B2441

Seat-belt Tensioner, Driver





Fault symptoms
Airbag warning lamp on.

Conditions
The following conditions are applicable to the respective diagnostic trouble codes:

B2444
- The resistance measured by the control module is lower than 1.41 ohms for 20 s.
- Fault diagnosis will not be carried out if diagnostic trouble code B2447 or B2448 has been generated.

B2446
- The resistance measured by the control module is higher than 3.90 ohms for 10 s.
- The resistance measured by the control module is higher than 225 ohms for 160 ms.
- Fault diagnosis will not be carried out if diagnostic trouble code B2447 or B2448 has been generated.

B2447
- The voltage applied to control module pin 2 is lower than 1.5 V for 1.25 s.

B2448
- The voltage applied to control module pin 1 is higher than 3.5 V for 1.25 s.

Action

1. Check the wiring harness between the control module and the left belt tensioner.




- Turn the ignition switch to the OFF position.
- Check the wiring's 2-pin connector for an open circuit and/or pin slide-out and rectify it as necessary.




- Connect the reference resistor 86 12 095 to the 2-pin connector.




- Undo the connector: Control Module Airbag: (331)
- Check and if necessary rectify pins 8 and 9 with respect to open circuit/pin slide-out.
- Connect a break-out box (BOB) to the mains.
- Select the trouble code that has been generated

B2446, B2444
- Go to step 2.
B2447, B2448
- Go to step 3.

2. Check the wiring harness between the control module and the left belt tensioner.
- Take a resistance reading




- Red feed cable: Control module Airbag: 8
- Black feed cable: Control module Airbag: 9
- The value should be 2 - 4 ohms

Test results OK?

YES
- Change: Belt tensioner, left
- Go to step 5.
NO
- Repair or replace the wiring.
- Go to step 5.

3. Check the wiring harness between the control module and the left belt tensioner.
- Take a resistance reading




- Red feed cable: Control module Airbag: 8




- Black test lead: Car battery: B-.
- The resistance should be infinite (O.L.).

Test results OK?

YES
- Go to step 4.
NO
- Repair or replace the wiring.
- Go to step 5.

4. Check the wiring harness between the control module and the left belt tensioner.
- Take a resistance reading




- Red feed cable: Control module Airbag: 9




- Black test lead: Car battery: B-.
- The resistance should be infinite (O.L.).

Test results OK?

YES
- Change: Belt tensioner, left
- Go to step 5.
NO
- Repair or replace the wiring.
- Go to step 5.

5. Final check




- Clear the diagnostic trouble codes in all systems.
- Perform a driving cycle:
- Drive the car with varying engine loads and at varying engine speeds for five minutes.
- Evaluate the driving cycle:




- Check that the diagnostic trouble code has not recurred.

Test results OK?

YES
- The steps taken to rectify the fault were correct.
NO
- See Before Changing A Control Module