Pinpoint Test T: DTC B2909
Pinpoint Tests - Supplemental Restraint System (SRS)
Pinpoint Test T: DTC B2909
Refer to Wiring Diagrams Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Normal Operation
The Belt Tension Sensor (BTS) operates in conjunction with the Occupant Classification Sensor (OCS) system. The Occupant Classification System Module (OCSM) interprets a variable voltage signal provided by the safety BTS to identify the possible presence of a child safety seat in the front passenger seat. The voltage output of the BTS is proportional to the amount of tension applied to the sensor by the belt, no tension low voltage (approximately 0.95 volt) and high tension high voltage (approximately 3.8 volts).
The OCSM checks the BTS circuits for faults. If the OCSM detects one of the following faults on any of the BTS circuits, it will report the failure to the Restraints Control Module (RCM). The RCM will store DTC B2909 in memory and send a message to the Instrument Cluster (IC) module to illuminate the air bag indicator.
a Fault PIDs that end in OD indicate an on-demand status and are associated with on-demand DTC B2909. Fault PIDs that end in CM indicate continuous memory status and are associated with continuous DTC B2909.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- BTS
- OCS system
PINPOINT TEST T: DTC B2909
WARNING: Never probe the electrical connectors on air bag, Safety Canopy(R) or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
WARNING: Never probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. Failure to follow this instruction may result in the accidental deployment of the safety belt pretensioners or adaptive load limiting retractors, which increases the risk of serious personal injury or death.
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test. Inspection and Verification
NOTE: Supplemental Restraint System (SRS) components should only be disconnected or reconnected when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
NOTE: A production OCS system allows the disconnect of the electrical connector from the OCSM. An OCS system service kit has the OCSM electrical connector glued to the module. It cannot and should not be disconnected or altered.
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T1 RETRIEVE OCSM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - OCSM.
- Enter the following diagnostic mode on the scan tool: DataLogger - OCSM - View and Record All 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any OCSM on-demand 2909 fault PIDs indicate a fault?
Yes
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the self-test.
Using the fault PIDs recorded, GO to the appropriate pinpoint test step.
Vehicles with a production OCS system,
for 2909_31_OD (Front Passenger Side Belt Tension Sensor Circuit Fault), GO to T2.
for 2909_28_OD (Front Passenger's Side Belt Tension Sensor Short to Battery), GO to T8.
for 2909_30_OD (Front Passenger's Side Belt Tension Sensor Open Circuit), GO to T9.
for 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground), GO to T10.
Vehicles with a OCS system service kit, GO to T11.
No
This is an intermittent fault when present as a CMDTC only. The fault condition is not present at this time. GO to T21.
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T2 CHECK BTS CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: BTS C389.
- Disconnect: OCSM C3285.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between OCSM:
- C3285-11, circuit LR142 (YE/BU), harness side and ground.
- C3285-13, circuit RR142 (GN), harness side and ground.
- C3285-12, circuit VR210 (BU/BN), harness side and ground.
- Is voltage present on any circuit?
Yes
REPAIR circuit LR142 (YE/BU), VR210 (BU/BN) or RR142 (GN). GO to T22.
No
GO to T3.
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T3 CHECK BTS CIRCUITS FOR AN OPEN
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Measure resistance between OCSM C3285, harness side and BTS C389, harness side using the following chart.
- Are the resistances less than 0.5 ohm?
Yes
GO to T4.
No
REPAIR circuit LR142 (YE/BU), VR210 (BU/BN) or RR142 (GN).
GO to T22.
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T4 CHECK BTS CIRCUITS FOR A SHORT TO GROUND
- Measure resistance between OCSM:
- C3285-11, circuit LR142 (YE/BU), harness side and ground.
- C3285-12, circuit VR210 (BU/BN) harness side and ground.
- C3285-13, circuit RR142 (GN), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to T5.
No
REPAIR circuit LR142 (YE/BU), VR210 (BU/BN) or RR142 (GN). GO to T22.
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T5 CHECK FOR A SHORT BETWEEN BTS CIRCUITS
- Measure resistance between BTS:
- C389-1, circuit LR142 (YE/BU), harness side and C389-3, circuit VR210 (BU/BN), harness side.
- C389-1, circuit LR142 (YE/BU), harness side and C389-2, circuit RR142 (GN), harness side.
- C389-3, circuit VR210 (BU/BN), harness side and C389-2, circuit RR142 (GN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to T6.
No
REPAIR circuit LR142 (YE/BU), RR142 (GN) or VR210 (BU/BN). GO to T18.
