE, ALSO WHEN DRIVING THE VEHICLE I HEART A LOUD THUMPING SOUND COMING FROM THE TRUNK AREA. SOUNDS TO ME AS THOUGH SOMETHING IS FLOATING INSIDE GAS TANK. THIS ODOR HAS SICKENED ME AND HAS SEVERELY UPSET MY STOMACH TO THE POINT THAT I'M UNABLE TO DRIVE MY VEHICLE EXCEPT FOR A SHORT DISTANCE. THE THUMPING SOUND IS CREATED WHEN VEHICLE IS MOVING OR COMING TO A STOP BUT HAPPENS CONTINUOUSLY WHILE DRIVING. *TR

THE VEHICLE HAS A BRACKET ON TOP OF THE GAS TANK THAT COMES DISENGADED AND CAUSES THIS DISTINCTIVE NOISE WHICH SOUNDS LIKE SOMETHING SWINGING AND TAPPING AGAINST THE GAS TANK AND I HAS TO HAPPEN A LOT DUE TO EVERY SERVICE I HAVE BEEN ASKED ABOUT THE PROBLEM. IT ALSO HAS TO BE SOMETHING WITH MULTIPLE VEHICLES DUE TO ONLINE MERCEDES OWNERS ARE HAVING THE SAME PROBLEM. THE SOUND IS REALLY DISTURBING AND I WOULD LIKE AN ANSWER AS TO WHAT TO DO. THANKS [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).' *PM

I SUBMITTED VIA FAX EARLIER THIS WEEK A FORMAL LETTER TO MR. EXLER THE PRESIDENT & CEO OF MBUSA AND, CC'D MR. KING OF THE NHTSA THAT INCLUDED INFORMATION ABOUT KNOWN CRITICAL SAFETY ISSUED THESE VEHICLES HAD PRIOR TO MBUSA IMPORTING THEM TO THE UNITED STATES. MBUSA FAILED TO DISCLOSE THESE KNOWN ISSUES AND, CHOSE TO IMPORTATION THESE VEHICLES VIOLATING VEHICLE IMPORTATION RULES. YESTERDAY-JANUARY 31, 2019 I RECEIVED A CALL FROM A REPRESENTATIVE OF MBUSA STATING HE WAS CALLING ON BEHALF OF MR. EXLERS OFFICE CONCERNING MY LETTER. I WILL NOT BE INTIMIDATED BY MBUSA WHILE SEEKING THE TRUTH ON WHY MBUSA ALLOWED THESE VEHICLES TO ENTER THE USA KNOWING THESE CRITICAL SAFETY ISSUES EXISTED WHILE MISLEADING CONSUMERS AND, THE NHTSA. ON JANUARY 21, 2019 MY VEHICLE HAD WHAT IS DESCRIBED BY MBUSA AS A CATASTROPHIC FAILURE WHEN THE ENTIRE BRAKE SYSTEM FAILED. THIS FAILURE COULD HAVE KILLED ME - AND, OTHER MOTORIST. MBUSA HAS REPLACED THE SBC UNIT AT LEAST 6 TIMES AND, STILL THE ISSUE AND, OTHER PERSIST. THE VEHICLE HAS BEEN DRIVEN ON AVERAGE 4,000 MILES ANNUALLY. HOW MANY FAILURES MUST HAPPEN BEFORE MBUSA IS FULLY INVESTIGATED? THEY REFUSED TO PROVIDE ME ANY INFORMATION ON THE VEHICLES EXCEPT THE 4 YEAR WARRANTY PERIOD. ONCE I COMPLETE MY RESEARCH ON THESE VEHICLES I WILL SUBMIT MY FINDINGS TO THE NHTSA & MS. KING

TL* THE CONTACT OWNS A 2004 MERCEDES-BENZ SL500. WHEN THE VEHICLE WAS STARTED, THE CONTACT HEARD AN ABNORMAL KNOCKING SOUND UNDERNEATH THE VEHICLE NEAR THE FUEL TANK. ADDITIONALLY, THERE WAS A CONSTANT FUEL ODOR INSIDE THE VEHICLE. THE VEHICLE WAS TAKEN TO MERCEDES-BENZ OF VIRGINIA BEACH (LOCATED AT 4949 VIRGINIA BEACH BLVD, VIRGINIA BEACH, VA 23462, (757) 499-3771) WHERE IT WAS DIAGNOSED THAT ONE OF THE BAFFLES IN THE FUEL TANK FRACTURED, SEPARATED, AND NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED. THE APPROXIMATE FAILURE MILEAGE WAS 144,000. THE VIN WAS NOT AVAILABLE.