Pinpoint Test U: DTC B2438
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test U: DTC B2438
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
Lamp Fault Codes (LFCs)
The following Lamp Fault Code (LFC) indicates the specific fault associated with DTC B2438:
- LFC 7-2 - Passenger Seat Belt Buckle Switch Circuit Short to Ground
Normal Operation
As part of the Supplemental Restraint System (SRS), the safety belt buckles are equipped with Hall-effect switches. The safety belt switches indicate to the Restraints Control Module (RCM) whether the safety belts are connected or disconnected. Refer to Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) Description and Operation.
The RCM checks the passenger safety belt buckle switch circuits for faults. If the RCM detects a short to ground fault, it will store DTC B2438 in memory, flash LFC 7-2 on the air bag warning indicator.
- DTC B2438 Passengers Seat Belt Buckle Switch Short to Ground - If the RCM detects a short to ground on the passenger safety belt buckle circuit, it will set this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Passenger safety belt buckle switch
- RCM
PINPOINT TEST U: DTC B2438
WARNING: Remove restraint system diagnostic tools from the vehicle prior to road testing. If tools are not removed, the supplemental restraint system (SRS) device may not deploy in a crash. Failure to follow this instruction may result in serious personal injury or death in a crash and possibly violate vehicle safety standards.
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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U1 CHECK FOR ON-DEMAND AND CONTINUOUS DTCs
- Enter the following diagnostic mode on the scan tool: Self-Test - RCM.
- Was DTC B2438 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 U2.
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 U5.
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U2 CHECK CIRCUIT 1514 (RD/BK) 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.
- Disconnect: RCM C310a and C310b.
- Disconnect: Passenger Safety Belt Buckle Switch and Belt Tension Sensor (BTS) C3066.
- Measure the resistance between passenger safety belt buckle switch and BTS C3066-1, circuit 1514 (RD/BK), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to U3.
No
REPAIR circuit 1514 (RD/BK). GO to U6.
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U3 CHECK THE PASSENGER SAFETY BELT BUCKLE SWITCH
- Connect: RCM C310a and C310b.
- Install a known good passenger safety belt buckle.
- 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 B2438 retrieved on-demand during self-test?
Yes
GO to U4.
No
Fault corrected. GO to U6.
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U4 CONFIRM THE RCM FAULT
NOTE: Make sure all Restraint System Diagnostic Service Tools, 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.
- Reinstall the original passenger safety belt buckle.
- 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 B2438 retrieved on-demand during self-test?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to U6.
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 intermittent wiring, terminal or connector concerns found. GO to U6.
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U5 CHECK FOR AN INTERMITTENT FAULT
- Ignition OFF.
- Enter the following diagnostic mode on the scan tool: Self-Test - RCM.
- Was DTC B2438 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 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. 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 U6.
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U6 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 on-demand during self-test?
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 continuous memory DTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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