Signal Missing

Signal missing

Checking the function
Check the power supply to the control module by turning the ignition to position II.
The SRS (supplemental restraint system) indicator lamp in the driver information module (DIM) must come on. The lamp must go out after approximately 7 seconds.





Does the warning lamp go out?

Yes - Checking communication

No - Checking the power supply and ground

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Checking the power supply and ground

Checking the power supply
- Check that the fuses for the power supply to the ignition switch and the power supply to the central electronic module (CEM) (fuse F3) in the engine compartment fusebox are intact
- Check that the fuses in the central electronic module (CEM) for the supplemental restraint system module (SRS) are intact.

Note! If a fuse is blown, check the circuit after the fuse before replacing the fuse. Check for a short-circuit to ground. Then replace the fuse. For further information about the circuit after the fuse, refer to the wiring diagram.

- Check the cable for the power supply between the ignition switch and the central electronic module (CEM). Check for an open-circuit. Check for a short-circuit to ground
- Check the power supply cable between the 15-supply and the supplemental restraint system module (SRS). Check for an open-circuit. Check for a short-circuit to ground.

Checking the ground terminal
- The supplemental restraint system module (SRS) is grounded when it is screwed into place in the car.
The resistance between the control module casing and the ground terminal must be 0 ohm.
The supplemental restraint system module (SRS) is powered via an internal relay in the central electronic module (CEM). Click on the VCT2000 symbol to check the status of the relay and to try to activate the relay if necessary.
Remedy as necessary

Other information
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- Connecting the breakout box Connecting the Breakout Box, Supplemental Restraint System Module (SRS)
- Signal specification Signal Specification
- Air bag supplemental restraint system Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals









Was a fault detected?

Yes - Verification

No - Signal missing

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Checking communication
- Ignition on.

Hint: The CAN communication with the control module is probably OK if the control module ID can be read off. In that case the fault is probably intermittent and will then be more difficult to trace.

Try to communicate with the supplemental restraint system module (SRS) by reading off the control module ID.
Click the symbol for VCT2000 to begin reading off.





Continue - Signal missing

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Signal missing

No Fault Found - No Fault Found

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off
- Reinstall the connectors, components etc.
Check the power supply to the control module by turning the ignition to position II.
The indicator lamp in the driver information module (DIM) must light up. The lamp must go out after approximately 7 seconds.





Does the indicator lamp go out?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information

Attempt New Test - Checking the function

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