Crash Signal, Checking

Crash Signal, Checking

The Engine Control Module (ECM) receives the crash signal ("Crash shut-down activated") from the airbag control module.

If the airbag control module sends the crash signal to the ECM (if an accident occurred or if a output Diagnostic Test Mode (DTM) was carried out), the ECM shuts off the fuel pump, that means the engine stalls, however, afterwards the engine can be started again (e.g. when removing the vehicle from the accident area)

The ECM cannot switch off the fuel pump during an accident if the malfunction "Crash Signal from Airbag Control Unit/Range Performance" from the airbag control module is sent to ECM. The engine control module cannot recognize the crash signal from the airbag control module; e.g.: if the wiring between the ECM and the airbag control module is faulty.

- Connect VAG1598/31 test box to wiring harness for engine control module. Do not connect to the engine control module itself. Refer to "Connecting VAG1598/31 Test Box" under "Powertrain Management/Computers and Control Systems/Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG1598/31 Test Box" Testing and Inspection

Test the following wiring connections for open circuit and/or short to B+ or Ground (GND) and open circuit.

VAG1598/31 box, test Airbag control module,
socket contact
67

Resistance in wiring: max. 1.5 Ohms

Eliminate open circuit or short circuit.

If no malfunctions are found in wiring: Check DTC memory of airbag control module.