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T6 CHECK OCSM OUTPUT
- Connect: OCSM C3285.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between BTS C389-1, circuit LR142 (YE/BU), harness side and C389-2, circuit RR142 (GN), harness side.
- Is voltage approximately 5 volts?
Yes
GO to T7.
No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to T22.
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T7 CHECK BTS VOLTAGE OUTPUT
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Connect a fused jumper lead between BTS C389 pin 1, circuit LR142 (YE/BU), harness side and pin 1, circuit LR142 (YE/BU), component side.
- Connect a fused jumper lead between BTS C389 pin 2, circuit RR142 (GN), harness side and pin 2, circuit RR142 (GN), component side.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between BTS C389 pin 3, circuit VR210 (BU/BN), component side and ground as the tension of the BTS varies.
- Does voltage vary from approximately 0.95 volt with no tension applied to the sensor to approximately 3.8 volts with full tension applied to the sensor?
Yes
GO to T20.
No
INSTALL a new passenger safety belt retractor assembly. REFER to Seat Belt Systems. GO to T22.
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T8 CHECK BTS CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: BTS C389.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between BTS:
- C389-3, circuit VR210 (BU/BN), harness side and ground.
- C389-2, circuit RR142 (GN), harness side and ground.
- C389-1, circuit LR142 (YE/BU), harness side and ground.
- Is there approximately 5 volts for C389-1 and no voltage present on C389-2 and C389-3?
Yes
GO to T20.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T9 CHECK BTS CIRCUITS FOR AN OPEN
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: BTS C389.
- Disconnect: OCSM C3285.
- Measure resistance between OCSM C3285, harness side and BTS C389, harness side using the following chart.
- Are the resistances greater than 10,000 ohms?
Yes
GO to T18.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T10 CHECK BTS CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: BTS C389.
- Measure resistance between BTS:
- C389-1, circuit LR142 (YE/BU), harness side and ground.
- C389-3, circuit VR210 (BU/BN), harness side and ground.
- C389-2, circuit RR142 (GN), harness side and ground.
- Are the resistances greater than 10,000 ohms for C389-1 and C389-3 and less than 5 ohms for C389-2?
Yes
GO to T20.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T11 CHECK BTS CIRCUITS
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Carry out a thorough inspection of the OCS system wiring, terminals and connectors, the BTS wiring, terminals and connectors and the related seat wiring harness and body wiring harness terminals and connectors.
- Were any problems noted?
Yes
REPAIR the seat connectors and wiring as needed. GO to T22.
No
Using the fault PIDs recorded in Step T1, GO to the appropriate pinpoint test step.
For 2909_31_OD (Front Passenger Side Belt Tension Sensor Circuit Fault), GO to T12.
For 2909_30_OD (Front Passenger's Side Belt Tension Sensor Open Circuit), GO to T17.
For 2909_28_OD (Front Passenger's Side Belt Tension Sensor Short to Battery), GO to T15.
For 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground), GO to T16.
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T12 CHECK BTS CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: BTS C389.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between BTS:
- C389-3, circuit VR210 (BU/BN), harness side and ground.
- C389-2, circuit RR142 (GN), harness side and ground.
- C389-1, circuit LR142 (YE/BU), harness side and ground.
- Is there approximately 5 volts for C389-1 and no voltage present on C389-2 and C389-3?
Yes
GO to T13.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T13 CHECK BTS CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Measure resistance between BTS:
- C389-1, circuit LR142 (YE/BU), harness side and ground.
- C389-3, circuit VR210 (BU/BN), harness side and ground.
- C389-2, circuit RR142 (GN), harness side and ground.
- Are the resistances greater than 10,000 ohms for C389-1 and C389-3 and less than 5 ohms for C389-2?
Yes
GO to T14.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T14 CHECK FOR A SHORT BETWEEN BTS CIRCUITS
- Measure resistance between BTS:
- C389-1, circuit LR142 (YE/BU), harness side and C389-3, circuit VR210 (BU/BN), harness side.
- C389-1, circuit LR142 (YE/BU), harness side and C389-2, circuit RR142 (GN), harness side.
- C389-3, circuit VR210 (BU/BN), harness side and C389-2, circuit RR142 (GN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to T18.
No
REPAIR circuit LR142 (YE/BU), RR142 (GN) or VR210 (BU/BN). GO to T22.
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T15 CHECK BTS CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: BTS C389.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between BTS:
- C389-3, circuit VR210 (BU/BN), harness side and ground.
