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Home >> Mercedes Benz >> 2005 >> S55 >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Fuses/Relays, Network, Sensors & Switches - Basic Knowledge -- 215 & 220 Chassis >> Basic Knowledge >> Function to test malfunction indication lights and engine running detection - GF54.30-P-2014S

Function to test malfunction indication lights and engine running detection - GF54.30-P-2014S

Model 215, 220 

Networking of components 

Fig 1: Networking Of Components For Malfunction Indication Lights And Engine Running Detection
G04849651

Lamp test: 

A lamp test is performed when term. 15 is ON. During this test, all of the indicator and warning lamps present on a particular vehicle (as defined by individual options as well as national version) are checked, with the exception of:

are actuated.

The lamp test 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 will go out as soon as the engine starts to run.

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

Engine running detection, terminal 61e, valid up to 31.8.02: 

The instrument cluster (A1) links the CAN messages "Terminal 61" and "engine speed" to a CAN message at "Terminal 61e" (engine running detection).

"Term. 61e" is, for example, required by the motor electronics control unit (N3/10) or by the CDI control unit (N3/9) and traction systems control unit (N47).

This signal can have either a "high" or "low" status.

It 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 "Term. 61e" signal is transferred by the instrument cluster (A1) to the engine compartment CAN where it is then available to the control units.

Networking (see diagram above).

Engine running detection, terminal 61e, valid up as of 01.9.02: 

The instrument cluster (A1) links the CAN messages "Terminal 61" and "engine speed" to a CAN message at "Terminal 61e" (engine running detection).

"Term. 61e" is, for example, required by the motor electronics control unit (N3/10) or by the CDI control unit (N3/9) and traction systems control unit (N47). This signal can have either a "high" or "low" status.

It 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 "Term. 61e" signal is transferred by the instrument cluster (A1) to the engine compartment CAN where it is then available to the control units.

Networking (see diagram above).

The following CAN data is required:

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

IMPORTANT The same CAN message is used for the charge indicator warning message "BATTERY/ALTERNATOR VISIT WORKSHOP". This message appears on the multifunction display (A1p13) if "Term. 61" is "low" and the engine speed is greater than 200 rpm.

The following chart recapitulates the interrelationships portrayed in the above section.

Notice regarding the chart 

The CAN message "Terminal 61" can assume the states "High" and "Low". This status depends on the actual voltage at the input of the right front SAM control unit (N10/7). It becomes "High" when this voltage exceeds 9 V. It becomes "low" when the voltage drops back below 4.5 V.

Terminal 61 Engine speed Terminal 61e Instrument cluster (A1)
low (< 4.5 V) too low low Indicator lamp test
low (< 4.5 V) o.k. high "BATTERY/ALTERNATOR VISIT WORKSHOP"
high (> 9 V) too low high -
high (> 9 V) o.k. high -
low (< 4.5 V) Signal error low Indicator lamp test
high (> 9 V) Signal error high -
  Instrument cluster (IC), location / task   GF54.30-P-3039S