Pinpoint Test U: DTC C1946
Pinpoint Tests - Supplemental Restraint System (SRS)
Pinpoint Test U: DTC C1946
Refer to Wiring Diagrams Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Normal Operation
The Restraints Control Module (RCM) monitors the driver seat track position sensor circuits. If the RCM detects an open circuit, it will store DTC C1946 in memory and send a message to the Instrument Cluster (IC) module to illuminate the air bag warning indicator.
- DTC C1946 Front Driver's Seat Track Position Switch Circuit Open - If the RCM detects a open on the driver seat track position sensor circuit, it will set this DTC. An open driver seat track position sensor ground circuit will set this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Driver seat track position sensor
- RCM
PINPOINT TEST U: DTC C1946
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 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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U1 RETRIEVE RCM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC C1946 retrieved on-demand during self-test?
Yes
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during self-test. GO to U2.
No
This is an intermittent fault when present as a continuous memory DTC only. The fault condition is not present at this time. GO to U6.
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U2 CHECK DRIVER SEAT TRACK POSITION SENSOR DTCs FOR A CHANGE IN FAULT STATUS
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 Track Position Sensor C356.
- Connect a fused jumper wire between driver seat track position sensor C356-2, circuit VR215 (YE/VT), harness side and C356-1, circuit RR137 (BU/GY), 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 seat track position sensor circuits shorted together, a short to ground fault would normally be retrieved.
- Did the driver seat track position switch on-demand DTC change from C1946 to C1947?
Yes
INSTALL a new driver seat track position sensor. REFER to Seat Position Sensor Service and Repair. GO to U7.
No
GO to U3.
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U3 CHECK DRIVER SEAT TRACK POSITION SENSOR 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.
- Remover the fused jumper wire from the driver seat track position sensor C356.
- Measure resistance between RCM C310b-23, circuit VR215 (YE/VT), harness side and driver seat track position sensor C356-2, circuit VR215 (YE/VT).
- Is the resistance less than 0.5 ohm?
Yes
GO to U4.
No
REPAIR circuit VR215 (YE/VT). GO to U7.
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U4 CHECK DRIVER SEAT TRACK POSITION SENSOR GROUND CIRCUIT FOR AN OPEN
- Measure resistance between driver seat track position sensor C356-1, circuit RR137 (BU/GY) and ground.
- Is the resistance less than 5 ohms?
Yes
GO to U5.
No
REPAIR circuit RR137 (BU/GY). GO to U7.
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U5 CONFIRM THE 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, 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: Driver Seat Track Position Sensor C356.
- Connect: 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.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC C1946 retrieved on-demand during self-test?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to U7.
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. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key 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 wiring, terminal or connector concerns found.
GO to U6.
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U6 CHECK FOR AN INTERMITTENT FAULT
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC C1946 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 self-test. GO to U2.
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. 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 wiring, terminal or connector concerns found. GO to U7.
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U7 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 concerns/faults have been resolved. GO to the DTC Charts for pinpoint test direction. [1][2]Diagnostic Trouble Code Descriptions
No
CLEAR all RCM and OCSM CMDTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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