V25-V48
Communications Network
Pinpoint Tests
Pinpoint Test V: No Medium Speed Controller Area Network (MS-CAN) Communication, All Modules Are Not Responding
Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. Diagrams By Number
Normal Operation
The Medium Speed Controller Area Network (MS-CAN) uses an unshielded twisted pair cable, circuits VDB06 (GY/OG) and VDB07 (VT/OG) provide the network connection to all modules on the network.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Audio Control Module (ACM)
- Accessory Protocol Interface Module (APIM)
- Audio Digital Signal Processing (DSP) module (if equipped)
- Audio Rear Control Unit (RCU) (if equipped)
- Dual Climate Controlled Seat Module (DCSM) (if equipped)
- Driver Seat Module (DSM) (if equipped)
- HVAC module (if equipped)
- Instrument Cluster (IC)
- Liftgate/Trunk Module (LTM) (if equipped)
- Parking Aid Module (PAM) (if equipped)
- Power Running Board (PRB) module (if equipped)
- Rear Entertainment Module (RETM) (if equipped)
- Satellite Digital Audio Receiver System (SDARS) module (if equipped)
- Smart Junction Box (SJB)
- Data Link Connector (DLC)
PINPOINT TEST V: NO MS-CAN COMMUNICATION, ALL MODULES ARE NOT RESPONDING
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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V25 VERIFY VEHICLE EQUIPMENT - SDARS MODULE
- Inspect the vehicle for a Satellite Digital Audio Receiver System (SDARS) module.
- Is the vehicle equipped with a SDARS module?
Yes
GO to V26.
No
GO to V27.
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V26 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE SDARS MODULE DISCONNECTED
- Disconnect: SDARS Module C3290.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to V27.
No
CONNECT all modules. CONNECT the negative battery cable. GO to V68.
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V27 VERIFY VEHICLE EQUIPMENT - PRB MODULE
- Inspect the vehicle for a Power Running Board (PRB) module.
- Is the vehicle equipped with a PRB module?
Yes
GO to V28.
No
GO to V29.
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V28 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE PRB MODULE DISCONNECTED
- Disconnect: PRB Module C3313b.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to V29.
No
CONNECT all modules. CONNECT the negative battery cable. GO to V69.
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V29 VERIFY VEHICLE EQUIPMENT - PAM
- Inspect the vehicle for a Parking Aid Module (PAM).
- Is the vehicle equipped with a PAM?
Yes
GO to V30.
No
GO to V31.
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V30 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE PAM DISCONNECTED
- Disconnect: PAM C4226 (Expedition) or C4014a (Navigator).
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to V31.
No
CONNECT all modules. CONNECT the negative battery cable. GO to V70.
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V31 VERIFY VEHICLE EQUIPMENT - LTM
- Inspect the vehicle for a Liftgate/Trunk Module (LTM).
- Is the vehicle equipped with an LTM?
Yes
GO to V32.
No
REPAIR the circuits. CONNECT all modules. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
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V32 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE LTM DISCONNECTED
- Disconnect: LTM C4174b.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
REPAIR the circuits. CONNECT all modules. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
No
CONNECT all modules. CONNECT the negative battery cable. GO to V71.
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V33 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE SJB DISCONNECTED
- Disconnect: SJB C2280b.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT the negative battery cable. GO to V58.
No
GO to V34.
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V34 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE IC DISCONNECTED
- Disconnect: IC C220.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V59.
No
GO to V35.
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V35 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE ACM DISCONNECTED
- Disconnect: ACM C240b.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V60.
No
GO to V36.
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V36 VERIFY VEHICLE EQUIPMENT - AUDIO DSP MODULE
- Inspect the vehicle for an audio DSP module.
- Is the vehicle equipped with an audio DSP module?
Yes
GO to V37.
No
GO to V38.
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V37 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE AUDIO DSP MODULE DISCONNECTED
- Disconnect: Audio DSP Module C2364c.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V61.
No
GO to V38.
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V38 VERIFY VEHICLE EQUIPMENT - HVAC MODULE
- Inspect the vehicle for an HVAC module.
- Is the vehicle equipped with an HVAC module?
Yes
GO to V39.
No
GO to V40.
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V39 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE HVAC MODULE DISCONNECTED
- Disconnect: HVAC Module C228a (EATC) or C2357a (EMTC).
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V62.
No
GO to V42.
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V40 VERIFY VEHICLE EQUIPMENT - APIM
- Inspect the vehicle for an Accessory Protocol Interface Module (APIM).
- Is the vehicle equipped with an APIM?
Yes
GO to V41.
No
GO to V42.
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V41 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE APIM DISCONNECTED
- Disconnect: APIM C3342.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V63.
No
GO to V42.
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V42 VERIFY VEHICLE EQUIPMENT - AUDIO RCU
- Inspect the vehicle for an audio Rear Control Unit (RCU).
- Is the vehicle equipped with an audio RCU?
Yes
GO to V43.
No
GO to V44.
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V43 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE AUDIO RCU DISCONNECTED
- Disconnect: Audio RCU C3077.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V64.
No
GO to V44.
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V44 VERIFY VEHICLE EQUIPMENT - RETM
- Inspect the vehicle for a Rear Entertainment Module (RETM).
- Is the vehicle equipped with an RETM?
Yes
GO to V45.
No
GO to V46.
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V45 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE RETM DISCONNECTED
- Disconnect: RETM C949.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V65.
No
GO to V46.
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V46 VERIFY VEHICLE EQUIPMENT - DSM
- Inspect the vehicle for a Driver Seat Module (DSM).
- Is the vehicle equipped with a DSM?
Yes
GO to V47.
No
GO to V48.
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V47 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE DSM DISCONNECTED
- Disconnect: DSM C341d.
- Measure the resistance between the DLC C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC C251-11, circuit VDB07 (VT/OG), harness side and ground.
- Are the resistances greater than 1,000 ohms?
Yes
CONNECT all modules. CONNECT the negative battery cable. GO to V66.
No
GO to V48.
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V48 VERIFY VEHICLE EQUIPMENT - DCSM
- Inspect the vehicle for a Dual Climate Controlled Seat Module (DCSM).
- Is the vehicle equipped with a DCSM?
Yes
GO to V49.
No
GO to V50.
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