System overview

Применимость

To detect wheelspin, the DSA control module needs information on the speeds of all four wheels. This information comes from the ABS control module (2) and is transmitted continuously. The DSA control module (1) can detect whether one or both driven wheels are losing grip with the road surface.If it detects wheelspin, the DSA control module (1) sends a signal to the engine control module (ECM) (3) to reduce torque. The engine control module (ECM) does this by disabling one or more injectors (4) in different steps.The engine control module (ECM) communicates with the DSA control module via three communication lines.

• The first communication line is used for the transmission of both speed (frequency of pulses/one pulse per pass of TDC) and engine loading. The engine loading is given by the pulse width. Variations of pulse width also give extra information such as starting, idling, MT/AT (manual transmission/automatic transmission) etc.
• The second communication line transmits accelerator pedal position. Every 20 ms there is a pulse the width of which is proportional to the given value.
• A third communication line is used for the transmission of the torque reduction of the DSA control module to the engine control module. Here the pulse frequency is 5 ms and again the pulse width is the information carrier.

The DSA system is switched on every time the engine is started.The system can be disengaged using the DSA switch (8) on the centre console. The DSA system can be reactivated by pressing the DSA switch again or it will reactivate the next time the ignition is switched on again.The DSA warning lamp is on the instrument panel (5). This lamp indicates system status.

• The DSA warning lamp lights up 2 seconds after the engine has started. During this time, the DSA on-board diagnostic system (OBD) carries out self-diagnostics to check that both the ABS and engine control modules are OK.
• If the DSA warning lamp stays on, the system is not operational. There is a system fault, or the system has been switched off manually.
• If the DSA warning lamp flashes while driving, the system is active and actively reducing engine torque.

Diagnostic codes from the DSA system can be read out using VIDA, which is connected via VCT 2000 to the data link connector (6).