Indicator lamp test and engine running detection, function - GF54.30-P-2014TM

MODEL 211.0/2 as of 1.6.06 except CODE (494) USA version except CODE (498) Japan version

MODEL 211.0/2 as of 1.7.06 with CODE (494) USA version with CODE (498) Japan version

Shown with engine 272

Fig 1: Indicator Lamp Test And Engine Running Detection Function Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Indicator lamp test

An indicator lamp test is performed via the instrument cluster at "circuit 15 ON". All available indicator and warning lamps are actuated, except:

left turn signal indicator lamp (A1e1)
right turn signal indicator lamp (A1e2)
High beam indicator lamp (A1e3)
Seat belt reminder light (A1e9)
Preglow indicator lamp (A1e16) (diesel)

The indicator lamp test occurs only for as long as the Controller Area Network (data bus/CAN bus) (CAN) message "circuit 61 < 9 V" is present at the instrument cluster.

Engine running recognition "circuit 61e"

The instrument cluster links the CAN messages "Circuit 61" and "Engine speed" to a CAN message at "Circuit 61e" (engine operation detection). This CAN message can have either a "HIGH" or "LOW" status.

It is "LOW" when the status is "Circuit 61 < 9 V" and the engine speed is below 200 RPM.

If the engine speed is > 200 RPM, the CAN message "HIGH" is sent. The signal "Circuit 61e" is placed by the instrument cluster on the Controller Area Network bus class C (engine compartment) (CAN-C) and as a result is available to the control units which need this CAN message.

Networking

The signal for circuit 61, from the alternator (alternator check), is read in by the driver-side SAM control unit with fuse and relay module. The driver-side SAM control unit with fuse and relay module then places the message "Circuit 61 HIGH" (alternator operating) or "Circuit 61 LOW" (alternator not operating) on the Controller Area Network bus class B (interior) (CAN-B).

Engine speed

The pulses from the crankshaft Hall sensor are read in by the ME-SFI [ME] control unit or by the CDI control unit (N3/9). The respective engine control unit places the message "engine speed" on the CAN C. The instrument cluster receives this message, evaluates it and issues the value via the tachometer (A1p5).

The same CAN messages are used for the charge circuit warning "BATTERY/ALTERNATOR SERVICE REQUIRED." This message appears in the multifunction display (A1p13) if "Tml. 61 LOW" exists and the engine speed is greater than 200 RPM.

Instrument cluster, component description

GF54.30-P-6000TM