Pinpoint Test V: LFC 49 DTC C1981
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test V: LFC 49 DTC C1981
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Normal Operation
As part of the Supplemental Restraint System (SRS), the driver seat is equipped with a seat track position sensor. The seat track position sensor is comprised of integrated circuits called Hall-effect switch. The seat track position sensor indicates to the Restraints Control Module (RCM) the position of the driver seat, forward or rearward.
The RCM supplies current to the seat track position sensor. Current flows through the switch, both in the forward or rearward seat position to ground. The RCM will sense the difference in this current draw, 6 mA (forward) or 15 mA (rearward), and use this information in determining the deployment rate of the dual-stage driver air bag module. If the RCM detects current out of range, it will set a DTC.
If the RCM detects a circuit fault, it will store DTC C1981 in memory and send a message to the Instrument Cluster (IC) module to flash a Lamp Fault Code (LFC) 49 on the air bag warning indicator.
NOTE: When monitoring fault and/or resistance PIDs with the scan tool, it may take up to 2 seconds for the scan tool display to update.
- DTC C1981 Front Driver's Seat Track Position Switch Circuit Fault - If the RCM detects an open or short to battery on the driver seat track position sensor circuit for greater than 2.5 seconds, it will set this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- RCM
PINPOINT TEST V: LFC 49 DTC C1981
WARNING: Do not handle, move or change the original horizontal mounting position of the restraints control module (RCM) while the RCM is connected and the ignition switch is ON. Failure to follow this instruction may result in the accidental deployment of the Safety Canopy(R) and cause serious personal injury or death.
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 probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. 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 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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V1 RETRIEVE RCM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was RCM DTC C1981 retrieved on-demand during the self-test?
Yes
This is a hard fault. 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 V2.
No
This is an intermittent fault when present as a continuous memory DTC only (DTC not retrieved on demand). The fault condition is not present at this time. GO to V6.
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V2 CHECK CIRCUIT VR215 (YE/VT) 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 Seat Track Position Sensor C356.
- Measure the resistance between RCM C310b-23, circuit VR215 (YE/VT), harness side and driver seat track position sensor C356-2, circuit RR137 (BU/GY), harness side.
- Is resistance less than 0.5 ohm?
Yes
GO to V3.
No
REPAIR circuit VR215 (YE/VT). GO to V7.
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V3 CHECK CIRCUIT GD133 (BK) FOR AN OPEN
- Measure the resistance between driver seat track position sensor C356-1, circuit GD133 (BK), harness side and ground.
- Is resistance less than 5 ohms?
Yes
GO to V4.
No
REPAIR circuit GD133 (BK). GO to V7.
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V4 CHECK CIRCUITS VR215 (YE/VT) FOR A SHORT TO VOLTAGE
- Disconnect: Driver Side Air Bag C3226.
- Disconnect: Driver Safety Belt Buckle Pretensioner Electrical 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.
- Measure the voltage between driver seat track position sensor C356-2, circuit VR215 (YE/VT), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit VR215 (YE/VT). GO to V7.
No
GO to V5.
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V5 CONFIRM THE RCM FAULT
NOTE: Make sure all restraint system component electrical connectors and the RCM electrical connectors are connected before carrying out the on-demand 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: RCM C310a and C310b.
- Connect: Driver Seat Track Position Sensor C356.
- 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 RCM DTC C1981 retrieved on-demand during the self-test?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to V7.
No
In the process of diagnosing the fault, the fault condition has become intermittent.
CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and 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 V7.
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V6 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 C3226.
- 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 RCM DTC C1981 retrieved on-demand during the self-test?
Yes
This is a hard fault. 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 V2.
No
CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and 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 V7.
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V7 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.
- Are any RCM and/or 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. [1][2]Diagnostic Trouble Code Descriptions
No
CLEAR all RCM and OCSM DTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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