Pinpoint Test X: DTC B1994/B1995
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test X: DTC B1994/B1995
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Normal Operation
The Restraints Control Module (RCM) continuously monitors the driver seat side air bag module and circuits for resistance out of range.
If a fault is detected, the RCM will store DTC B1994 or B1995 in memory and send a message to the Instrument Cluster (IC) module to illuminate the air bag warning indicator.
The RCM analyzes the deployment loop resistance and uses this measurement in combination with an age correction factor to determine if a fault exists. The value displayed in the PID is the deployment loop resistance as measured by the RCM. If the value displayed is lower or higher than the desired range (refer to diagram below), the RCM can set a DTC. As the deployment loop resistance drifts farther outside the desired range, the chance for a DTC increases. The RCM fault trigger threshold may vary as the vehicle ages. Small variations in resistance can occur due to the effect of road vibrations on terminal fit and/or temperature changes. These variables can result in an intermittent fault. For this reason, the test will require the PID value to be within the desired range before the fault is considered repaired, regardless if the module is reporting an active DTC at the time of diagnosis. Following this direction will help make sure that minor changes in resistance do not create a repeat concern. This test will use a process of elimination to diagnose each part of the deployment loop circuit including:
- Wiring
- Connections
- Driver seat side air bag module
- RCM
- DTC B1994 (Driver Side, Side Mount Airbag Circuit Open) - When the RCM measures greater than the desired resistance range between driver air bag stage 1 circuits, a fault will be indicated.
- DTC B1995 (Driver Side, Side Mount Airbag Low Resistance On Squib) - When the RCM measures less than the desired resistance range between driver air bag stage 1 circuits, a fault will be indicated.
PINPOINT TEST X: DTC B1994/B1995
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 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: 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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X1 RETRIEVE RCM DTCs
NOTE: All RCM diagnosis will be carried out using Continuous Memory Diagnostic Trouble Codes (CMDTCs) and status information. Refer to DTC Fault Reporting and Status Information. DTC Fault Reporting and Status Information
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Select the DTC and view DTC Status information.
- Does the status information for DTC B1994 or B1995 indicate a fault was present at the time of request?
Yes
This fault cannot be cleared until it is corrected and the DTC Status information indicates the fault is no longer present.
GO to X2.
No
This is an intermittent fault. The DTC Status information indicates the fault was not present at time of request. GO to X10.
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X2 CHECK THE DRIVER SEAT SIDE AIR BAG RESISTANCE (DS_AB) PID
- Enter the following diagnostic mode on the scan tool: DataLogger - RCM .
- DS_AB
- Does the PID value read between 1.7 and 2.78 ohms?
Yes
GO to X9.
No
GO to X3.
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X3 CHECK THE DRIVER SEAT SIDE AIR BAG RESISTANCE (DS_AB) PID WHILE CARRYING OUT THE HARNESS TEST
- While monitoring the DS_AB PID, carry out the harness test of the driver seat side air bag module circuits and accessible connectors (including any in-line connectors), by wiggling connectors and flexing the wire harness.
- Does the PID value read between 1.7 and 2.78 ohms while carrying out the harness test?
Yes
DEPOWER the SRS and REPAIR the connector, terminals or wire harness as needed.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
GO to X12.
No
For PID value less than 1.7 ohms, GO to X4.
For PID value greater than 2.78 ohms, GO to X6.
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X4 CHECK THE DRIVER SEAT SIDE AIR BAG FOR A FAULT STATUS CHANGE (LOW RESISTANCE 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.
- Disconnect: Driver Seat Bulkhead Connector.
- 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.
- Select the DTC and view DTC Status information.
- DIAGNOSTIC TIP: When viewing DTCs with the driver seat bulkhead connector disconnected, an numerous circuit faults would normally be retrieved.
- Does the status information for DTC B1995 indicate a fault was present at the time of request?
Yes
GO to X5.
No
GO to X8.
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X5 CHECK FOR A SHORT BETWEEN DRIVER SEAT SIDE AIR BAG CIRCUITS
- 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.
- Measure the resistance between the driver seat side air bag C339A-2, circuit 15S-JA37 (GN/BK), harness side and C339A-1, circuit 91S-JA37 (BK/GN), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to X9.
No
REPAIR circuit 15S-JA37 (GN/BK) or 91S-JA37 (BK/GN). GO to X12.
