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Home >> Mercury >> 2008 >> Milan Base, 3.0 1, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1722 (Supplemental Restraint System) >> Diagnostic Tests >> Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) >> Pinpoint Tests >> Pinpoint Test Z: DTC B2986 - Deployable Steering Column Circuit Short to Ground >> Pinpoint Test Z: DTC B2986 - Deployable Steering Column Circuit Short To Ground

Pinpoint Test Z: DTC B2986 - Deployable Steering Column Circuit Short To Ground

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
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 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: Always wear eye protection when servicing a vehicle. Failure to follow this instruction may result in serious personal injury.
NOTE: Use the correct probe adapter(s) when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.
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. 
NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.
  1. Z1 CHECK FOR ON-DEMAND AND CONTINUOUS DTCs 
    • Enter the following diagnostic mode on the diagnostic tool: Self Test/ RCM/ Retrieve and Record On-Demand and Continuous Memory DTCs
    • Was on-demand DTC B2986 retrieved? 
    1. 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  Z2.
    2. 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  Z5.
  2. Z2 CHECK THE DEPLOYABLE STEERING COLUMN 
    1. YES  : Go to  Z3.
    2. NO  : REPAIR circuit 2136 (OG) or circuit 2137 (RD/LB). Go to  Z6.
  3. Z3 CHECK CIRCUITS 2136 (OG) AND 2137 (RD/LB) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Disconnect: Deployable Steering Column Restraints System Diagnostic Tool
    • Disconnect: RCM C310a and C310b
      • Fig 1: Measuring Resistance
      GF0013417Courtesy of FORD MOTOR CO.
    • Measure the resistance between deployable steering column C2318-1, circuit 2136 (OG), harness side and ground; and between deployable steering column C2318-2, circuit 2137 (RD/LB), harness side and ground.
    • Are the resistances greater than 10,000 ohms? 
    1. YES  : Go to  Z4.
    2. NO  : REPAIR circuit 2136 (OG) or 2137 (RD/LB). Go to  Z6.
  4. Z4 CONFIRM THE RCM FAULT 
    NOTE: Make sure all restraint system diagnostic tools, sensor electrical connectors and the RCM electrical connectors are connected before carrying out the self test. If not, erroneous DTCs will be recorded.
    • Key in OFF position.
    • Connect: Restraint System Diagnostic Tool 418-F395 to Deployable Steering Column C2318
    • 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 .
    • Enter the following diagnostic mode on the diagnostic tool: Self Test/ RCM/ Retrieve and Record On-Demand and Continuous Memory DTCs
    • Was on-demand DTC B2986 retrieved? 
    1. YES  : INSTALL a new RCM. REFER to Restraints Control Module (RCM) . Go to  Z6.
    2. 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  Z6.
  5. Z5 CHECK FOR AN INTERMITTENT FAULT 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Disconnect: Deployable Steering Column C2318
    • Connect: Restraint System Diagnostic Tool 418-F395 to the Deployable Steering Column C2318
    • Enter the following diagnostic mode on the diagnostic tool: Self Test/ RCM/ Retrieve and Record On-Demand and Continuous Memory DTCs
    • Was on-demand DTC B2986 retrieved? 
    1. 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  Z3.
    2. 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  Z6.
  6. Z6 CHECK FOR ADDITIONAL DTCs 
    • Key in OFF position.
      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 not  prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Self Test/ RCM/ Retrieve and Record On-Demand and Continuous Memory DTCs
    • Enter the following diagnostic mode on the diagnostic tool: Clear all RCM Continuous Memory DTCs
    • Enter the following diagnostic mode on the diagnostic tool: Self Test/RCM
    • Are any RCM DTCs retrieved indicating a fault? 
    1. YES  : Do not clear any DTCs until all DTCs have been resolved. Go to the SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DIAGNOSTIC TROUBLE CODE INDEX  for pinpoint test direction.
    2. NO  : PROVE OUT the SRS. REPAIR is complete. RETURN the vehicle to the customer.
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