Pinpoint Test S: DTCs U0028:08 and U0028:88
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test S: 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 (CAN). If the RCM detects a fault with communications with the ABS module or dedicated CAN circuits, it sets DTC U0028:08 or U0028:88.
The RCM does not request the Instrument Cluster (IC) module to illuminate the air bag warning indicator if either DTC U0028:08 or U0028:88 is set.
- DTC U0028:08 (Vehicle Communication Bus A: Bus Signal / Message Failures) - A fault is indicated when the RCM does not receive dedicated CAN messages from the ABS module for 5 seconds. An open dedicated CAN circuit, incorrectly installed ABS module or loss of power and/or ground to the ABS module can set this DTC. This DTC can also set if the incorrect RCM is installed, such as a non-limousine RCM installed in a vehicle equipped with the limousine package.
- DTC U0028:88 (Vehicle Communication Bus A: Bus Off) - A fault is indicated when the RCM detects the dedicated CAN circuits are shorted to ground, shorted to voltage or shorted to each other.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- RCM
- ABS module
PINPOINT TEST S: 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.
NOTE: 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: Only disconnect or reconnect Supplemental Restraint System (SRS) components 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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S1 RETRIEVE RCM DTCs
- 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
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during self-test.
For DTC U0028:08, GO to S2.
For DTC U0028:88, GO to S6.
No
This is an intermittent fault when present as a Continuous Memory Diagnostic Trouble Code (CMDTC) only. GO to S13.
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S2 CHECK FOR CORRECT RCM
- Enter the following diagnostic mode on the scan tool: Log Viewer.
- Retrieve and record the RCM part number from Log Viewer.
- Check the RCM part number recorded against the part number listed in the Ford Catalog Advantage(TM) or equivalent.
- Is the correct RCM installed in the vehicle?
Yes
GO to S3.
No
INSTALL the correct RCM. REFER to Restraints Control Module (RCM) Service and Repair. GO to S14.
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S3 CHECK FOR CORRECT ABS MODULE
- Retrieve and record the ABS module part number from Log Viewer.
- Check the ABS module part number recorded against the part number listed in the Ford Catalog Advantage(TM) or equivalent.
- Is the correct ABS module installed in the vehicle?
Yes
GO to S4.
No
INSTALL the correct ABS module. REFER to Vehicle Dynamic Systems Service and Repair. GO to S14.
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S4 CHECK THE HS-CAN 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 dedicated CAN communications between the ABS module and RCM.
- Did the Network Test pass (ABS module communicates with the scan tool)?
Yes
GO to S5.
No
REFER to Module Communications Network Testing and Inspection to diagnose the High Speed Controller Area Network (HS-CAN)/ABS module communication concern. GO to S14.
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S5 CHECK THE DEDICATED CAN 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 C135.
- Measure the resistance between the ABS module C135, harness side and the RCM C310B, harness side as indicated in the following chart:
- Are the resistances less than 5 ohms?
Yes
GO to S9.
No
REPAIR circuit VCA23 (BU/WH) or VCA24 (GN/OG).
Refer to Wiring Diagrams for schematic and connector information. Diagrams By Number Go to S14.
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S6 CHECK THE DEDICATED CAN 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 C135.
- 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:
- C135-18, circuit VCA23 (BU/WH), harness side and ground.
- C135-19, circuit VCA24 (GN/OG), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit VCA23 (BU/WH) or VCA24 (GN/OG).
Refer to Wiring Diagrams for schematic and connector information. Diagrams By Number Go to S14.
No
GO to S7.
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S7 CHECK THE DEDICATED CAN CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between ABS module:
- C135-18, circuit VCA23 (BU/WH), harness side and ground.
- C135-19, circuit VCA24 (GN/OG), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to S8.
No
REPAIR circuit VCA23 (BU/WH) or VCA24 (GN/OG).
Refer to Wiring Diagrams for schematic and connector information. Diagrams By Number Go to S14.
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S8 CHECK FOR SHORT BETWEEN THE DEDICATED CAN CIRCUITS
- Measure the resistance between ABS module C135-18, circuit VCA23 (BU/WH), harness side and C135-19, circuit VCA24 (GN/OG), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S9.
No
REPAIR circuits VCA23 (BU/WH) and VCA24 (GN/OG).
Refer to Wiring Diagrams for schematic and connector information. Diagrams By Number Go to S14.
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S9 CHECK THE RCM TERMINATING RESISTOR
- Connect: RCM C310A and C310B.
- Measure the resistance between ABS module C135-18, circuit VCA23 (BU/WH), harness side and C135-19, circuit VCA24 (GN/OG), harness side.
- Is the resistance between 108 and 132 ohms?
Yes
GO to S10.
No
GO to S11.
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S10 CHECK THE ABS MODULE TERMINATING RESISTOR
- Disconnect: RCM C310A and C310B.
- Connect: ABS Module C135.
- Measure the resistance between RCM C310B-20, circuit VCA23 (BU/WH), harness side and C310B-19, circuit VCA24 (GN/OG), harness side.
- Is the resistance between 108 and 132 ohms?
Yes
For DTC U0028:08, GO to S11.
For DTC U0028:88, GO to S12.
No
GO to S12.
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S11 CONFIRM THE RCM FAULT
NOTE: Make sure all restraint system components, sensor electrical connectors and the RCM electrical connectors are connected before carrying out 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 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 Connector Position Assurance (CPA) lever/lock for correct operation. Refer to Restraints Control Module (RCM) Service and Repair.
- inspect ABS module C135 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 Diagrams 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 S14.
No
In the process of diagnosing the fault, the fault condition has become intermittent.
Do not install any new SRS components at this time. Install SRS components only when directed to do so in the pinpoint test. GO to S13.
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S12 CONFIRM THE ABS MODULE FAULT
NOTE: Make sure all restraint system components and the RCM electrical connectors are connected before carrying out 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 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 C135 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 Diagrams 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 ABS Module Removal and Installation in Vehicle Dynamic Systems Service and Repair. GO to S14.
No
In the process of diagnosing the fault, the fault condition has become intermittent.
Do not install any new SRS components at this time. Install SRS components only when directed to do so in the pinpoint test. GO to S13.
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S13 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: ABS Module C135.
- Disconnect: RCM C310B.
- 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 Diagrams 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
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during 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 Diagrams Connector Repair Procedures for schematic and connector information. Diagrams By Number
GO to S14.
No
The fault is not present and cannot be recreated at this time. Do not install any new SRS components at this time. Install SRS components only when directed to do so in the pinpoint test. GO to S14.
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S14 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 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 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. Diagnostic Trouble Code Tests and Associated Procedures
No
CLEAR all CMDTCs. PROVE OUT the SRS. The repair is complete. RETURN the vehicle to the customer.
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