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Pinpoint Test W: DTC B2909




Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)

Pinpoint Tests

Pinpoint Test W: 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 fault PIDs associated with DTC B2909:

- LFC 7-13 - Belt Tension Sensor Open or Short to Battery
- LFC 7-14 - Belt Tension Sensor Short to Ground

Normal Operation

The Belt Tension Sensor (BTS) operates in conjunction with the Occupant Classification Sensor (OCS) system. The Occupant Classification System Module (OCSM) for the OCS system interprets a variable voltage signal provided by the BTS 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 (seat cushion foam pad, bladder with pressure sensor and OCSM) must be installed as an assembly.

The OCSM monitors the BTS circuits for faults. If a fault is detected on any of the BTS sensor 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 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 W: 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.

NOTICE: Use the correct probe adapter(s) when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.

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.

NOTE: 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

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W1 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 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any 2909 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 on-demand during 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 W2.

For 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground) (LFC 7-14), GO to W4.

No
This is an intermittent fault when present as a CMDTC only (DTC not retrieved on demand). The fault condition is not present at this time.
GO to W9.

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W2 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 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 circuit?

Yes
REPAIR circuit 2088 (TN/RD), circuit 2089 (OG/BK) or 2090 (DB/OG). GO to W10.

No
GO to W3.

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W3 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 3043, harness side and passenger safety belt buckle switch and BTS 3066, harness side using the following chart:









- Are the resistances less than 0.5 ohm?

Yes
GO to W5.

No
REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG).

GO to W10.

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W4 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: 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 W5.

No
REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG). GO to W10.

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W5 CHECK FOR A SHORT BETWEEN CIRCUITS 2088 (TN/RD), 2089 (OG/BK) AND 2090 (DB/OG)


- Measure the resistance between 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 W6.

No
REPAIR circuit 2088 (TN/RD), 2090 (DB/OG) and/or 2089 (OG/BK). GO to W10.

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W6 CHECK THE OCSM OUTPUT


- Connect: OCSM C3043 .
- Disconnect: Passenger Seat Side Air Bag Module C316.
- Connect: Restraint System Diagnostic 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 BTS C3066-4, circuit 2088 (TN/RD), harness side and C3066-5, circuit 2090 (DB/OG), harness side.




- Is voltage approximately 5 volts?

Yes
GO to W7.

No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair.

GO to W10.

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W7 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 4, circuit 2088 (TN/RD), harness side and pin 4, circuit 2088 (TN/RD), component side. and ground as you vary the tension of the BTS.




- Measure the voltage 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 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 W8.

No
INSTALL a new BTS. REFER to Restraint Systems. GO to W10.

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W8 CONFIRM THE BTS FAULT


NOTE: Make sure all restraint system diagnostic tools, sensor electrical connectors, OCSM and the RCM electrical connectors are connected before carrying out the self test. If not, 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 C3043 .
- 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.
- Ignition ON.
- 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 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any 2909 fault PIDs indicate a fault?

Yes
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to W10.

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, terminals or connector concerns found. GO to W10.

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W9 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 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any 2909 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 on-demand during 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 W2.

For 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground) (LFC 7-14), GO to W4.

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, terminals or connector concerns found. GO to W10.

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W10 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 - RCM.
- Are any DTCs retrieved on-demand during self-test?

Yes
Do not clear any DTCs until all DTCs have been resolved. GO to the Supplemental Restraint System (SRS) DTC Chart for pinpoint test direction. Supplemental Restraint System (SRS) DTC Chart

No
CLEAR all CMDTCs. PROVE OUT the SRS. REPAIR is complete. RETURN the vehicle to the customer.

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