Pinpoint Test S: DTC B2984/B2987
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test S: DTC B2984/B2987
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), this vehicle is equipped a deployable steering column. The Restraints Control Module (RCM) will deploy (collapse) the steering column during a frontal collision when seat position information and other parameters reach predetermined limits. Refer to Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) Description and Operation.
The RCM continuously monitors the deployable steering column circuits (loop) for an acceptable resistance range, unacceptable voltage and shorts to ground. The RCM will set on-demand and store a DTC (B2984, B2985, B2986 or B2987) in memory if any of these conditions are detected. If the RCM detects a fault, it will send a message to the Instrument Cluster (IC) module to illuminate the air bag warning indicator.
As the RCM continuously monitors deployable steering column circuits for resistance, it expects a normal resistance between 1.31 to 4.29 ohms.
If a loop resistance is between 0.9 and 1.31 or between 4.29 and 5 ohms, there exists a strong potential for an intermittent fault, a DTC may or may not set. The RCM will also set an on-demand DTC B2984 or B2987 respectfully if the loop resistance is less than 0.9 ohm or greater than 5 ohms.
- DTC B2984 (Deployable Steering Column Circuit Open) - If the RCM detects an open on the deployable steering column circuits, it will set this DTC.
- DTC B2987 (Deployable Steering Column Circuit Resistance Low on Squib) - If the RCM detects loop resistance less than 0.9 ohm on the deployable steering column circuits, it will set this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Deployable steering column
- RCM
PINPOINT TEST S: DTC B2984/B2987
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.
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: 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.
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.
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S1 RETRIEVE RCM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC B2984 or B2987 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 S2.
No
This is an intermittent fault when present as a CMDTC only. The fault condition is not present at this time. GO to S10.
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S2 CHECK THE DEPLOYABLE STEERING COLUMN
- Enter the following diagnostic mode on the scan tool: DataLogger - RCM - PID.
- Enter the following diagnostic mode on the scan tool: COL_RES (Deployable Column Resistance) Resistance PID .
- Does the resistance PID value read between 1.31 and 4.29 ohms?
Yes
GO to S9.
No
GO to S3.
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S3 CHECK THE COL_RES (DEPLOYABLE COLUMN RESISTANCE) RESISTANCE PID WHILE CARRYING OUT A HARNESS TEST
NOTE: A resistance PID that reads between 0.9 and 1.31 ohms or between 4.29 and 5 ohms may or may not set an on-demand DTC yet indicates a strong potential of an intermittent fault condition. Make sure to thoroughly check wire harness(es), connectors and terminals as they are the likely source of the fault condition.
- Continue monitoring the COL_RES (Deployable Column Resistance) resistance PID while carrying out a harness test of the deployable column circuits and accessible connectors (including any inline connectors), by wiggling connectors and flexing the wire harness.
- Does the resistance PID value read between 1.31 and 4.29 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 S11.
No
If the deployable column resistance PID is less than 1.31 ohms, GO to S7.
If the deployable column resistance PID is greater than 4.29 ohms, GO to S4.
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S4 CHECK THE DEPLOYABLE COLUMN 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: Deployable Steering Column C2318.
- Connect a fused jumper wire between deployable steering column C2318 pin-1, harness side and pin-2, 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.
- DIAGNOSTIC TIP: When viewing on-demand DTCs with the deployable steering column circuits shorted together, a low resistance fault (B2987) would normally be retrieved.
- Did the RCM on-demand fault change from B2984 to B2987?
Yes
INSTALL a new steering column assembly. REFER to Steering Column. GO to S11.
No
GO to S5.
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S5 CHECK DEPLOYABLE STEERING COLUMN 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.
- Remove the fused jumper wire from deployable steering column C2318.
- Measure resistance between RCM C310a-19, circuit CR139 (VT/WH), harness side and deployable steering column C2318-1, circuit CR139 (VT/WH), harness side.
- Measure resistance between RCM C310a-20, circuit RR139 (YE), harness side and deployable steering column C2318-2, circuit RR139 (YE), harness side.
- Are resistances less than 0.5 ohm?
Yes
GO to S6.
No
REPAIR circuit CR139 (VT/WH) or RR139 (YE). GO to S11.
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S6 CHECK CIRCUIT RR139 (YE) FOR AN OPEN
- Measure resistance between RCM C310a-20, circuit RR139 (YE), harness side and deployable steering column C2318-2, circuit RR139 (YE), harness side.
- Is resistance less than 0.5 ohm?
Yes
GO to S9.
No
REPAIR circuit RR139 (YE). GO to S11.
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S7 CHECK FOR A SHORT BETWEEN DEPLOYABLE STEERING COLUMN CIRCUITS
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Deployable Steering Column C2318.
- Measure resistance between the deployable steering column C2318-2, circuit RR139 (YE), harness side and C2318-1, circuit CR139 (VT/WH), harness side.
- Is resistance greater than 10,000 ohms?
Yes
INSTALL a new steering column assembly. REFER to Steering Column. GO to S11.
No
GO to S8.
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S8 CHECK THE RCM FOR LOW RESISTANCE
- Disconnect: RCM C310a and C310b.
- Measure resistance between RCM C310a pin 19, component side and C310a pin 20, component side.
- Is resistance greater than 10,000 ohms?
Yes
REPAIR circuits CR139 (VT/WH) and RR139 (YE). GO to S11.
No
GO to S9.
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S9 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 on-demand self test. If not, DTCs will be recorded.
- Connect: Deployable Steering Column C2318.
- Connect: RCM C310a and C310b (if previously disconnected).
- 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 B2984 or B2987 retrieved on-demand during self-test?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to S11.
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 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 S11.
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S10 CHECK FOR AN INTERMITTENT FAULT
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC B2984 or B2987 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 S3.
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 S11.
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S11 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 indicating a fault?
Yes
Do not clear any DTCs until all DTCs 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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