SAAB WIS ONLINE

B2443, B2448

B2443, B2448

Seat belt tensioner, driver / Seat belt tensioner, passenger, short circuit to battery plus

The reference resistor is available in two versions. A newer, part no. 86 12 095 , and an older, part no. 84 71 153 . The new type has closer tolerance limits and should be used for more reliable diagnosis. The illustrations in the following chapter show the older type of reference resistor.
















Diagnostic procedure


1. Connect the diagnostic tool. Note the diagnostic trouble code and type of fault.


P=permanent fault, I=intermittent fault.

If the fault is permanent:

Go to point 3.

If the fault is intermittent:

Go to point 2.

2. The fault is intermittent. Try to provoke the fault at each test section in the continued fault diagnosis.

Move the connectors and cables and turn the steering wheel while testing.

Go to point 3.

3. Turn off the ignition and remove the negative cable from the battery. Undo the bolts securing the steering wheel airbag. Unplug the connector from the back of the airbag and connect the reference resistor 84 71 153 to the connector.


On cars with airbag on passenger side;

3.a. Remove the glove-box and unplug the connector on the back of the passenger airbag.

3.b. Connect the reference resistor 84 71 153 to the connector.

Remove the trim on the B-pillars. Unplug the connectors to the seat belt tensioners. Connect reference resistor 84 71 153 to the connector.

Go to point 4.

4. Refit the negative cable to the battery and turn on the ignition. Clear the fault codes. Turn off the ignition and turn it on again, wait for at least 10 seconds with the ignition on.


Check to see if the diagnostic trouble code returns.

If the diagnostic trouble code returns:

Go to point 7.

If the diagnostic trouble code does not return:

The fault is in the driver or passenger seat belt tensioner. Perform an extra check as described in point 5.

5. Turn off the ignition and remove the negative battery cable. Remove the reference resistor from the seat belt tensioner connector on the driver's side and connect the seat belt tensioner.


Refit the negative cable on the battery and turn on the ignition. Wait for at least 10 seconds with the ignition on.

Check to see if the diagnostic trouble code returns.

If the diagnostic trouble code returns:

Turn off the ignition. Remove the negative battery cable and change the seat belt tensioner. Then go to point 13.

If the diagnostic trouble code does not return:

The fault is in the seat belt tensioner on the passenger side. Perform an extra check as described in point 6.

6. Turn off the ignition and remove the negative battery cable. Reconnect the reference resistor on the seat belt tensioner connector on the driver's side.


Remove the reference resistor form the seat belt connector on the passenger side and connect the seat belt tensioner.

Refit the negative cable on the battery and turn on the ignition. Wait for at least 10 seconds with the ignition on.

Check to see if the diagnostic trouble code returns.

If the diagnostic trouble code returns:

Turn off the ignition, remove the negative battery cable and change the passenger seat belt tensioner. Then go to point 13.

If the diagnostic trouble code does not return:

Turn off the ignition and remove the negative battery cable. Unplug the connector from the seat belt tensioner and then go to point 7.

7. Turn off the ignition and remove the reference resistor from the two seat belt tensioner connectors. Expose the SRS control module. Unplug the connector from the SRS control module and connect a BOB to the wiring harness. Turn on the ignition.


Test of driver's side seat belt tensioner:

Connect a voltmeter between connection 1 on BOB and a good grounding point. Then connect the voltmeter between connection 2 on BOB and a good grounding point. In both cases, the voltmeter should read 0 V.

If the value is OK:

Go to point 10.

If the value differs:

Go to point 8.

8. Unplug the 4-pin connector on the floor tunnel under the carpet, approx. 20 cm in front of the SRS control module.


Measure the resistance in the wiring harness between SRS control module and the 4-pin connector:

Left-hand drive cars (LHD):

Connect a voltmeter between sleeve 1 in the connector female and a good grounding point. Then connect a voltmeter between sleeve 2 in the connector female and a good grounding point.

Right-hand drive cars (RHD):

Connect a voltmeter between sleeve 3 in the connector female and a good grounding point. Then connect a voltmeter between sleeve 4 in the connector female and a good grounding point.

In both cases, the voltmeter should read 0 V.

If the value is OK:

Go to point 9.

If the value differs:

If any of the readings indicates a voltage, there is an overload to battery voltage in the wiring harness between the 4-pin connector and the SRS control module connector. Locate the cause and rectify the fault.

Then go to point 13.

9. Measure the voltage in the wiring harness between the seat belt tensioner and the 4-pin connector:


Left-hand drive cars (LHD):

Connect a voltmeter between pin 1 in the connector male and a good grounding point. Then connect a voltmeter between pin 2 in the connector male and good grounding point.

Right-hand drive cars (RHD):

Connect a voltmeter between pin 3 in the connector male and a good grounding point. Then connect a voltmeter between pin 4 in the connector male and good grounding point.

In both cases, the voltmeter should read 0 V.

If the value is OK:

Go to point 13.

If the value differs:

If any of the readings indicates a voltage, there is an overload to battery voltage in the wiring harness between the seat belt tensioner connector and the 4-pin connector. Locate the cause and rectify the fault.

Then go to point 13.

10. Test of passenger side seat belt tensioner:


Connect the voltmeter between connection 3 on the BOB and a good grounding point. Then connect the voltmeter between connection 4 on the BOB and a good grounding point. In both cases, the voltmeter should read 0 V.

If the value is OK:

Go to point 13.

If the value differs:

Go to point 11.

11. Unplug the 4-pin connector on the floor tunnel under the carpet, approx. 20 cm in front of the SRS control module.


Measure the voltage in the wiring harness between the SRS control module and the connector:

Left-hand drive cars (LHD):

Connect a voltmeter between sleeve 3 in the connector female and a good grounding point. Then connect a voltmeter between sleeve 4 in the connector female and a good grounding point.

Right-hand drive cars (RHD):

Connect a voltmeter between sleeve 1 in the connector female and a good grounding point. Then connect a voltmeter between sleeve 2 in the connector female and a good grounding point.

In both cases, the voltmeter should read 0 V.

If the value is OK:

Go to point 12.

If the value differs:

If any of the readings indicates a voltage, there is an overload to battery voltage in the wiring harness between the 4-pin connector and the SRS control module connector. Locate the cause and rectify the fault.

Then go to point 13.

12. Measure the voltage in the wiring harness between the seat belt tensioner and the 4-pin connector:


Left-hand drive cars (LHD):

Connect a voltmeter between pin 3 in the connector male and a good grounding point. Then connect a voltmeter between pin 4 in the connector male and good grounding point.

Right-hand drive cars (RHD):

Connect a voltmeter between pin 1 in the connector male and a good grounding point. Then connect a voltmeter between pin 2 in the connector male and good grounding point.

In both cases, the voltmeter should read 0 V.

If the value is OK:

Go to point 13.

If the value differs:

If any of the readings indicates a voltage, there is an overload to battery voltage in the wiring harness between the seat belt tensioner connector and the 4-pin connector. Locate the cause and rectify the fault.

Then go to point 13.

13. Turn off the ignition and remove the negative cable on the battery. Remove the reference resistor and plug in all the connectors and the connector to its original components. Reconnect the negative cable on the battery and turn on the ignition.


Clear the fault code. Turn off the ignition and turn it on again. Wait for 10 seconds with the ignition on.

Check to see if the diagnostic trouble code returns.

If the diagnostic trouble code returns:

Go to section: Procedure for replacing the control module .

If the diagnostic trouble code does not return:

Restore the car.