Unit, Steering Column Assembly (703)

Unit, Steering Column Assembly (703)

Main task
Primary tasks of the column integration module (CIM):
- Immobilize the car using the transponder in the key and receiver in the ignition switch module (ISM).
- Control the electronic steering column lock (SCL).
- Receive information from the ISM and transmit the key position on the bus.
- Prevent the key from being turned from LOCK to ON before the SCL has been unlocked.
- Prevent the key from being turned from ON to LOCK before the car has stopped and the selector lever moved to P or N.
- Receive radio signals from the integrated key remote control and send a message on the bus regarding which button has been pressed.
- Read the positions of the steering wheel controls and send the information on the bus.
- Transfer current to the two driver air bag detonation circuits.
- Transmit the current steering wheel angle on the bus.
- Act as a gateway between the P-bus and I-bus.
- Connect the P-bus and I-bus to the data link connector.

Type
Control module, general description

The CIM is an integrated unit which includes the traditional steering column cowls, stalk switches and steering wheel angle sensor. The CIM also contains a remote control antenna and contact roller.







The stalk switches can be replaced. If cruise control is fitted as an accessory, the appropriate stalk switch can be replaced with one with cruise control buttons. The CIM contains a microprocessor with a clock and memory. An internal bus connects the processor and memory to the I/O unit, which reads values from the A/D converter for analogue inputs, digital inputs, bus and transistor activation in the output stages.


Steering wheel angle sensor
The steering wheel angle sensor is secured with a clasp in the CIM and is directly connected to the circuit board with a 4-pin connector. The steering wheel angle sensor reads the angle of the steering wheel using a toothed wheel which meshes with the toothed inner sleeve of the contact roller.

The sensor contains 4 Hall sensors and a microprocessor. The CIM continuously sends steering wheel angle information over the bus. 0 degree corresponds to the straight ahead position. This value increases if the steering wheel is turned to the left. The sensor must be calibrated after changing the straight ahead position of the steering wheel or replacing the steering wheel. A sensor fault requires CIM replacement.

Power supply, ground and bus communication

Pin No. 1 - 23:

Wiring diagram, power supply







Wiring diagram, steering wheel contact unit, airbag







Wiring diagram, steering wheel contact unit, horn/controls