NHTSA Service Bulletin 11029087: 2017-2026 Mercedes-benz Amg Cls53

Complaint This LI does Not apply to 223 or 206 which use a different generation of 48V systems. Please follow the relevant guided tests for the 223 and 206. For 223 with fault code B1FCB97 follow LI54.10-P-076026. Various causes are possible. The faults listed in the various causes do not all have to be present at all times. Some of these complaints may overlap. Rely on the faults listed in the Cause section for identifying the correct Remedy. 1. No start 2. Yellow or red instrument cluster message for 48 V on-board electrical system battery (G1/3) 3. Limp home mode, overheating, A/C not blowing cold, or loss of acceleration 4. Check Engine Light Cause Cause 1: Software causes Intermittent No Starts with fault B183387 in DC/DC converter N83/1 Cause 2: Software causes Permanent No Start with fault B183349. May also have fault B183371. Cause 3: Hardware short circuit in 48V system causes fault B183319 in 48V battery. May also have fault B183371. Cause 4: Internal 48V battery Peltier cooling element failure causes fault B183397 Cause 5: This will Always have fault code B183371 but different from cause 2 and 3 -- it will Not have B183349, B183319, or any other faults in the 48V battery. This will only have fault B183371 in 48V battery. Cause 5 is from the 48V battery detecting an abnormality which then causes the 48V battery to disconnect itself. The disconnected 48V battery then causes subsequent symptoms: Limp Home Mode, overheating, A/C not blowing cold, or loss of acceleration Cause 6: Check Engine Light with fault P0606F1 in the N127 PTCU Cause 7: Check Engine Light with possible no start and fault P057FF1 Remedy Note: each of these remedies correspond to a specific cause. Make sure to match correct Cause with Remedy. Remedy 1: 1. Check the 12V power supply and LIN connection 2. Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons 3. Road test and release vehicle if no further symptoms Remedy 2: 1. Charge the 12V battery (Charging current <5A) 2. Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons 3. Road test and release vehicle if no further symptoms If the faults return or cannot be cleared: 1. XENTRY MUST be connected with VCI cable to correctly complete this remedy. 2. Complete guided test for B183349. 3. If guided test completes, vehicle starts, and drive cycles show no further symptoms, release vehicle. 4. If after guided test completes, XENTRY states to replace 48V battery: replace only 48V battery. If vehicle is a MY21 w/M256 engine, update SW in 48V battery 5. If this is a repeat visit for fault B183349 and guided test has already been completed, open a TIPS case. 6. If guided test does not complete OR symptoms are still present open a TIPS case. 7. If communication cannot be established with 48V battery perform physical layer check at 12V wiring to DCDC. If no abnormalities found, replace the 48V battery. 8. If guided test completes but a new fault code is present (such as B183319, B183371, etc.) follow the relevant Cause/Remedy for that fault in this LI. Remedy for 3: (If this occurred after Campaign 2025050001, this Li does not apply and LI54.10-P-079772 should be followed) 1. If fault is not Current (only Stored): 1. Update software in G1/3 (48V battery) using newest XENTRY software and Add-ons 2. Road test and release vehicle if no further symptoms If the faults return or this is a second visit after the SW update: 1. Complete the guided test for B183319 2. Perform XENTRY actuations for all 48V components. 3. Create a TIPS case with ALL Preliminary measures required as noted below for Remedy 5 4. Upload to TIPS case ISA performance data from the N129. 5. ISA performance data location in XD: 6. N129 control unit under Special Procedures 7. "Procedures for support queries to market support" 8. "Collation of diagnosis performance data" 9. "engine at idle" See attachment for further instructions.