Mercedes-Benz bulletin LI49.20-N-076565

Complaint Check engine light with fault code: P300E3B the efficiency of component 'SCR catalytic converter' is not sufficient, is present in the CDI control unit CDI (N3/28). Cause This subject is currently being analyzed for all 907s equipped with the OM642 engine. Follow the instructions related to this subject to collect information about your vehicle. After completing the checks, please open a TIPS case and attach the collected information. Remedy Please complete the following inspections and tests: 1. Perform a tailpipe wipe test and document the results along with photographs. 2. Inspect the NOx connectors, pins, crimps, and harnesses between N37/7 and N37/8 to F152f59, Z7108, W105/3, and X30/81. 3. Provide actual values/sensor plausibility test results for all pressure and temperature sensors with the engine com- pletely cooled off for at least eight hours, the key on, and the engine off. Repeat the test with the engine/exhaust at operating temperature and the engine idling. 4. Perform a pressurized smoke test of the intake, charge air system, and exhaust to verify that there are no leaks. Apply overpressure (not exceeding 26 psi) from the exhaust pipe end and seal the system at the clean airline toward the air filter housing. Manipulate all components during the smoke test. 5. Provide diesel particulate filter actual values and regeneration history. 6. Inspect the SCR temperature sensor wirings and pins for electrical and physical correctness. Determine whether this sensor reaches operating temperature while driving and document the time it takes to reach operating temperatu- re. 7. Inspect the Adblue injector nozzle/s for clogging or leaking, and provide photographs. 8. With the Adblue injector/s removed from the exhaust system, perform two to three Adblue pressure tests and check for leaks. If leaks are detected, provide photographs. 9. Collect an Adblue sample, test fluid quality, and provide notes on its condition and quantity (color, clarity, separati- on, odor, etc.), along with a photograph for review. Also, provide a photograph of the spray pattern. 10. Separate the exhaust pipe downstream of the diesel particulate filter, inspect the diesel particulate filter and SCR, and note any soot, blockage, or damage. Provide photographs. 11. Inspect the SCR catalyst interior for dried Adblue residue, and provide photographs. 12. Perform se

Owners of the 6 model years this bulletin names have filed 385 complaints with NHTSA since 2015.