Pinpoint Test R: LFC 16 DTC B2909
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test R: LFC 16 DTC B2909
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Normal Operation
The BTS operates in conjunction with the Occupant Classification System Module (OCSM). The OCSM interprets a variable voltage signal provided by the Belt Tension Sensor (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 from no tension low voltage (approximately 0.95 volt) to high tension high voltage (approximately 3.8 volts).
The OCSM monitors the BTS and circuitry for faults. If the OCSM detects a fault on any of the BTS circuits, it will store DTC B2909 in memory and send a message to the Restraints Control Module (RCM), which will store DTC B2290 in memory and send a message to the Instrument Cluster (IC) module to flash a Lamp Fault Code (LFC) 16 on the air bag warning indicator.
The Occupant Classification Sensor (OCS) system components (seat wiring harness, seat cushion foam pad, bladder with pressure sensor and OCSM are calibrated to each other and are serviced as an assembly. The OCS system components are not to be installed separately with the exception of the BTS.
NOTE: When monitoring fault and/or resistance PIDs with the scan tool, it may take up to 2 seconds for the scan tool display to update.
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
- OCSM
PINPOINT TEST R: LFC 16 DTC B2909
WARNING: Do not handle, move or change the original horizontal mounting position of the restraints control module (RCM) while the RCM is connected and the ignition switch is ON. Failure to follow this instruction may result in the accidental deployment of the Safety Canopy(R) and cause serious personal injury or death.
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 taking 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: To identify between a production OCS system and an OCS system service kit, inspect the OCSM electrical connector. 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.
NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
NOTE: 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.
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R1 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 B2909 Fault PIDs.
- Refer to PID list in Normal Operation to view B2909 fault PIDs.
- Do any OCSM on-demand B2909 fault PIDs indicate a fault?
Yes
This is a hard fault. The fault condition is still present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test.
Using the on-demand fault PIDs recorded, GO to the appropriate pinpoint test step.
Vehicles with a production OCS system,
For 2909_31_OD (Front Passenger Side BTS Circuit Fault), GO to R2.
For 2909_28_OD (Front Passenger's Side BTS Short to Battery), GO to R8.
For 2909_30_OD (Front Passenger's Side BTS Open Circuit), GO to R9.
For 2909_29_OD (Front Passenger Side BTS Short to Ground), GO to R10.
Vehicles with an OCS system service kit, GO to R11.
No
This is an intermittent fault when present as a continuous memory DTC only (DTC not retrieved on-demand). The fault condition is not present at this time. GO to R20.
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R2 CHECK THE 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: Passenger Side Air Bag Module C337.
- Disconnect: Passenger Safety Belt Buckle Pretensioner Electrical Connector.
- Disconnect: BTS C3238.
- 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 the 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 R21.
No
GO to R3.
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R3 CHECK THE 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 the resistance between OCSM C3285, harness side and BTS C3238, harness side using the following chart.
- Are resistances less than 0.5 ohm?
Yes
GO to R4.
No
REPAIR circuit LR142 (YE/BU), VR210 (BU/BN) or RR142 (GN). GO to R21.
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R4 CHECK CIRCUITS LR142 (YE/BU), VR210 (BU/BN) and RR142 (GN) FOR A SHORT TO GROUND
- Measure the 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 resistances greater than 10,000 ohms?
Yes
GO to R5.
No
REPAIR circuit LR142 (YE/BU), VR210 (BU/BN) or RR142 (GN). GO to R21.
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R5 CHECK FOR A SHORT BETWEEN CIRCUITS LR142 (YE/BU), VR210 (BU/BN) AND RR142 (GN)
- Measure the resistance between OCSM C3285, harness side using the following chart.
- Are resistances greater than 10,000 ohms?
Yes
GO to R6.
No
REPAIR circuit LR142 (YE/BU), RR142 (GN) or VR210 (BU/BN). GO to R17.
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R6 CHECK THE 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 the voltage between BTS C3238-1, circuit LR142 (YE/BU), harness side and C3238-2, circuit RR142 (GN), harness side.
- Is the voltage approximately 5 volts?
Yes
GO to R7.
No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor - Service Kit Occupant Classification Sensor - Service Kit.
GO to R21.
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R7 CHECK THE 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 C3238 pin 1, circuit LR142 (YE/BU), harness side and pin 1, circuit LR142 (YE/BU), component side.
- Connect a fused jumper lead between BTS C3238 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 the voltage between BTS C3238 pin 3, circuit VR210 (BU/BN), component side and ground as the tension of the BTS is varied.
- 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 R19.
No
INSTALL a new BTS. GO to R21.
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R8 CHECK THE 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 C3238.
- 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 the voltage between BTS:
- C3238-2, circuit RR142 (GN), harness side and ground.
- C3238-3, circuit VR210 (BU/BN), harness side and ground.
- C3238-1, circuit LR142 (YE/BU), harness side and ground.
- Are the voltages less than 0.2 volt for C3238-2 and C3238-3 and approximately 5 volts for C3238-1?
Yes
GO to R19.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to R21.
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R9 CHECK THE BTS CIRCUIT 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 C3238.
- Disconnect: OCSM C3285.
- Measure the resistance between OCSM C3285, harness side and BTS C3238, harness side using the following chart.
- Are resistances less than 0.5 ohm?
Yes
GO to R17.
No
REPAIR circuit RR142 (GN), VR142 (YE/BU) or VR210 (BU/BN). GO to R21.
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R10 CHECK THE 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: OCSM C3285.
- Measure the 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 resistances greater than 10,000 ohms?
Yes
GO to R19.
No
REPAIR circuit RR142 (GN), VR210 (BU/BN) or LR142 (YE/BU). GO to R21.
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R11 CHECK THE 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 visual inspection of the OCS 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 R21.
