Pinpoint Test X: DTC B2909
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Test X: DTC B2909
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Lamp Fault Codes (LFCs)
The following Lamp Fault Codes (LFCs) indicate the specific faults associated with DTC B2909:
- LFC 7-13 - Front Passenger Side Belt Tension Sensor Circuit Fault
- LFC 7-14 - Front Passenger Side Belt Tension Sensor Short to Ground
Normal Operation
The Belt Tension Sensor (BTS) operates in conjunction with the Occupant Classification System (OCS) system. The Occupant Classification System Module (OCSM) interprets a variable voltage signal provided by the BTS sensor to identify the possible presence of a child safety seat in the front passenger seat.
The OCS system components (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. If a new OCS system, OCS system component or seat cushion foam pad are needed, a new OCS system service kit must be installed as an assembly. Refer to Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) Description and Operation.
The OCSM monitors the BTS circuits for faults. If a fault is detected 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, depending on the fault, flash a LFC on the air bag warning indicator. The secondary air bag warning chime will also be activated.
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 monitor 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 X: DTC B2909
WARNING: Remove restraint system diagnostic tools from the vehicle prior to road testing. If tools are not removed, the supplemental restraint system (SRS) device may not deploy in a crash. Failure to follow this instruction may result in serious personal injury or death in a crash and possibly violate vehicle safety standards.
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 disassemble or tamper with safety belt buckle/retractor pretensioners or adaptive load limiting retractors or probe the electrical connectors. 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: 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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X1 RETRIEVE SRS DTCs
- Enter the following diagnostic mode on the scan tool: Self-Test - RCM.
- Enter the following diagnostic mode on the scan tool: DataLogger - RCM - View and Record All B2909 Fault PIDs.
- Refer to PID list in Normal Operation to view B2909 fault PIDs.
- Do any on-demand B2909 fault PIDs indicate a fault?
Yes
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 fault PIDs recorded, GO to the appropriate pinpoint test step.
For 2909_31_OD (Front Passenger Side Belt Tension Sensor Circuit Fault) (LFC 7-13), GO to X2.
For 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground) (LFC 7-14), GO to X4.
No
This is an intermittent fault when present as a Continuous Memory Diagnostic Trouble Code (CMDTC) only (DTC not retrieved on demand). The fault condition is not present at this time. GO to X9.
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X2 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 Seat Side Air Bag Module C316 .
- Connect: Restraint System Diagnostic Service Tool 418-133 to Passenger Seat Side Air Bag Module C316.
- Disconnect: Passenger Safety Belt Buckle Switch and BTS C3066.
- Disconnect: OCSM C3043.
- 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:
- C3043-11, circuit 2088 (TN/RD), harness side and ground.
- C3043-13, circuit 2090 (DB/OG), harness side and ground.
- C3043-12, circuit 2089 (OG/BK), harness side and ground.
- Is voltage present on any circuits?
Yes
REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG). GO to X10.
No
GO to X3.
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X3 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:
- C3043-11, circuit 2088 (TN/RD), harness side and passenger safety belt buckle switch and BTS C3066-4, circuit 2088 (TN/RD), harness side.
- C3043-13, circuit 2090 (DB/OG), harness side and passenger safety belt buckle switch and BTS C3066-5, circuit 2090 (DB/OG), harness side.
- C3043-12, circuit 2089 (OG/BK), harness side and passenger safety belt buckle switch and BTS C3066-6, circuit 2089 (OG/BK), harness side.
- Are the resistances less than 0.5 ohm?
Yes
GO to X5.
No
REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG).
GO to X10.
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X4 CHECK CIRCUITS 2088 (TN/RD), 2089 (OG/BK) AND 2090 (DB/OG) 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: RCM C310a and C310b.
- Disconnect: Passenger Safety Belt Buckle and BTS C3066.
- Disconnect: OCSM C3043.
- Measure the resistance between OCSM:
- C3043-11, circuit 2088 (TN/RD), harness side and ground.
