Pinpoint Test K: LFC 42/DTC B2296
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test K: LFC 42/DTC B2296
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Normal Operation
The Restraints Control Module (RCM) monitors the impact sensor circuits for the following:
- Open circuit
- Unacceptable voltage
- Short to ground
The RCM will set and store DTC B2296 in memory if any of these conditions are detected. If the RCM detects one of the following faults on any impact sensor circuits, it will store DTC B2296 in memory and send a message to the Instrument Cluster (IC) module to flash Lamp Fault Code (LFC) 42 (or higher priority code if one exists) on the air bag warning indicator.
a Fault PIDs that end in OD indicate an on-demand status and are associated with DTC B2296. Fault PIDs that end in CM indicate continuous memory status and are associated with DTC B2296.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Impact sensor
- Incorrect sensor mounting
- RCM
PINPOINT TEST K: LFC 42/DTC B2296
WARNING: Always tighten the fasteners of the restraints control module (RCM) and impact sensor (if equipped) to the specified torque. Failure to do so may result in incorrect restraint system operation, which increases the risk of personal injury or death in a crash.
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: Do not probe any impact sensor. The impact sensor cannot be tested using a multi-meter.
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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K1 RETRIEVE RCM DTCs
- 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 B2296 Fault PIDs.
- Refer to the PID list in Normal Operation to view B2296 fault PIDs.
- Do any on-demand DTC B2296 fault PIDs indicate a fault?
Yes
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during self-test.
For 2296_18_OD, INSTALL a new driver/center front impact severity sensor. REFER to Front Impact Severity Sensor Service and Repair. GO to K13.
For 2296_3_OD, GO to K2.
For 2296_4_OD, GO to K4.
For 2296_5_OD or 2296_19_OD, GO to K6.
No
This is an intermittent fault when present as a Continuous Memory Diagnostic Trouble Code (CMDTC) only. GO to K12.
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K2 CHECK FRONT IMPACT SEVERITY SENSOR 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: Front Impact Severity Sensor C177.
- Disconnect: RCM C310A and C310B.
- 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 front impact severity sensor:
- C177-2, circuit CR139 (VT/WH), harness side and ground.
- C177-1, circuit RR139 (YE), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR circuit CR139 (VT/WH) or RR139 (YE). GO to K13.
No
GO to K3.
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K3 CHECK FRONT IMPACT SEVERITY SENSOR 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:
- RCM C310A-11, circuit CR139 (VT/WH), harness side and front impact severity sensor C177-2, circuit CR139 (VT/WH), harness side.
- RCM C310A-12, circuit RR139 (YE), harness side and front impact severity sensor C177-1, circuit RR139 (YE), harness side.
- Are the resistances less than 0.5 ohm?
Yes
GO to K10.
No
REPAIR circuit CR139 (VT/WH) or RR139 (YE). GO to K13.
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K4 CHECK FRONT IMPACT SEVERITY SENSOR CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Front Impact Severity Sensor C177.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Measure the resistance between front impact severity sensor:
- C177-2, circuit CR139 (VT/WH), harness side and ground.
- C177-1, circuit RR139 (YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to K5.
No
REPAIR circuit CR139 (VT/WH) or RR139 (YE). GO to K13.
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K5 CHECK FOR A SHORT BETWEEN FRONT IMPACT SEVERITY SENSOR CIRCUITS
- Measure the resistance between front impact severity sensor C177-2, circuit CR139 (VT/WH), harness side and C177-1, circuit RR139 (YE), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to K10.
No
REPAIR circuits CR139 (VT/WH) and RR139 (YE). GO to K13.
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K6 INSPECT THE FRONT IMPACT SEVERITY SENSOR MOUNTING AND MOUNTING SURFACE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Inspect the front impact severity sensor mounting and make sure that the retaining bolt is fully seated and tightened correctly.
- Remove the front impact severity sensor. Refer to Front Impact Severity Sensor Service and Repair.
- Visually inspect the front impact severity sensor and mounting surface for damage, corrosion or dirt.
- Was the front impact severity sensor damaged, a significant amount of corrosion or dirt found, attached to the mounting surface incorrectly or was the impact sensor bolt not fully seated and tightened correctly?
Yes
If the front impact severity sensor was not attached to the mounting surface correctly, REINSTALL the sensor correctly and CLEAN or REPAIR the mounting surface as necessary. GO to K13.
If the front impact severity sensor was damaged, INSTALL a new front impact severity sensor. GO to K13.
No
GO to K7.
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K7 CHECK FRONT IMPACT SEVERITY SENSOR 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: RCM C310A and C310B.
- Disconnect: Front Impact Severity Sensor C177.
- Measure the resistance between:
- RCM C310A-11, circuit CR139 (VT/WH), harness side and front impact severity sensor C177-2, circuit CR139 (VT/WH), harness side.
- RCM C310A-12, circuit RR139 (YE), harness side and front impact severity sensor C177-1, circuit RR139 (YE), harness side.
- Are the resistances less than 0.5 ohm?
Yes
GO to K8.
No
REPAIR circuit CR139 (VT/WH) or RR139 (YE). GO to K13.
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K8 CHECK FRONT IMPACT SEVERITY SENSOR 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 front impact severity sensor:
- C177-2, circuit CR139 (VT/WH), harness side and ground.
- C177-1, circuit RR139 (YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to K9.
No
REPAIR circuit CR139 (VT/WH) or RR139 (YE). GO to K13.
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K9 CHECK FRONT IMPACT SEVERITY SENSOR 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: Front Impact Severity Sensor C177.
- Disconnect: RCM C310A and C310B.
- 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 front impact severity sensor:
- C177-2, circuit CR139 (VT/WH), harness side and ground.
- C177-1, circuit RR139 (YE), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR circuit CR139 (VT/WH) or RR139 (YE). GO to K13.
No
GO to K10.
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K10 CHECK THE FRONT IMPACT SEVERITY SENSOR
- 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.
- Install a known good front impact severity sensor.
- 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 B2296 Fault PIDs.
- Refer to the PID list in Normal Operation to view B2296 fault PIDs.
- Do any on-demand DTC B2296 fault PIDs indicate a fault?
Yes
GO to K11.
No
Fault corrected. GO to K13.
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K11 CONFIRM THE RCM FAULT
NOTE: Make sure all restraint system components and the RCM electrical connectors are connected before carrying out 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.
- Install the original sensor.
- 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 B2296 Fault PIDs.
- Refer to the PID list in Normal Operation to view B2296 fault PIDs.
- Does the original on-demand DTC B2296 fault PID indicate a fault?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to K12.
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 K13.
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K12 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 B2296 Fault PIDs.
- Refer to the PID list in Normal Operation to view B2296 fault PIDs.
- Do any on-demand DTC B2296 fault PIDs indicate a fault?
Yes
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 2296_18_OD, INSTALL a new driver/center front impact severity sensor. REFER to Front Impact Severity Sensor Service and Repair. GO to K13.
For 2296_3_OD, GO to K2.
For 2296_4_OD, GO to K4.
For 2296_5_OD or 2296_19_OD, GO to K6.
No
INSPECT the affected impact sensor and mounting surface for damage, corrosion or dirt. INSPECT the wiring, terminals and connectors for damage, corrosion or dirt. 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 K13.
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K13 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 RCM DTCs retrieved indicating a fault?
Yes
Do not clear any DTCs until all DTCs have been resolved. GO to the DTC Chart for pinpoint test direction. Diagnostic Trouble Code Tests and Associated Procedures
No
CLEAR all RCM CMDTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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