No
Using the fault PIDs recorded in Step P1, GO to the appropriate pinpoint test step.
For BTS with a circuit fault (2909_31_OD), GO to R12.
For BTS with a short to battery fault (2909_28_OD), GO to R15.
For BTS with a short to ground fault (2909_29_OD), GO to R16.
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R12 CHECK THE BTS CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: BTS C3238.
- 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 the voltage between BTS:
- C3238-2, circuit RR142 (GN), harness side and ground.
- C3238-3, circuit VR210 (BU/BN), harness side and ground.
- C3238-1, circuit LR142 (YE/BU), harness side and ground.
- Are the voltages less than 0.2 volt for C3238-2 and C3238-3 and approximately 5 volts for C3238-1?
Yes
GO to R13.
No
REPAIR circuit RR142 (GN), VR210 (BU/BN) or LR142 (YE/BU). GO to R21.
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R13 CHECK THE 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 the resistance between BTS:
- C3238-3, circuit VR210 (BU/BN), harness side and ground.
- C3238-2, circuit RR142 (GN), harness side and ground.
- C3238-1, circuit LR142 (YE/BU), harness side and ground.
- Are resistances greater than 10,000 ohms for C3238-1 and C3238-3 and less than 5 ohms for C3238-2?
Yes
GO to R14.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to R21.
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R14 CHECK CIRCUITS LR142 (YE/BU), VR210 (BU/BN) AND RR142 (GN) FOR A SHORT
- Measure the resistance between BTS:
- C3238-1, circuit LR142 (YE/BU), harness side and C3238-3, circuit VR210 (BU/BN), harness side.
- C3238-1, circuit LR142 (YE/BU), harness side and C3238-2, circuit RR142 (GN), harness side.
- C3238-3, circuit VR210 (BU/BN), harness side and C3238-2, circuit RR142 (GN), harness side.
- Are resistances greater than 10,000 ohms?
Yes
GO to R17.
No
REPAIR circuit LR142 (YE/BU), RR142 (GN) or VR210 (BU/BN). GO to R21.
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R15 CHECK THE BTS CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: BTS C3238.
- 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 the voltage between BTS:
- C3238-2, circuit RR142 (GN), harness side and ground.
- C3238-3, circuit VR210 (BU/BN), harness side and ground.
- C3238-1, circuit LR142 (YE/BU), harness side and ground.
- Are the voltages less than 0.2 volt for C3238-2 and C3238-3 and approximately 5 volts for C3238-1?
Yes
GO to R17.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to R21.
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R16 CHECK THE BTS CIRCUITS FOR A SHORT TO GROUND
- Disconnect: BTS C3238.
- Measure the resistance between BTS:
- C3238-3, circuit VR210 (BU/BN), harness side and ground.
- C3238-2, circuit RR142 (GN), harness side and ground.
- C3238-1, circuit LR142 (YE/BU), harness side and ground.
- Are resistances greater than 10,000 ohms for C3238-1 and C3238-3 and less than 5 ohms for C3238-3?
Yes
GO to R17.
No
REPAIR circuit VR210 (BU/BN), RR142 (GN) or LR142 (YE/BU). GO to R21.
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R17 CHECK THE OCSM OUTPUT
- 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 the voltage between BTS C3238-1, circuit LR142 (YE/BU), harness side and C3238-2, circuit RR142 (GN), harness side.
- Is the voltage approximately 5 volts?
Yes
GO to R18.
No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor - Service Kit Occupant Classification Sensor - Service Kit.
GO to R21.
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R18 CHECK THE 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 C3238 pin 1, circuit LR142 (YE/BU), harness side and pin 1, circuit LR142 (YE/BU), component side.
- Connect a fused jumper lead between BTS C3238 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 the voltage between BTS C3238 pin 3, circuit VR210 (BU/BN), component side and ground as the tension of the BTS is varied.
- 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 R19.
No
INSTALL a new BTS. GO to R21.
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R19 CONFIRM THE BTS FAULT
NOTE: Make sure all restraint system sensor electrical connectors and the RCM electrical connectors are connected before carrying out the on-demand 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 C3238.
- 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.
- 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 B2909 Fault PIDs.
- Refer to PID list in Normal Operation to view B2909 fault PIDs.
- Do any OCSM on-demand B2909 fault PIDs indicate a fault?
Yes
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor - Service Kit Occupant Classification Sensor - Service Kit.
GO to R21.
No
In the process of diagnosing the fault, the fault condition has become intermittent.
CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition 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 intermittent wiring, terminal or connector concerns found. GO to R21.
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R20 CHECK BTS CIRCUIT FAULT PIDs 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 B2909 Fault PIDs.
- Refer to PID list in Normal Operation to view B2909 fault PIDs.
- Do any OCSM on-demand B2909 fault PIDs indicate a fault?
Yes
This is a hard fault. The fault condition is now present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test.
Using the on-demand fault PIDs recorded, GO to the appropriate pinpoint test step.
Vehicles with a production OCS system,
For 2909_31_OD (Front Passenger Side BTS Circuit Fault), GO to R2.
For 2909_28_OD (Front Passenger's Side BTS Short to Battery), GO to R8.
For 2909_30_OD (Front Passenger's Side BTS Open Circuit), GO to R9.
For 2909_29_OD (Front Passenger Side BTS Short to Ground), GO to R10.
Vehicles with an OCS system service kit, GO to R11.
No
The fault is not present and cannot be recreated at this time.
CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition 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 intermittent wiring, terminal or connector concerns found. GO to R21.
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R21 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 DTCs have been resolved. GO to the DTC Charts for pinpoint test direction. [1][2]Diagnostic Trouble Code Descriptions
No
CLEAR all RCM and OCSM DTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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