- C389-2, circuit RR142 (GN), harness side and ground.
- C389-1, circuit LR142 (YE/BU), harness side and ground.
- Is there approximately 5 volts for C389-1 and no voltage present on C389-2 and C389-3?
Yes
GO to T18.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T16 CHECK BTS CIRCUITS FOR A SHORT TO GROUND
- Disconnect: BTS C389.
- Measure resistance between BTS:
- C389-1, circuit LR142 (YE/BU), harness side and ground.
- C389-3, circuit VR210 (BU/BN), harness side and ground.
- C389-2, circuit RR142 (GN), harness side and ground.
- Are the resistances greater than 10,000 ohms for C389-1 and C389-3 and less than 5 ohms for C389-2?
Yes
GO to T18.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T17 CHECK BTS CIRCUITS FOR AN OPEN
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: BTS C389.
- Disconnect: OCSM C3285.
- Measure resistance between OCSM C3285, harness side and BTS C389, harness side using the following chart.
- Are the resistances greater than 10,000 ohms?
Yes
GO to T18.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to T22.
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T18 CHECK OCSM OUTPUT
- Connect: OCSM C3285 (if previously disconnected).
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between BTS C389-1, circuit LR142 (YE/BU), harness side and C389-2, circuit RR142 (GN), harness side.
- Is voltage approximately 5 volts?
Yes
GO to T19.
No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to T22.
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T19 CHECK BTS VOLTAGE OUTPUT
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Connect a fused jumper lead between BTS C389 pin 1, circuit LR142 (YE/BU), harness side and pin 1, circuit LR142 (YE/BU), component side.
- Connect a fused jumper lead between BTS C389 pin 2, circuit RR142 (GN), harness side and pin 2, circuit RR142 (GN), component side.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure voltage between BTS C389 pin 3, circuit VR210 (BU/BN), component side and ground as you vary the tension of the BTS.
- Does the voltage vary from approximately 0.95 volt with no tension applied to the sensor to approximately 3.8 volts with full tension applied to the sensor?
Yes
GO to T20.
No
INSTALL a new BTS. REFER to Seat Belt Systems. GO to T22.
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T20 CONFIRM THE BTS FAULT
NOTE: Make sure all restraint system diagnostic tools, sensor electrical connectors and the RCM electrical connector are connected before carrying out the self-test. If not, erroneous DTCs will be recorded.
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Connect: OCSM C3285 (if previously disconnected).
- Connect: BTS C389.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - OCSM.
- Enter the following diagnostic mode on the scan tool: DataLogger - OCSM - View and Record All 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any OCSM on-demand 2909 fault PIDs indicate a fault?
Yes
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to T22.
No
CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. ACTIVATE other systems in the same wire harness. Do not install any new SRS components at this time. SRS components should only be installed when directed to do so in the pinpoint test. REPAIR any wiring, terminal or connector concerns found. GO to T22.
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T21 CHECK FOR AN INTERMITTENT FAULT
- Enter the following diagnostic mode on the scan tool: Self Test - OCSM.
- Enter the following diagnostic mode on the scan tool: DataLogger - OCSM - View and Record All 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any OCSM on-demand 2909 fault PIDs indicate a fault?
Yes
The fault condition is now present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the self-test.
Using the fault PIDs recorded, GO to the appropriate pinpoint test step.
Vehicles with a production OCS system,
for 2909_31_OD (Front Passenger Side Belt Tension Sensor Circuit Fault), GO to T2.
for 2909_28_OD (Front Passenger's Side Belt Tension Sensor Short to Battery), GO to T8.
for 2909_30_OD (Front Passenger's Side Belt Tension Sensor Open Circuit), GO to T9.
for 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground), GO to T10.
Vehicles with a OCS system service kit, GO to T11.
No
CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. ACTIVATE other systems in the same wire harness. Do not install any new SRS components at this time. SRS components should only be installed when directed to do so in the pinpoint test. REPAIR any wiring, terminal or connector concerns found. GO to T22.
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T22 CHECK FOR ADDITIONAL SRS DTCs
- Ignition OFF.
- WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
- Reconnect all SRS components (if previously disconnected).
- If previously directed to depower the SRS, repower the SRS. Do notprove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - Restraints.
- Are any RCM and/or OCSM DTCs retrieved indicating a fault?
Yes
Do not clear any DTCs until all concerns/faults have been resolved. GO to the DTC Charts for pinpoint test direction. [1][2]Diagnostic Trouble Code Descriptions
No
CLEAR all RCM and OCSM CMDTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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