SRS-232
Diagnostic Trouble Code (DTC) SRS-232 and Diagnostic Trouble Code (DTC) SRS-242DTC SRS-232 = Left seat belt tensioner, open-circuit or capacitance too low
DTC SRS-242 = Right seat belt tensioner, open-circuit or capacitance too low
Special tools:
- 998 8695
- Volvo Scan Tool (ST)
DTC conditions
If resistance in the circuit is too high or capacitance too low for over 10 seconds, the diagnostic trouble code (DTC) SRS-232 or diagnostic trouble code (DTC) SRS242 is stored.
Cause of fault
Resistance too high.
- Open-circuit in SRS ignition cable or connectors between left or right seat belt tensioner and SRS sensor module.
- Open-circuit in left or right seat belt tensioner (resistance in igniter too high).
Capacitance too low.
- Capacitance too low or open-circuit in the SRS ignition cable igniter connector capacitor.
Fault symptoms
No symptoms apart from the SRS warning lamp coming on.
WARNING: There is a risk that the seat belt tensioner will not work if this DTC is posted.
Action
The fault can be found by a process of elimination.
WARNING: Under no circumstances use an ohmmeter or other live measuring instrument to take readings on a disconnected non-deployed pyrotechnical seat belt tensioner. This could deploy the seat belt tensioner.
NOTE: Follow the operations described in this chapter carefully and carry out operations in the correct order.
Checking Diagnostic Trouble Code (DTC) And Type Of Fault
Before starting to remove components, the Volvo Scan Tool (ST) should be used to check whether the fault is permanent or intermittent.
- Connect the Volvo Scan Tool (ST). Reading and Clearing Diagnostic Trouble Codes
- Read off diagnostic trouble code (DTC).
- Clear diagnostic trouble code (DTC). Diagnostic trouble codes (DTC) SRS-232 or SRS-242 cannot be cleared if the fault is permanent.
If diagnostic trouble code (DTC) could not be cleared (the fault persists):
The fault is permanent.
- Continue with disconnecting connector from pyrotechnical seat belt tensioner.
If the diagnostic trouble code (DTC) could be cleared:
The fault is not permanent. The fault could be intermittent.
Attempt to provoke the intermittent fault at every step of the fault tracing process by shaking connectors and cabling while taking readings.
- Continue with disconnecting connector from pyrotechnical seat belt tensioner.
Disconnecting Connector From Pyrotechnical Seat Belt Tensioner
- Make a note of radio code if anti-theft coded radio installed.
- Ignition off.
- Disconnect battery negative lead.
For left seat belt tensioner (diagnostic trouble code (DTC) SRS-232):
- Remove left B-post panel in accordance with EG4.
For right seat belt tensioner (diagnostic trouble code (DTC) SRS-242):
- Remove right B-post panel. Pyrotechnical Seat Belt Tensioner - Replacement
For left and right seat belt tensioners:
- Fold back sill trim panel and disconnect connector from seat belt tensioner.
WARNING: Under no circumstances use an ohmmeter or other live measuring instrument to take readings on a disconnected non-deployed pyrotechnical seat belt tensioner. This could deploy the seat belt tensioner!
- Continue checking.
Checking DTCs With The Seat Belt Tensioner Replaced By Special Tool 9988695
- Install special tool 9988695 to SRS ignition cable igniter connector.
NOTE: The special tool should be checked and faultless. If the tool is defective it will cause errors in the diagnosis and make fault-tracing harder. If in doubt check the special tooL. Calibrating Special Tool 998 8695
- Switch ignition to position II.
- Connect battery negative lead.
- Read off diagnostic trouble code (DTC).
- Erase diagnostic trouble code (DTC). Diagnostic trouble codes (DTC) SRS-232 or SRS-242 can be erased if the fault is in the disconnected seat belt tensioner.
If the diagnostic trouble code (DTC) could be erased:
No fault detected by the SRS on-board diagnostic (OBD) system with the seat belt tensioner disconnected and replaced by special tool 9988695.
The fault is probably in the seat belt tensioner.
One last check should be made before replacing the seat belt tensioner.
- Continue with connecting connector to the pyrotechnical seat belt tensioner.
If diagnostic trouble code (DTC) could not be erased (the fault persists):
The fault persists even with the seat belt tensioner disconnected. This means that the seat belt tensioner is OK.
The fault is probably in the SRS ignition cable.
- Continue with checking SRS sensor module connector.
Connecting Connector To The Pyrotechnical Seat Belt Tensioner
- Ignition off.
- Disconnect battery negative lead.
- Remove special tool 9988695.
- Connect seat belt tensioner connector.
WARNING: Under no circumstances use an ohmmeter or other live measuring instrument to take readings on a disconnected non-deployed pyrotechnical seat belt tensioner. This could deploy the seat belt tensioner!
- Continue checking.
Checking Diagnostic Trouble Code (DTC) With The Seat Belt Tensioner Connected
- Switch ignition to position II.
- Connect battery negative lead.
- Read off diagnostic trouble code (DTC). Diagnostic trouble codes (DTC) SRS-232 or SRS-242 should be stored if the fault is in the seat belt tensioner.
If diagnostic trouble code (DTC) SRS-242 or SRS-232 are obtained:
The open-circuit is in the seat belt tensioner.
