Restraints and Safety Systems: Testing and Inspection

Complaint: Noises from airbag unit on steering wheel.

Cause:
- Failure to observe installation sequence with the result that airbag unit is not properly adjusted and centered.
Remedy:
- Loosen Torx screws and align airbag unit on the steering wheel so that it is positioned evenly. Screw in both Torx screws a few turns, then tighten left-hand screw to the specified torque (6 Nm). Next, pull the airbag unit on the right slightly away from the steering wheel and tighten right-hand screw likewise to the specified torque (6 Nm).

Complaint: SRS malfunction indicator lamp flickers, comes on occasionally or comes on and remains on.

Cause:
- Film of grease on slip ring of steering wheel.
Remedy:
- Clean slip ring thoroughly (also behind tracks). Wash off with cleaning petroleum, blow out and rub dry with lint-free cloth. Install new slip ring if necessary.

Cause:
- Open circuit in connection cable at outer slip ring.
Remedy:
- Replace slip ring.

Cause:
- "Cold solder point" on wiring harness.
Test:
- Test wiring harness with socket box and multimeter. Jiggle or move connectors of wiring harness when performing test. Test readings must remain constant.
Remedy:
- Solder cable correctly.

Cause:
- Sleeves at connectors widened with the result that pre-tension to mating piece is insufficient.
Test:
- Jiggle or move 10-pin connector of test coupling (X11/13) during test cycle -4 to 20 seconds- conducted by SRS Malfunction Indicator Lamp [A1e15]. Indicator lamp must not come on during this check.
Test:
- Connect socket box and multimeter, jiggle or move connectors. Test readings must remain constant.
Remedy:
- Replace connector sleeves.

Cause:
- Screws at airbag positive or negative wiring harness loose.
Remedy:
- Tighten screws.

Cause:
- Insufficient contact pressure of carbons.
Remedy:
- Check ease of movement of contact carbons. Replace carbons.

Cause:
- ETR with airbag control module [N2/2] faulty.
Test:
- Connect a new control module and check airbag and emergency tensioning retractor system with SRS Malfunction Indicator Lamp.
Remedy:
- Replace control module.

Cause:
- Airbag or ETR unit has been activated.
Remedy:
- Replace parts.

Cause:
- Pulse readout is 10 (without airbag being activated).
Remedy:
- Replace ETR with airbag control module; in addition, attach ground cable shoe of airbag wiring harness to lowest point.

Cause:
- Shorted-to-ground cable-to-data-link connector [X11/4] contact 6.
Remedy:
- Replace cable.

Cause:
- Connector of driver's or passenger's seat belt buckle not plugged in.
Remedy:
- Plug in connector.

Cause:
- Undervoltage
Tests:
- Test power supply (11-14 Volts).
- Test Battery and/or Generator.
Remedy:
- Replace needed components.

Cause:
- Open circuit in wiring to slip rings [X28/4-slip rings].
Remedy:
- Replace slip rings.




COMPLAINT: NOISES FROM AIRBAG UNIT ON STEERING WHEEL.
CAUSE
- Failure to observe installation sequence with the result that airbag unit is not properly adjusted and centered.
REMEDY
- Loosen Torx screws and align airbag unit on the steering wheel so that it is positioned evenly. Screw in both Torx screws a few turns then tighten left-hand screw to the specified torque (6 Nm). Next, pull the airbag unit on the right slightly away from the steering wheel and tighten right-hand screw likewise to the specified torque (6 Nm).


COMPLAINT: SRS MALFUNCTION INDICATOR LAMP FLICKERS, COMES ON OCCASIONALLY OR COMES ON AND REMAINS ON.
^ CAUSE
- Film of grease on slip ring of steering wheel.
REMEDY
- Clean slip ring thoroughly (also behind tracks). Wash off with cleaning petroleum, blow out and rub dry with lint-free cloth. Install new slip ring if necessary.

^ CAUSE
- Open circuit in connection cable at outer slip ring.
REMEDY
- Replace slip ring.

^ CAUSE
- "Cold solder point" on wiring harness.
TEST
- Test wiring harness with socket box and multimeter. Jiggle or move connectors of wiring harness when performing test. Test readings must remain constant.
REMEDY
- Solder cable correctly.

^ CAUSE
- Sleeves at connectors widened with the result that pre-tension to mating piece is insufficient.
TEST
- Jiggle or move 10-pin connector of test coupling [X11/13] during test cycle -4 to 20 seconds- conducted by SRS Malfunction Indicator Lamp [A1e15]. Indicator lamp must not come on during this check.
TEST
- Connect socket box and multimeter, jiggle or move connectors. Test readings must remain constant.
REMEDY
- Replace connector sleeves.

^ CAUSE
- Screws at airbag positive or negative wiring harness loose.
REMEDY
- Tighten screws.

^ CAUSE
- Insufficient contact pressure of carbons.
REMEDY
- Check ease of movement of contact carbons. Replace carbons.

^ CAUSE
- ETR with airbag control module [N2/2] faulty.
TEST
- Connect a new control module and check airbag and emergency tensioning retractor system with SRS Malfunction Indicator Lamp.
REMEDY
- Replace control module.

^ CAUSE
- Airbag or ETR unit has been activated.
REMEDY
- Replace parts.

^ CAUSE
- Pulse readout is 10 (without airbag being activated).
REMEDY
- Replace ETR with airbag control module; in addition, attach ground cable shoe of airbag wiring harness to lowest point.

^ CAUSE
- Shorted-to-ground cable-to-data-link connector [X11/4] contact 6.
REMEDY
- Replace cable.

^ CAUSE
- Connector of driver's or passenger's seat belt buckle not plugged in.
REMEDY
- Plug in connector.

^ CAUSE
- Undervoltage
TESTS
- Test power supply (11-14 Volts).
- Test Battery and/or Generator.
REMEDY
- Replace needed components.

^ CAUSE
- Open circuit in wiring to slip rings [X28/4-slip rings].
REMEDY
- Replace slip rings.