Bulb Test and Engine Running Recognition

Networking:

Indicator lamp test
The indicator lamps are tested when term. 15 is ON. All indicator and warning lamps (if installed in equipment and national variants) are tested with the exception of the
- Left turn signal indicator lamp (A1e1),
- right turn signal indicator lamp (A1e2),
- Preglow indicator lamp (A1e16)

The indicator lamps are only tested if term. 61 is set to Low (term. 61 < 9 V) (generator not yet working) and if the engine speed is less than 200 rpm.
If there are no errors the malfunction indicator lamps extinguish as soon as the engine is running.


NOTE: The DTR warning lamp (A1e59) is tested during the indicator lamp test even if the vehicle is not equipped with Distronic.


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

Term. 61e is required, for example by the injection system control module (N3) and the traction system control module (N47).
This signal can have either a "high" or "low" status.

The status is "low" when term. 61 is "low" and the engine speed is less than 200 rpm. In all other cases the signal status is "high".

The signal "term. 61e" is sent on the engine compartment CAN by the instrument cluster (A1) and is therefore made available to the other control modules of this bus system.

Networking (see figure below)

The following CAN data is required:

- Term. 61 generator check
The "term. 61" signal of the generator (G2) (generator check) is read in by the right front SAM control module (N10/7). The right front SAM control module (N10/7) then passes the message "term. 61 High " (generator functioning) or "term. 61 Low" (generator not functioning) on the passenger compartment CAN.

- Engine speed
The pulses of the crankshaft position sensor (L5) are read in by the injection system control module (N3). This control module sends the message "engine speed" (in rpm) on the engine compartment CAN.

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


NOTE: The same CAN input signals are used for the charge indicator light warning message "BATTERY/GENERATOR - GO TO GARAGE". This message appears on the multifunction display (A1p13) if "term. 61" is "low" and the engine speed is greater than 200 rpm.


The following table summarizes the associations mentioned above.







Notes on table
The CAN message "term. 61 can have the status "high" and "low". This status depends on the actual voltage at the input of the right front SAM control module (N10/7). The message is "high" if the voltage is greater then 9 V. It is "low" if the voltage falls below 4.5 Volts.