GF07.61-P-2004V Diagnosis Fault Memory, ME-SFI Function
GF07.61-P-2004V Diagnosis Fault Memory, ME-SFI Function
The ME-SFI [ME] control unit checks its input and output signals for plausibility and recognizes possible faults. The detection of faults and their storage is differentiated in:
- Faults constantly present
- Loose contact fault (only on coolant temperature sensor (B11/4) and accelerator pedal sensor (B37))
The following components and systems are monitored:
- Oxygen sensors
- Catalytic converters
- CAT heater
- Secondary air injection
- Smooth running control (combustion misfire)
- Fuel system
- Control units which are linked via the data bus
Fault recognition
The following faults and error states are detected:
- Signals above or below the limit value (open circuits, short circuits, faulty sensor)
- Frequency of fault
- Illogical combination of signals
- Function chains with faults
- Fault messages of all systems transmitted via CAN data bus (control units)
- Fault states from the alternator (G2) with interface controller
Fault display via engine diagnosis indicator lamp or CHECK ENGINE
If an exhaust gas relevant error occurs or if it was already stored in the last driving cycle, the indicator lamp lights up in the instrument cluster.
In the event of a fault which could damage the catalytic converter, the engine diagnosis indicator lamp flashes. The indicator lamp goes out after 3 correct, successive driving cycles.
Fault storage
Recognized faults are stored when they arise for the first time with their environmental data in the fault memory. If the fault is not confirmed during the following driving cycle, it is deleted. Emission relevant faults are always entered, they have a high priority.
After 40 correct driving cycles an exhaust gas relevant fault and after 80 correct driving cycles a CAT damaging fault is erased from the fault memory.
Read out the fault memory
The ME-SFI [ME] control unit is connected via a serial interface (Kline) to the data link connector. The stored faults can be read out and deleted with STAR DIAGNOSIS or with a standard output device (generic scan tool) with "Ignition ON" or with the engine running via the data link connector (SAE standard ISO 9141-2).
The fault memory is not erased if the vehicle battery is disconnected.
Emergency running
If a fault is detected, substitute values are formed for the emergency running and the engine diagnosis/CHECK ENGINE indicator lamp lights up.
ME-SFI [ME] control unit run-on
After faults are erased it is necessary to wait until the processor has completed its power-down sequence after the ignition is switched off. The duration is dependent on the coolant temperature and is between 5 and 150 seconds.