Part 1
Communications Network
Pinpoint Test U: 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 Electrical Diagrams.
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) module (if equipped)
- Dual Climate Controlled Seat Module (DCSM) (if equipped)
- Driver Seat Module (DSM) (if equipped)
- Global Positioning System Module (GPSM)
- 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)
- Satellite Digital Audio Receiver System (SDARS) module (if equipped)
- Smart Junction Box (SJB)
- Data Link Connector (DLC)
PINPOINT TEST U : NO MS-CAN (Medium Speed Controller Area Network) 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.
U1 CHECK THE DLC (Data Link Connector) PINS FOR DAMAGE
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
- Ignition OFF.
- Disconnect the scan tool cable from the Data Link Connector (DLC).
- Inspect DLC (Data Link Connector) pins 3 and 11 for damage.
Are DLC (Data Link Connector) pins 3 and 11 OK?
Yes
GO to U2.
No
REPAIR the DLC (Data Link Connector) as necessary. CLEAR the DTCs. REPEAT the network test with the scan tool.
U2 CHECK THE MS-CAN (Medium Speed Controller Area Network) TERMINATION RESISTANCE
- Disconnect: Negative Battery Cable.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance between 54 and 66 ohms?
Yes
GO to U5.
No
GO to U3.
U3 CHECK THE MS-CAN (Medium Speed Controller Area Network) TERMINATION RESISTOR
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance between 108 and 132 ohms?
Yes
GO to U7.
No
GO to U4.
U4 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U8.
No
GO to U7.
U5 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TO GROUND
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side and ground.
Are the resistances greater than 1,000 ohms?
Yes
GO to U6.
No
GO to U33.
U6 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TO VOLTAGE
- Connect the negative battery cable.
- Ignition ON.
- Measure the voltage between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side and ground.
Is the voltage greater than 6 volts?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.
No
VERIFY all module fuses are OK. If OK, REPEAT the network test with the scan tool.
U7 CHECK THE MS-CAN (Medium Speed Controller Area Network) CIRCUITS BETWEEN THE SJB (Smart Junction Box) AND THE DLC (Data Link Connector) FOR AN OPEN
- Disconnect: SJB (Smart Junction Box) C2280B.
- Measure the resistance between the SJB (Smart Junction Box) C2280B-37, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side.
- Measure the resistance between the SJB (Smart Junction Box) C2280B-38, circuit VDB07 (VT/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Are the resistances less than 5 ohms?
Yes
VERIFY all module fuses are OK. If OK, CONNECT the SJB (Smart Junction Box). CONNECT the negative battery cable. REPEAT the network test with the scan tool.
No
REPAIR the circuit in question. CONNECT the SJB (Smart Junction Box). CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
U8 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE SJB (Smart Junction Box) DISCONNECTED
- Disconnect: SJB (Smart Junction Box) C2280B.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U9.
No
CONNECT the negative battery cable. GO to U58.
U9 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE IC (Instrument Cluster) DISCONNECTED
- Disconnect: IC (Instrument Cluster) C220.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U10.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U59.
U10 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE ACM (Audio Control Module) DISCONNECTED
- Disconnect: ACM (Audio Control Module) C240A.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U11.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U60.
U11 VERIFY VEHICLE EQUIPMENT - AUDIO DSP (Digital Signal Processing) MODULE
- Inspect the vehicle for an audio Digital Signal Processing (DSP) module.
Is the vehicle equipped with an audio DSP (Digital Signal Processing) module?
Yes
GO to U12.
No
GO to U13.
U12 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE AUDIO DSP (Digital Signal Processing) MODULE DISCONNECTED
- Disconnect: Audio DSP (Digital Signal Processing) Module C2364C.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U13.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U61.
U13 VERIFY VEHICLE EQUIPMENT - HVAC MODULE
- Inspect the vehicle for an HVAC module.
Is the vehicle equipped with an HVAC module?
Yes
GO to U14.
No
GO to U15.
U14 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE HVAC MODULE DISCONNECTED
- Disconnect: HVAC Module C228A (EATC (Electronic Automatic Temperature Control)) or C2357A (EMTC (Electronic Manual Temperature Control)).
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U15.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U62.
U15 VERIFY VEHICLE EQUIPMENT - APIM (Accessory Protocol Interface Module)
- Inspect the vehicle for an APIM (Accessory Protocol Interface Module).
Is the vehicle equipped with an APIM (Accessory Protocol Interface Module)?
Yes
GO to U16.
No
GO to U17.
U16 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE APIM (Accessory Protocol Interface Module) DISCONNECTED
- Disconnect: APIM (Accessory Protocol Interface Module) C3342.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U17.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U63.
