Preparation For Test
Preliminary work:
Diagnosis Diagnostic Trouble Code (DTC) Memory. DTCM - Diagnostic Trouble Code Memory
Diagnosis - Fault Frequency, Time Span. FFTS - Fault Frequency Time Span
Diagnosis - Actual Values. AV - Actual Values
Preparation for Test:
CAUTION!
Risk of injury if airbag units and ETR units are ignited accidentally or if stored with the opening end facing downward which may cause the accidentally ignited components to fly about causing injury. Danger to persons also exists if the components are disposed of by cutting apart with cutting torches or other cutting/separation devices. Danger also exists if disposing the untriggered units via refuse collection or via smelting/carbonizing companies.
Protective measures/supervision:
- Place removed airbag unit with the opening side facing downward.
- Allow only properly trained dealer staff to supervise, purchase, transport, store, test/replace any of the SRS components.
- Install all airbag or ETR units once pulled from the parts department.
- Protect all airbag or ETR units from any sparks, open flame, or temperatures above 100° C.
- Do not transport airbag or ETR units in the passenger compartment, rather transport securely in their original packaging in the trunk.
- Do not allow oil, grease or cleaning agents come in contact with the airbag or ETR units
- Perform SRS tests only with approved test equipment (such as HHT). while installed in the vehicle without occupants.
Refer to Electrical Wiring Diagrams:
- When reconnecting the vehicle battery or any outside electrical source, with the ignition turned ON, do not allow any occupants inside the vehicle.
- Airbag or ETR units which have been dropped from a height greater than 18 inches must be replaced.
- Prior to disposing the airbag or ETR units, the units must be made un-useable by discharging.
- In order to render the airbag and ETR unit un-useable, the specially made discharge harness must be used and at the same time maintain a safe distance of at least 33 feet from the units being discharged.
Prior to undertaking any chassis/body repairs, installation/repair work on airbag and ETR units, or any components which come in contact with the airbag and ETR units, or are part of the electrical circuit of airbag and ETR units (such as installation of the steering wheel), the following conditions must be met:
- Remove ignition key.
- Disconnect any outside source of electrical circuit (i.e. battery charger).
- When performing welding operations, disconnect the connector from the SRS control module.
1. Check fuses.
2. Battery voltage > 11 V.
3. Insert vehicle specific test module into Hand-Held Tester (HHT).
4. Connect (HHT) as per connection diagram. Connection and Use of Test Equipment
CAUTION !
Do not connect battery trickle charger.
Initial Display
Display appears approximately 5 seconds after the HHT is connected to the vehicle (example: Model 140).
Further information on use of the HHT will now appear on the display.
Special Tools
Test equipment:
DESCRIPTION Brand, model, etc.
Digital multimeter Fluke models 23, 77 III, 83, 85, 87
Shop-made Test Cables
Parts Required for Test:
1 Connection piece 034 545 63 28
1 Connector 019 545 19 28
2 Wire with 2.5 mm socket (from electrical connector set)
2 Wire with 2.5 mm pin (from electrical connector set)
CAUTION!
All red colored connectors and connections of the airbag squibs are constructed with a short-circuiting bridge. Upon disconnecting, the squib wire and squib are automatically short-circuited, to prevent airbag deployment.
Thus all repairs can be accomplished with only the ignition key removed.
Accessories (for vehicles with ASCR Installed only):
Child seat "Babysafe"
CAUTION!
The battery minus cable must be disconnected and covered, as well as the SRS control module (N2/2) disconnected prior to use of any electrical welding equipment.
Additionally, the previously used SRS test connection is no longer present.
Model 140
10-pole connector, (X11/13, Figure 2) between cockpit and frame floor.
Models 202, 210
2-pole connector, (X28/12, Figure 4) for front passenger airbag between cockpit and frame floor.
Models 170, 210
2-pole connectors, (X35/1 [left front door separation point], X35/2 [right front door separation point]) for left/right side airbag.
Connection Diagram - Socket Box Tester/SRS Control Module Connector
Figure 1
002 Test cable
003 Multimeter
004 Socket box (36-pole socket box shown as example)
1 SRS control module connector
2 Connect and disconnect aid
3 Connect and disconnect lock
Model 140
Connection Diagram - Socket Box Tester/SRS Control Module Connection (10-pole)
Figure 2
002 Test cable
003 Multimeter
004 Socket box
050 Socket box
X11/13 SRS test connection (10-pole)
Connection Diagram - Test Cables/Squib
Plug Connections
Figure 3
003 Test cables with banana plugs
038 Resistance substitution unit
1 Short circuit bridge
2 Connector, part no. 019 545 19 28
3 Test cables with 2.5 mm sockets
A45x1 Horn/airbag clock spring contact connector
X28/8 ETR connector (left seat plug connection) (2-pole)
X28/9 ETR connector (right seat plug connection) (2-pole)
X28/12 Passenger airbag connector
X35/1 Left front door separation point
X35/2 Right front door separation point
X35/41 Left front door separation point
X35/42 Right front door separation point
Connection Diagram - Test Cables/Squib
Plug Connections
Figure 4
003 Test cables with banana plugs
038 Resistance substitution unit
1 Short circuit bridge
2 Connector, part no. 026 545 63 28
3 Test cables with 2.5 mm sockets
Connection Diagram - Resistance Substitution
Unit/Squib Connectors
Figure 5
002 Test cable, part no. 140 589 22 63 00
003 Test cables with banana plugs
038 Resistance substitution unit
R12/1 Left front ETR squib
R12/2 Right front ETR squib
R12/3 Driver AB squib
R12/8 Front passenger AB squib
R12/9 Left side airbag squib
R12/10 Right side airbag squib
Connection Diagram - Side Airbag Sensors
Figure 6
002 Test cable part no. 140 589 22 63 00
003 Multimeter
A53 Left side airbag sensor
A54 Right side airbag sensor
Connection Diagram - Resistance Substitution
Unit with Diode for Simulation of Seat Occupation Recognition
Model 210 shown
Figure 7
002 Test cable, part no. 140 589 22 63 00
003 Test cable with banana plugs
038 Resistance substitution unit
X55/3 Left ESA connector block
X55/4 Right ESA connector block
Connection Diagram - Resistance Substitution Unit with Diode for Simulation of Seat Occupation Recognition
Model 129 shown
Figure 8
002 Test cable, part no. 140 589 22 63 00
003 Test cable with banana plugs
038 Resistance substitution unit
X28/18 Occupied seat recognition connector/ACSR