Description of On-Board Diagnostics

Troubleshooting:

General:

Note This system does not feature diagnostic capabilities, using the BMW DIS or MoDic.

This troubleshooting program is used only on vehicles equipped with ASC (Automatic Stability Control) and a 55-pin connector at the ABS/ASC control unit. The ABS warning lamp in the instrument cluster and the lamp in the passive button for the ASC light after switching on the ignition. The ABS warning lamp must go out once again after the engine has started. Only the ASC passive lamp (PALA) lights until the ASC system is intentionally deactivated with the passive button (PATA). The PALA lamp flushes during an ASC function and "ASC" appears in the display unit of the instrument cluster.

The causes of fault displays in the instrument cluster or the warning/passive lamps not lighting, not switching off or lighting during a trip (also occasionally) can be determined with the aid of the troubleshooting procedure. The defect sources are located with the defect code overview and reference is made to individual tests.

For each defect symptom, for which "ASC defect" appears in the display unit of the instrument cluster, initially the flash code should be read out at the passive lamp, see flash code.

Generally, the electronic circuitry (control units) is extremely reliable therefore this troubleshooting program is mainly designed for the periphery voltage supply, signals, function of the relays and valves. Before replacing a control unit when a defect code is indicated, it is therefore always advisable to initially carry out the relevant periphery tests as described in the following. The majority of these tests can be carried out with a multimeter (e.g. Service Tester multimeter program). The universal adapter with a 55-pin connector is used for connection to the wire harness connector. If only the pin number is specified in the test instructions, this always refers to the 55-pin wire harness connector X7 or the pin number at the universal adapter.

Important!

The ground terminal point of the battery (under right rear seat) must be disconnected when measuring the resistance on current-carrying wires (Attention! The memories of all systems will be cleared!). Always switch off the ignition first before disconnecting and connecting the 55-pin connector.

Caution!

High voltage pulses are applied at Pin 38 (control unit connector/universal adapter) when the engine is running.