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X6 CHECK THE DRIVER SEAT SIDE AIR BAG 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: Driver Seat Bulkhead Connector.
- Disconnect: RCM C310A and C310B.
- Measure the resistance between RCM, harness side and driver seat side air bag C339A, harness side using the following chart.
- Are the resistances less than 0.5 ohm?
Yes
GO to X7.
No
REPAIR circuit 15S-JA37 (GN/BK) or 91S-JA37 (BK/GN). GO to X12.
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X7 CHECK THE DRIVER SEAT SIDE MOUNT AIR BAG FOR A FAULT STATUS CHANGE (OPEN 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.
- Connect: RCM C310A and C310B.
- Connect a fused jumper wire between the driver seat side air bag C339A-2, circuit 15S-JA37 (GN/BK), harness side and C339A-1, circuit 91S-JA37 (BK/GN), 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.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Select the DTC and view DTC Status information.
- DIAGNOSTIC TIP: When viewing DTCs with the driver seat side air bag circuits shorted together, a low resistance fault would normally be retrieved.
- Does the status information for DTC B1994 indicate a fault was present at the time of request?
Yes
GO to X9.
No
GO to X8.
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X8 CONFIRM THE DRIVER SEAT SIDE AIR BAG MODULE FAULT
NOTE: Make sure all restraint system components 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 seat bulkhead connector.
- Prior to reconnecting any previously disconnected SRS component:
- inspect connector(s) (including any in-line connectors) for pushed-out, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- inspect RCM C310A and C310B Connector Position Assurance (CPA) lever/lock for correct operation. Refer to Restraints Control Module (RCM) Service and Repair.
- repair any concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
- Connect: Driver Seat Bulkhead Connector.
- 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.
- Select the DTC and view DTC Status information.
- Does the status information for the original DTC indicate a fault was present at the time of request?
Yes
REMOVE the seat side air bag module jumper harness and INSPECT the harness and connector terminals for damage. REFER to Side Air Bag Module Side Air Bag Module. If a concern is found, REPAIR as necessary.
If a concern is not found, INSTALL a new driver seat side air bag module. REFER to Side Air Bag Module Side Air Bag Module. GO to X12.
No
In the process of diagnosing the fault, the fault condition has become intermittent. 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. GO to X10.
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X9 CONFIRM THE RCM FAULT
NOTE: Make sure all restraint system components 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 the driver seat bulkhead connector (if previously installed).
- Prior to reconnecting any previously disconnected SRS component:
- inspect connector(s) (including any in-line connectors) for pushed-out, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- inspect RCM C310A and C310B CPA lever/lock for correct operation. Refer to Restraints Control Module (RCM) Service and Repair.
- repair any concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
- Connect: RCM C310A and C310B (if previously disconnected).
- Connect: Driver Seat Bulkhead Connector.
- 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.
- Select the DTC and view DTC Status information.
- Does the status information for the original DTC indicate a fault was present at the time of request?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to X12.
No
In the process of diagnosing the fault, the fault condition has become intermittent. 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. GO to X10.
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X10 CHECK FOR INTERMITTENT DRIVER SEAT SIDE AIR BAG RESISTANCE (DS_AB) PID LOW RESISTANCE OR OPEN CIRCUIT FAULT
- Enter the following diagnostic mode on the scan tool: DataLogger - RCM .
- DS_AB
- Attempt to recreate the fault by wiggling the connectors (including any in-line connectors) and flexing the wire harness.
- Does the PID value read between 1.7 and 2.78 ohms?
Yes
The fault is not present and cannot be recreated at this time. 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. GO to X11.
No
DEPOWER the SRS and REPAIR as necessary.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
GO to X12.
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X11 CHECK THE HARNESS AND CONNECTORS
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect the driver seat bulkhead connector:
- inspect connector(s) (including any in-line connectors) for corrosion, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- Were any concerns found?
Yes
REPAIR as necessary.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
GO to X12.
No
The fault is not present and cannot be recreated at this time. 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. GO to X12.
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X12 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 - Restraints.
- NOTE: When selecting Restraints from the Self Test menu, DTCs will be retrieved from the RCM and OCSM.
- Select the DTC and view DTC Status information.
- Does the status information for any RCM DTC indicate a fault is present and/or are any OCSM on-demand DTCs retrieved?
Yes
Do not clear any DTCs until all DTC concerns 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 CMDTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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