3239403 - E4021 SPEEDOMETER - Functional description

Functional description

The supply to the speedometer module E10 reaches pin 9 of connector A directly from the battery (maxifuse J/B1of B99 ) via fuse F10 of the junction unit B1 ; the supply controlled by the ignition (INT) reaches pin 10 of connector A from the line protected by fuse F4 of the additional fuse box B98B . Pin 1 of connector A is earthed. The ABS control unit M50 sends the speedometer signal to pin 11 of connector A of E10 . The speedometer signal is sent again from pin 15 of connector A to the climate control system control unit M70 andfrom pin 16 of connector A towards the engine management control unit M10 .

Functional description

The ABS control unit M50 also sends the 'ABS failure' signal to pin 6 of connector A of E10 which lights up the warning light. The signals for the handbrake switch I40 and brake fluid level sensor K25 both reach pin 7 of connector A of E10 .

The low brake fluid level and handbrake warning light also comes on upon a command from the ABS control unit., together with the ABS failure warning light, to indicate a fault in the EBD braking system.

If it comes on by itself, the brake fluid level is low or the handbrake is on. The earth signals which provide information on the state of wear of the brake pads, coming from sensor K20, reach pin 11 of connector B of E10 . The zeroing signal for the trip meter reaches pin 12 of connector B from H10 ; an earth signal from E10 reaches pin 6 of connector B; according to the logic processed by the internal electronic device, the speedometer receives the side lights on signal at pin 5 of connector B and sends the lighting signal to the other instruments: to the centre instrument E20 from pin 12 of connector A; and to the rev counter E15 from pin 4 of connector B  See E2530  INSTRUMENT LIGHTING . A signal reaches pin 3 of connector B from the left front door switch N50 which signals that the door is open. Pin 2 of connectorA of E10 receives the earth signal from the switch l45 , located on the driver's seat anchorage, which indicates that the belt is fastened: this signal is sent again from pin 3 of connector A to the check module E30 .  See E4022  CENTRE INSTRUMENT (CHECK) Pin 8 of connector B of E10 receives the engine rpm signal from the rev counter E15 . A serial line connects module E10 - from pin 8 of connector A - to the Infocenter module E63 . Pins 2 and 7 of connector B receive (positive and negative) signals coming from the fuel gauge N40 located in the fuel pump assembly: these signals are then sent again - from pins 9 and 10 of connector B - to the centre instrument E20 See E4023  DASHBOARD CENTRE AUXILIARY EQUIPMENT() .

Functional description

The information concerning the engine oil level arrives from sensor K32 at pins 5 and 13 of connector A of E10 and is sent again from pin 8 to connector A of module E63 which displays it.

Functional description

For all the other warning lights, refer to the diagrams for the components to which they refer.