^ Replace right or left seat belt tensioner. Pyrotechnical Seat Belt Tensioner - Replacement
If no diagnostic trouble code (DTC) is present:
The SRS on-board diagnostic (OBD) system has not detected a fault with the seat belt tensioner connected.
The fault could be intermittent in the SRS ignition cable.
- Continue checking.
Disconnecting Connector From Pyrotechnical Seat Belt Tensioner
- Ignition off.
- Disconnect battery negative lead.
- Disconnect connector from seat belt tensioner.
WARNING: Under no circumstances use an ohmmeter or other live measuring instrument to take readings on a disconnected non-deployed pyrotechnical seat belt tensioner. This could deploy the seat belt tensioner!
- Continue checking.
Checking SRS Sensor Module Connector
- Ignition off.
- Disconnect battery negative lead.
- Expose and remove SRS sensor module connector. SRS Sensor Module - Replacement
CAUTION: Never touch the sensor module pins. There is a risk of static discharge which could damage the sensor module.
- Check cable terminals in the female connector half and male sensor module connector half.
Cable terminals must not be damaged or pressed back.
- Install and remove connector from sensor module.
Check that the connector locks into the sensor module.
If the female and male connector halves are OK:
- Continue checking SRS ignition cable resistance.
If the male sensor module connector half is defective:
^ Replace sensor module. SRS Sensor Module - Replacement
If the female connector half is defective:
^ Replace SRS cable harness.
Checking SRS Ignition Cable Resistance
- ignition off.
- Remove special tool 9988695.
For left seat belt tensioner (diagnostic trouble code (DTC) SRS-232):
- Connect an ohmmeter between connecting socket terminal 1 on the sensor module connector and terminal 1 on the igniter connector.
The ohmmeter should read approx. 0 ohms.
NOTE: If the ohmmeter test pins are too big to fit into the connector terminal holes, insert a thin metal rod (or a piece of stripped cable) with a maximum diameter of 1 mm, and take readings from that. Take care not to damage the connector cable terminals.
- Connect an ohmmeter between connecting socket terminal 2 on the sensor module connector and "service hole" (see arrow in Figure) on the igniter connector.
The ohmmeter should read approx. 0 ohms.
For right seat belt tensioner (diagnostic trouble code (DTC) SRS-242):
- Connect an ohmmeter between connecting socket terminal 3 on the sensor module connector and terminal 1 on the igniter connector.
The ohmmeter should read approx. 0 ohms.
NOTE: If the ohmmeter test pins are too big to fit into the connector terminal holes, insert a thin metal rod (or a piece of stripped cable) with a maximum diameter of 1 mm, and take readings from that. Take care not to damage the connector cable terminals.
- Connect an ohmmeter between connecting socket terminal 4 on the sensor module connector and "service hole" (see arrow in Figure) on the igniter connector.
The ohmmeter should read approx. 0 ohms.
If the readings are OK for each seat belt tensioner:
The fault is probably in the SRS ignition cable igniter connector capacitor, or in the sensor module.
- Continue with checking capacitor in the igniter connector.
If the readings are abnormal for each seat belt tensioner:
If any ohmmeter reading is infinity there is an open-circuit in the SRS ignition cable.
^ Replace SRS cable harness.
Checking Capacitor In The Igniter Connector
Resistance check
NOTE: If there is a measuring instrument with a capacitance measuring facility use "Alternative Capacitance Check" (below).
An ohmmeter can be used to check the capacitor in the SRS ignition cable igniter connector.
- Ignition off.
- Connect measuring instrument terminals between the connector "service hole" and terminal 2 right connecting pin. See connection in Figure. (The capacitor will charge.)
The ohmmeter reading should increase rapidly and stop at infinity.
- Reverse the position of the ohmmeter positive and negative terminals and connect them to the connector as above. See connection in Figure. (The capacitor will discharge and charge.)
The ohmmeter reading should drop rapidly to approx. 0 ohms and then increase to infinity.
Alternative Capacitance Check
A measuring instrument with a capacitance measuring facility can be used to check the capacitor in the SRS ignition cable igniter connector.
- Ignition off.
- Connect measuring instrument terminals between the connector "service hole" and terminal 2 right connecting pin. See connection in Figure.
The measuring instrument should read between 0.46 microF and 0.48 microF.
If the reading is OK:
There is no open-circuit in the capacitor.
- Continue with checking resistance in the ignition cabling and sensor module.
If the reading is abnormal:
If the ohmmeter reading is constantly high without dropping or increasing there is an open-circuit in the capacitor.
^ Replace SRS cable harness.
Checking Resistance In The Ignition Cabling And Sensor Module
- Connect SRS sensor module connector
- Connect an ohmmeter between terminal 1 and the "service hole" (see arrow in Figure) on the igniter connector.
The ohmmeter should read approx. 47 kohms.
If the reading is OK:
SRS ignition cabling and sensor module are OK.
The fault is in the SRS ignition cable igniter connector capacitor (capacitance too low).
^ Replace SRS cable harness.
If the reading is abnormal:
If the ohmmeter reads infinity there is a open-circuit in the SRS sensor module.
^ Replace sensor module. SRS Sensor Module - Replacement