- C3043-12, circuit 2089 (OG/BK), harness side and ground.
- C3043-13, circuit 2090 (DB/OG), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to X5.
No
REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG). GO to X10.
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X5 CHECK CIRCUITS 2088 (TN/RD), 2089 (OG/BK) AND 2090 (DB/OG) FOR A SHORT TO EACH OTHER
- Measure the resistance between the OCSM:
- C3043-11, circuit 2088 (TN/RD), harness side and C3043-12, circuit 2089 (OG/BK), harness side.
- C3043-11, circuit 2088 (TN/RD), harness side and C3043-13, circuit 2090 (DB/OG), harness side.
- C3043-12, circuit 2089 (OG/BK), harness side and C3043-13, circuit 2090 (DB/OG), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to X6.
No
REPAIR circuit 2088 (TN/RD), 2090 (DB/OG) and/or 2089 (OG/BK). GO to X10.
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X6 CHECK THE OCSM OUTPUT
- Connect: OCSM C3043 .
- Disconnect: Passenger Seat Side Air Bag Module C316 .
- Connect: Restraint System Diagnostic Service Tool 418-133 to Passenger Seat Side Air Bag Module C316.
- 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 passenger safety belt buckle switch and BTS C3066-4, circuit 2088 (TN/RD), harness side and C3066-5, circuit 2090 (DB/OG), harness side.
- Is the voltage approximately 5 volts?
Yes
GO to X7.
No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to X10.
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X7 CHECK BTS VOLTAGE OUTPUT
- Ignition OFF.
- Connect a fused jumper lead between passenger safety belt buckle switch and BTS C3066 pin 4, circuit 2088 (TN/RD), harness side and pin 4, circuit 2088 (TN/RD), component side.
- Connect a fused jumper lead between passenger safety belt buckle switch and BTS C3066 pin 5, circuit 2090 (DB/OG), harness side and pin 5, circuit 2090 (DB/OG), component side.
- Ignition ON.
- Measure the voltage between passenger safety belt buckle switch and BTS C3066 pin 6, circuit 2089 (OG/BK), 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 X8.
No
INSTALL a new BTS. REFER to Safety Belt System Safety Belt Buckle - Front. GO to X10.
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X8 CONFIRM THE BTS FAULT
NOTE: Make sure all Restraint System Diagnostic Service Tools, sensor electrical connectors, OCS system components 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: Passenger Safety Belt Buckle Switch and BTS C3066.
- 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 - RCM.
- Enter the following diagnostic mode on the scan tool: DataLogger - RCM - View and Record All B2909 Fault PIDs.
- Refer to PID list in Normal Operation to view B2909 fault PIDs.
- Do any on-demand B2909 fault PIDs indicate a fault?
Yes
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to X10.
No
In the process of diagnosing the fault, the fault condition has become intermittent. CHECK for causes of the intermittent fault in the areas previously worked in, particularly the pins and terminals of electrical connectors that were disconnected. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. 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 X10.
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X9 CHECK FOR AN INTERMITTENT FAULT
- Enter the following diagnostic mode on the scan tool: Self-Test - RCM.
- Enter the following diagnostic mode on the scan tool: DataLogger - RCM - View and Record All B2909 Fault PIDs.
- Refer to PID list in Normal Operation to view B2909 fault PIDs.
- Do any on-demand B2909 fault PIDs indicate a fault?
Yes
The fault condition is now present. The fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self-test.
Using the fault PIDs recorded, GO to the appropriate pinpoint test step.
For 2909_31_OD (Front Passenger Side Belt Tension Sensor Circuit Fault) (LFC 7-13), GO to X2.
For 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground) (LFC 7-14), GO to X4.
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 intermittent wiring, terminal or connector concerns found. GO to X10.
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X10 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 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 - RCM.
- Are any RCM DTCs retrieved on-demand during self-test?
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 continuous memory DTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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