AUTOMATIC TRANSMISSION - FUNCTIONAL DESCRIPTION

1.9 JTD 16V, 2.4 JTD 20V

The automatic transmission control unit M55 controls and regulates the entire gearbox management system.

The direct power supply reaches the engine compartment junction unit B1 at pin 11 of connector A of the automatic transmission control unit M55 and at pin 1 of the gear selector contro lunit M53 via a line protected by fuse F18.

The ignition controlled supply (15/54) for the steering lock control unit M89 reaches pin 1 of connector A of M55 and pin 2 of the gear selector control unit M53 via the line protected by fuse F24 of the engine compartment junction unit B1.

Pin 9 of connector A of M55 is earthed.

The gear selector control unit M53, via pins 7-8 and 9-10 and the automatic transmission control unit M55, via pins 8-14 and 7-6, communicate via the C-CAN and interface with pins 36, 37 of connector B of the Body Computer control unit M1.

See E1050 CAN CONNECTION LINES

The Body Computer also transmits signals related to the operating status of the transmission to the display on instrument panel E050, via the B-CAN.

The reverse gear engaged signal leaves pin 13 of connector A of the automatic transmission control unit M55.

See E2022 REVERSING LIGHTS - DESCRIPTION

Pin 5 of connector A of the automatic transmission control unit M55 is connected directly to pin B4 of the steering lock control unit M89. If the gear lever is in park/neutral, the signal sent ensures that starting is allowed.

See E5010 STARTING AND RECHARING

The gear controls on the steering wheel are connected via the clock spring D47 to the gear selector control unit M53, pins 11 and 12.

The pins for connector B of the automatic transmission control unit M55 have a pin-to-pin connection at the pins for the automatic transmission solenoid valve unit 050.

The autodiagnostic system for control unit M55 is achieved by connecting to connector C of the Body Computer M1 - pin 7 -: it receives signals from pin 4 of connector A of control unit M55 via the special diagnostic line (K LINE).

See E8010 DIAGNOSTIC MULTIPLE CONNECTOR