Indicator Lamp Test and Engine Running Recognition, Function

Indicator Lamp Test And Engine Running Recognition, Function







Indicator lamp test
An indicator lamp test is performed every time terminal 15 is switched ON. All indicator and warning lamps (if installed in the equipment and national versions) are actuated with the exception of the
- Left turn signal indicator lamp (A1e1)
- Right turn signal indicator lamp (A1e2)
- High beam indicator lamp (A1e3)
- Seat belt warning lamp (A1 e9)

The indicator lamp check continues only for as long as Terminal 61 is at low level (Terminal 61 < 9V) (alternator not yet in operation) and the engine speed remains below 200 rpm. If no malfunctions are present the lamps go out as soon as the engine starts to run.

NOTE: The DTR warning lamp and indicator lamp (A1e59) is also actuated during the indicator lamp check, even if the vehicle is not equipped with Distronic.

Engine running recognition, terminal 61e
The instrument cluster (A1) links the CAN messages "Terminal 61" and "Engine speed" to the CAN message "Terminal 61e engine running recognition".

The terminal 61e signal is required e.g. by the ME-SFI control module (N3/10) and the ESP, SPS and BAS control module (N47-5).
This signal can have either a "High" or "Low" status.
It is "Low" when terminal 61 is "Low" and the engine speed is less than 200 rpm. In all other cases the signal status is "High".

The terminal 61e signal is transmitted on the engine compartment CAN by the instrument cluster (A1), and is thus available to those control modules of this bus system which require this CAN message.

Networking (see figure)
The following CAN messages are required:
- Terminal 61 alternator check
The "Terminal 61" signal from the alternator (G2) (alternator check) is registered by the passenger-side SAM control module (N10/11). The passenger-side SAM control module (N10/11) then relays the message "Terminal 61 High" (alternator operating) or "Terminal 61 Low" (alternator not operating) onto the interior compartment CAN.
- Engine speed
The pulses from the transmitter for the crankshaft position sensor (L5) are registered by the ME-SFI control module (N3/10). This control module relays the engine speed message (in rpm) onto the engine compartment CAN.

The instrument cluster (A1) receives these messages and evaluates them as described above.

NOTE: The same CAN messages are used for the charge indicator warning "BATTERY/ALTERNATOR VISIT WORKSHOP." This message appears in the right multifunction display (A1p15) when "Terminal 61" is "Low" and the engine speed is higher than 200 rpm.

The table summarizes the relationships.







Notes on table
The CAN message "Terminal 61" can assume the states "High" and "Low". This state varies according to the actual voltage at the input of the passenger-side SAM control module (N10/11). It becomes "High" when this voltage exceeds 9 V. It becomes "Low" when the voltage drops back below 4.5 V.