2429931 - E7051 ROBOTIZED GEARBOX - Functional description (Smart gearbox)

Functional description

The automatic transmission control unit M54 controls and governs the entire gearbox management system. The direct supply for the control unit arrives from the battery, from the line for fuse F23 of the engine compartment junction unit B1, at pin 27 of connector A of M54. The supply controlled by the ignition (15/54) reaches pin 28 from connector A of M54 via the line for fuse F16 of junction unit B1. Pins 1 and 2 of connector A of M54 are earthed. A set of sensors and potentiometers on the gearbox informs the control unit of the engaged gear: the potentiometers are supplied from pin 73 of connector B; pin 66 provides the reference earth: the gear selector potentiometer K68 provides a signal to pin 51 of connector A; the gear engagement potentiometer K69 returns a signal to pin 39 of connector A; the hydraulic unit oil pressure sensor K96 returns a signal to pin 40 of connector A. The clutch position potentiometer K95 is supplied from pin 79 of connector B, receives a reference earth from pin 59 and returns a signal to pin 52 of connector A of M54 . Pins 38 and 50 of connector A M54 are connected to the car speed sensor (gearbox input) K77 . The gear control unit H37 is connected to the control unit M54 to signal the request to engage a gear: these signals are sent to pins 67, 74, 68 of connector B of M54 ; and to pin 26 of connector A; a reference earth is received from pin 66 of connector B, whilst the supply arrives from the line controlled by the ignition (15/54) protected by fuse F16 of engine compartment junction unit B1 The operating mode selection button 'E' H34 is connected to the control unit M54 at pin 77 of connector B. This button receives a supply from the line (INT) protected by fuse F51 of the junction unit under the dashboard B2. Pin 69 of connector B of M54 receives the signal coming from the brake lights switch I30, with the supply controlled by the ignition (INT) from fuse F37 of underfacia junction unit B2. In accordance with the operating logic, the control unit controls the electrohydraulic unit located on the gearbox which effects the gear change: the electric pump N47 , which keeps the oil in the hydraulic unit under pressure, is controlled from pin 31 of connector A. The pump N47 is controlled by a specific relay J87 supplied by the line for the specific shunt fuse B43.

The control unit then controls the opening of the hydraulic unit solenoids:

• the two gear engagement solenoids L51 and L52 are controlled from pins 32 and 44 of connector A of M54 ;
• the two gear selection solenoids L53 and L54 are controlled from pins 29 and 3 of connector A of M54 ;
• the clutch control solenoid L56 is controlled from pin 43 3 of connector A of M54 .

A safety signal comes from pin 42 of connector A of M54 for the starting enablement relay pin 50 of the starter motor A20; the signal requesting starting reaches pin 76 of connector B  See E5010  STARTING AND RECHARING . The control unit M54 also manages the door open buzzer: the driver's door open signal - catch N50 - reaches pin 78 of connector B of M54 ; Signals for the gearbox failure warning light in instrument panel E50, and the instrument gear indication display, are sent via the CAN network - pins 33-45 and 7-19 of connector A of M54.The speedometer signal is downloaded via the CAN network. Pin 48 of connector A is connected to engine management control unit M10 , from which it receives an engine rpm signal. The control for the buzzer, located in the instrument panel E50, leaves from pin 80 of connector B. Self-diagnostic data can be read by connecting the unit to connector G of Body Computer M1 - pin 7: this receives signals from pin 49 of connector A of M54. (the line is shared with the engine control unit M10 via the relevant tester line.