This bulletin applies to 2018 Audi S4, S5 and SQ5 and 2019 RS5 vehicles.
A “switch off the engine and check coolant” message may be displayed in the instrument cluster. DTC P000000 with symptom code 33688 may be found. This indicates a possible malfunction of the mechanical coolant pump.
1. Check the cooling system for the correct coolant level in the coolant expansion tank.
a. If coolant level is correct, continue with step 2.
b. If coolant level is not correct, check the system for leaks. If leaks are found, repair as needed. If no leaks are found, top off the coolant according to ELSA.
2. Using the following table, check whether one of the software versions is already installed on the engine control unit.
Model Software P/N Version SVM code
SQ5...........80A907559C................................0008.........................01A234
S4/S5.........8W0907559H..............................0009..........................01A234
RS5............8W0907551A..............................0004..........................01A234
a. If an older software version is installed, use the respective SVM code. If the fault reoccurs after a scan, continue to step 3.
b. If one of the software versions listed above is already installed, continue with step 3.
3. Check the operation of the vacuum control of the mechanical coolant pump.
a. Check for vacuum at the output port of solenoid N649 which commands the water pump sleeve. The engine needs to be cold to generate a command signal to the N649 solenoid to switch to a vacuum. With the engine cold, start the engine briefly and monitor that a vacuum is created.
b. If there is no vacuum measured at the output port of N649, the cause of the failure could be related to the solenoid valve N649 or the vacuum hoses. Check and repair as needed.
4. If there are no malfunctions found in the vacuum system, check the operation of the water pump sleeve by applying a vacuum to the hose going to the water pump (hose connected to the output of N649). When applying vacuum to the pump, pay attention to the clicking sound of the water pump sleeve. If no clicking is heard or felt, replace the mechanical coolant pump.