U17 VERIFY VEHICLE EQUIPMENT - AUDIO RCU (Rear Control Unit) MODULE
- Inspect the vehicle for an audio Rear Control Unit (RCU) module.
Is the vehicle equipped with an audio RCU (Rear Control Unit) module?
Yes
GO to U18.
No
GO to U19.
U18 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE AUDIO RCU (Rear Control Unit) MODULE DISCONNECTED
- Disconnect: Audio RCU (Rear Control Unit) module C3077.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U19.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U64.
U19 VERIFY VEHICLE EQUIPMENT - DSM (Driver Seat Module)
- Inspect the vehicle for a Driver Seat Module (DSM).
Is the vehicle equipped with a DSM (Driver Seat Module)?
Yes
GO to U20.
No
GO to U21.
U20 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE DSM (Driver Seat Module) DISCONNECTED
- Disconnect: Driver Seat Module C341D.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U21.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U65.
U21 VERIFY VEHICLE EQUIPMENT - DCSM (Dual Climate Controlled Seat Module)
- Inspect the vehicle for a Dual Climate Controlled Seat Module (DCSM).
Is the vehicle equipped with a DCSM (Dual Climate Controlled Seat Module)?
Yes
GO to U22.
No
GO to U23.
U22 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE DCSM (Dual Climate Controlled Seat Module) DISCONNECTED
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U23.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U66.
U23 VERIFY VEHICLE EQUIPMENT - SDARS (Satellite Digital Audio Receiver System) MODULE
- Inspect the vehicle for a Satellite Digital Audio Receiver System (SDARS) module.
Is the vehicle equipped with a SDARS (Satellite Digital Audio Receiver System) module?
Yes
GO to U24.
No
GO to U25.
U24 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE SDARS (Satellite Digital Audio Receiver System) MODULE DISCONNECTED
- Disconnect: SDARS (Satellite Digital Audio Receiver System) Module C3290.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U25.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U67.
U25 VERIFY VEHICLE EQUIPMENT - PRB (Power Running Board) MODULE
- Inspect the vehicle for a Power Running Board (PRB) module.
Is the vehicle equipped with a PRB (Power Running Board) module?
Yes
GO to U26.
No
GO to U27.
U26 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE PRB (Power Running Board) MODULE DISCONNECTED
- Disconnect: PRB (Power Running Board) Module C3313B.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U27.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U68.
U27 VERIFY VEHICLE EQUIPMENT - PAM (Parking Aid Module)
- Inspect the vehicle for a Parking Aid Module (PAM).
Is the vehicle equipped with a PAM (Parking Aid Module)?
Yes
GO to U28.
No
GO to U29.
U28 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE PAM (Parking Aid Module) DISCONNECTED
- Disconnect: PAM (Parking Aid Module) C4226 (Expedition) or C4014A (Navigator).
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U29.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U69.
U29 VERIFY VEHICLE EQUIPMENT - GPSM (Global Positioning System Module)
- Inspect the vehicle for a GPSM (Global Positioning System Module).
Is the vehicle equipped with a GPSM (Global Positioning System Module)?
Yes
GO to U30.
No
GO to U31.
U30 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE GPSM (Global Positioning System Module) DISCONNECTED
- Disconnect: GPSM (Global Positioning System Module) C2398.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) C251-11, circuit VDB07 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to U31.
No
CONNECT all modules. CONNECT the negative battery cable. GO to U71.
U31 VERIFY VEHICLE EQUIPMENT - LTM (Liftgate/Trunk Module)
- Inspect the vehicle for a Liftgate/Trunk Module (LTM).
Is the vehicle equipped with an LTM (Liftgate/Trunk Module)?
Yes
GO to U32.
No
REPAIR the circuits. CONNECT all modules. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
U32 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TOGETHER WITH THE LTM (Liftgate/Trunk Module) DISCONNECTED
- Disconnect: LTM (Liftgate/Trunk Module) C4174B.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and the DLC (Data Link Connector) 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 U70.
U33 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TO GROUND WITH THE SJB (Smart Junction Box) DISCONNECTED
- Disconnect: SJB (Smart Junction Box) C2280B.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC (Data Link Connector) 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 U58.
No
GO to U34.
U34 CHECK THE MS-CAN (Medium Speed Controller Area Network) (+) AND MS-CAN (Medium Speed Controller Area Network) (-) CIRCUITS FOR A SHORT TO GROUND WITH THE IC (Instrument Cluster) DISCONNECTED
- Disconnect: IC (Instrument Cluster) C220.
- Measure the resistance between the DLC (Data Link Connector) C251-3, circuit VDB06 (GY/OG), harness side and ground; and between the DLC (Data Link Connector) 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 U59.
No
GO to U35.