Pinpoint Test N: DTC B2691
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests - Restraints Control Module (RCM)
Pinpoint Test N: DTC B2691
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Normal Operation
The driver and passenger safety belt buckles are equipped with safety belt buckle switches. The safety belt buckles are comprised of integrated circuits called Hall-effect switches. The safety belt buckle switches indicate to the Restraints Control Module (RCM) whether the safety belt buckles are buckled or unbuckled.
The RCM supplies current to the safety belt buckle switch. Current flows through the switch, buckled or unbuckled to ground. The RCM will sense the difference in this current draw, 6 mA (unbuckled) or 15 mA (buckled), and use this information in determining the deployment rate of the dual-stage driver and passenger air bag modules.
If the RCM detects an open circuit or short to voltage fault, it will store DTC B2691 in memory and send a message to the Instrument Cluster (IC) module to illuminate the air bag warning indicator.
- DTC B2691 Seat Belt Buckle Switch Circuit Fault, Front Driver's Side - If the RCM detects an open or short to voltage on the driver safety belt buckle switch circuit, it will set this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Driver safety belt buckle switch
- RCM
PINPOINT TEST N: DTC B2691
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) 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.
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N1 RETRIEVE RCM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - RCM .
- Was DTC B2691 retrieved on-demand during self-test?
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. GO to N2.
No
This is an intermittent fault when present as a Continuous Memory Diagnostic Trouble Code (CMDTC). The fault condition is not present at this time. GO to N7.
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N2 CHECK DRIVER SAFETY BELT BUCKLE SWITCH 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: RCM C310a and C310b.
- Disconnect: Driver Safety Belt Buckle Switch C3296.
- Measure resistance between RCM C310b-25, circuit CR201 (BU/OG), harness side and driver safety belt buckle switch C3296-2, circuit CR201 (GN/BU), harness side.
- Is the resistance less than 0.5 ohm?
Yes
GO to N3.
No
REPAIR circuit CR201 (GN/BU). GO to N8.
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N3 CHECK DRIVER SAFETY BELT BUCKLE SWITCH GROUND CIRCUIT FOR AN OPEN
- Measure resistance between driver safety belt buckle switch C3296-1, circuit GD127 (BK/BU), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to N4.
No
REPAIR circuit GD127 (BK/BU). GO to N8.
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N4 CHECK DRIVER SAFETY BELT BUCKLE SWITCH CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: Driver Seat Side Air Bag Module C328.
- 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 driver safety belt buckle switch C3296-2, circuit CR201 (GN/BU), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit CR201 (GN/BU). GO to N8.
No
GO to N5.
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N5 CHECK THE DRIVER SAFETY BELT BUCKLE SWITCH FOR A FAULT STATUS CHANGE (CIRCUIT FAULT INDICATED)
NOTE: This pinpoint test step will attempt to change the fault reported by the RCM by inducing a different fault condition. If the fault reported changes, this indicates the RCM is functioning correctly and is not the source of the fault.
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Connect: RCM C310a and C310b.
- Connect a fused jumper wire between driver safety belt buckle switch C3096-2, circuit CR201 (GN/BU), harness side and C3296-1, circuit GD127 (BK/BU), harness 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.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM .
- DIAGNOSTIC TIP: When viewing on-demand DTCs with the driver safety belt buckle switch circuits shorted together, a short to ground fault would normally be retrieved.
- Did the on-demand DTC change from B2691 to B2434?
Yes
INSTALL a new driver safety belt buckle assembly. REFER to Seat Belt Systems. GO to N8.
No
GO to N6.
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N6 CONFIRM RCM FAULT
NOTE: Make sure all restraint system components, sensor electrical connectors 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.
- Remove the fused jumper wire from driver safety belt buckle switch C3296.
- Connect: Driver Safety Belt Buckle Switch C3296.
- 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 .
- Was DTC B2691 retrieved on-demand during self-test?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to N8.
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. 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 N7.
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N7 CHECK FOR AN INTERMITTENT FAULT
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Driver Seat Side Air Bag Module C328.
- 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 .
- Was DTC B2691 retrieved on-demand during self-test?
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 on-demand self test. GO to N2.
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, cycling the ignition 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 N8.
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N8 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.
- NOTE: When selecting Restraints from the Self Test menu, DTCs will be retrieved from the RCM and OCSM.
- Are any RCM and/or Occupant Classification System Module (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. Diagnostic Trouble Code Tests and Associated Procedures
No
CLEAR all RCM and OCSM DTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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