Pinpoint Test L: DTCs U0028:08 and U0028:88
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test L: DTCs U0028:08 and U0028:88
Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
The Restraints Control Module (RCM) supplies the stability/traction control system with the yaw rate, roll rate, lateral and longitudinal accelerometer over a dedicated Controller Area Network 2 (CAN2) bus. If the RCM detects a fault with comminutions with the ABS module or CAN2 bus circuits, it will set DTC U0028:08 or U0028:88.
The RCM does not request the Instrument Panel Cluster (IPC) module to illuminate the air bag warning indicator if either DTC U0028:08 or U0028:88 is set. The air bag warning indicator will remain off if either of these DTCs are set.
- DTC U0028:08 (Vehicle Communication Bus A: Bus Signal / Message Failures) - When the RCM does not receive CAN2 bus messages from the ABS module for 5 seconds, a fault will be indicated. An open CAN2 circuit, incorrect installed ABS module or loss of power and/or ground to the ABS module can set this DTC.
- DTC U0028:88 (Vehicle Communication Bus A: Bus Off) - When the RCM detects the CAN2 circuits are shorted to ground, shorted to voltage or shorted to each other, a fault will be indicated.
The ABS module may set similar DTCs, U0151 (Lost Communication With Restraints Control Module) and U0452 (Invalid Data Received From Restraints Control Module).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- RCM
- ABS module
PINPOINT TEST L: DTCs U0028:08 and U0028:88
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 disassemble or tamper with safety belt buckle/retractor pretensioners or adaptive load limiting retractors or probe the electrical connectors. 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: 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: Always make sure the correct SRS component is being installed. Parts released for other vehicles may not be compatible even if they appear physically similar. Check the part number listed in the Ford Catalog Advantage(TM) or equivalent to make sure the correct component is being installed. If an incorrect SRS component is installed, DTCs may set.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
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L1 RETRIEVE RCM DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC B0028:08 or B0028:88 retrieved on-demand during self-test?
Yes
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during self-test.
For DTC U0028:08, GO to L2.
For DTC U0028:88, GO to L6.
No
This is an intermittent fault when present as a CMDTC only. GO to L13.
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L2 CHECK FOR CORRECT RCM
- 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.
- Gain access to the RCM and check the part number on the RCM against the part number listed in the Ford Catalog Advantage(TM) or equivalent. Refer to Restraints Control Module (RCM) Service and Repair.
- Does the part number match?
Yes
GO to L3.
No
INSTALL the correct RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to L14.
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L3 CHECK FOR CORRECT ABS MODULE
- NOTE: This vehicle has the option of Roll Stability Control (RSC(R)), verify the correct option content of this vehicle.
- Gain access the ABS module and check the part number on the ABS module against the part number listed in the Ford Catalog Advantage(TM) or equivalent. Refer to the Removal and Installation procedure in Vehicle Dynamic Systems Service and Repair.
- Does the part number match?
Yes
GO to L4.
No
INSTALL the correct ABS module. REFER to the Removal and Installation procedure in Vehicle Dynamic Systems Service and Repair. GO to L14.
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L4 CHECK THE HS-CAN NETWORK COMMUNICATIONS (ABS MODULE COMMUNICATIONS)
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Network Test.
- NOTE: The Network Test does not test the CAN2 communications between the ABS module and RCM. The CAN2 is a dedicated communication network between the 2 modules.
- Did the Network Test pass (ABS module communicate with the scan tool)?
Yes
GO to L5.
No
REFER to Module Communications Network Testing and Inspection to diagnose the HS-CAN/ABS module communication concern. GO to L14.
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L5 CHECK THE CAN2 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.
- Disconnect: ABS Module C155.
- Measure the resistance between the ABS module C155, harness side and the RCM C310B, harness side as indicated in the following chart:
- Are the resistances less 5 ohms?
Yes
GO to L9.
No
REPAIR circuit VDB05 (WH) or VDB04 (WH/BU). GO to L14.
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L6 CHECK THE CAN2 CIRCUITS FOR A SHORT TO VOLTAGE
- 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: ABS Module C155.
- Repower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure the voltage between ABS module:
- C155-20, circuit VDB04 (WH/BU), harness side and ground.
