NHTSA Service Bulletin 11031581: 2015-2026 Mercedes Benz Amg C63

Complaint CEL ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and stored in the ME (N3/10). There are no drivability concerns related to the 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 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 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 an emission extended warranty, Please perform steps outlined in the NCU for repairs. If vehicle is not covered under an emission extended warranty, 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, flush the system several 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 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 there is no new software available, the thermostat has already been replaced, and the DTC returns 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 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