- C155-34, circuit VDB05 (WH), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR circuit VDB04 (WH/BU) or VDB05 (WH). GO to L14.
No
GO to L7.
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L7 CHECK THE CAN2 CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between ABS module:
- C155-20, circuit VDB04 (WH/BU), harness side and ground.
- C155-34, circuit VDB05 (WH), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to L8.
No
REPAIR circuit VDB04 (WH/BU) or VDB05 (WH). GO to L14.
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L8 CHECK FOR SHORT BETWEEN CAN2 CIRCUITS
- Measure the resistance between ABS module C155-20, circuit VDB04 (WH/BU), harness side and ABS module C155-34, circuit VDB05 (WH), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to L9.
No
REPAIR circuits VDB04 (WH/BU) and VDB05 (WH). GO to L14.
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L9 CHECK THE RCM TERMINATING RESISTOR
- Connect: RCM C310B.
- Measure the resistance between ABS module C155-20, circuit VDB04 (WH/BU), harness side and ABS module C155-34, circuit VDB05 (WH), harness side.
- Is the resistance between 108 and 132 ohms?
Yes
GO to L10.
No
GO to L11.
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L10 CHECK THE ABS MODULE TERMINATING RESISTOR
- Disconnect: RCM C310B.
- Connect: ABS Module C155.
- Measure the resistance between RCM C310B-20, circuit VDB04 (WH/BU), harness side and C310B-19, circuit VDB05 (WH), harness side.
- Is the resistance between 108 and 132 ohms?
Yes
For DTC U0028:08, GO to L11.
For DTC U0028:88, GO to L12.
No
GO to L12.
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L11 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, DTCs will be recorded.
- If previously directed to repower the SRS, depower the SRS. Refer to SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Prior to reconnecting any previously disconnected SRS component:
- inspect connector(s) (including any in-line connectors) for pushed out, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- inspect RCM C310A and C310B CPA lever/lock for correct operation. Refer to Restraints Control Module (RCM) Service and Repair.
- inspect ABS module C155 for dirt, corrosion, water intrusion, pushed out, loose or spread terminals and loose or frayed wire connections at terminals.
- repair any concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
- Connect: All Previously Disconnected Component(s)/Connector(s).
- 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.
- Was DTC U0028:08 retrieved on-demand during self-test?
Yes
INSTALL a new RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to L14.
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. 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. GO to L13.
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L12 CONFIRM THE ABS MODULE 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, DTCs will be recorded.
- If previously directed to repower the SRS, depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering.
- Prior to reconnecting any previously disconnected SRS component:
- inspect connector(s) (including any in-line connectors) for pushed out, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- inspect RCM C310A and C310B CPA lever/lock for correct operation. Refer to Restraints Control Module (RCM) Service and Repair.
- inspect ABS module C155 for dirt, corrosion, water intrusion, pushed out, loose or spread terminals and loose or frayed wire connections at terminals.
- repair any concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
- Connect: All Previously Disconnected Component(s)/Connector(s).
- 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.
- Was DTC U0028:88 retrieved on-demand during self-test?
Yes
INSTALL a new ABS module. REFER to the Removal and Installation procedure in Vehicle Dynamic Systems Service and Repair. GO to L14.
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. 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. GO to L13.
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L13 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 RCM C310B and ABS module C155:
- inspect connector(s) (including any in-line connectors) for corrosion, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- repair any concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
- Connect: All Previously Disconnected Component(s)/Connector(s).
- 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.
- Was DTC U0028:08 or U0028:88 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 on-demand during the self-test.
CHECK for causes of the intermittent fault in the areas previously worked in, particularly the pins and terminals of any electrical connector that were disconnected. REPAIR any intermittent wiring, terminal or connector concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
GO to L14.
No
The fault is not present and cannot be recreated at this time. 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. GO to L14.
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L14 CHECK FOR ADDITIONAL RCM AND ABS MODULE 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 not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module.
- Were any DTCs retrieved on-demand from the RCM or ABS module during self-test?
Yes
Do not clear any DTCs until all DTCs have been resolved. GO to the appropriate DTC Chart and/or Vehicle Dynamic Systems Testing and Inspection for pinpoint test direction.
No
CLEAR all CMDTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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