Operation CHARM: Car repair manuals for everyone.

Y19-Y35




Communications Network

Pinpoint Tests

Pinpoint Test Y: 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
- Accessory Protocol Interface Module (APIM)
- Audio Control Module (ACM)
- Audio Digital Signal Processing (DSP) module
- Driver Door Module (DDM)
- Driver Seat Module (DSM)
- Dual Climate Controlled Seat Module (DCSM)
- Front Controls Interface Module (FCIM)
- Front Display Interface Module (FDIM)
- Headlamp Control Module 2 (HCM-2)
- HVAC module
- Instrument Panel Cluster (IPC)
- Parking Aid Module (PAM)
- Remote Function Actuator (RFA) module
- Smart Junction Box (SJB)



PINPOINT TEST Y: 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: 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: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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Y19 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE DCSM DISCONNECTED


- Disconnect: Dual Climate Controlled Seat Module (DCSM) C3265c.
- 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
If the vehicle is equipped with a navigation Audio Control Module (ACM), GO to Y20.

If the vehicle is not equipped with a navigation ACM, GO to Y21.

No
CONNECT the battery ground cable. GO to Y47.

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Y20 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE FDIM DISCONNECTED


- Disconnect: Front Display Interface Module (FDIM) C2123.
- 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 Y21.

No
CONNECT the battery ground cable. GO to Y48.

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Y21 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE HVAC MODULE DISCONNECTED


- Disconnect: HVAC Module C228a (Without Navigation ACM) or C2356a (With Navigation ACM).
- 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 Y22.

No
CONNECT the battery ground cable. GO to Y49.

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Y22 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE FCIM DISCONNECTED


- Disconnect: Front Controls Interface Module (FCIM) C2402 (Without Navigation ACM) or C2403 (With Navigation ACM).
- 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
If the vehicle is equipped with an Accessory Protocol Interface Module (APIM), GO to Y23.

If the vehicle is not equipped with an APIM, GO to Y24.

No
CONNECT the battery ground cable. GO to Y50.

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Y23 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE APIM DISCONNECTED


- Disconnect: APIM C3342.
- 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 Y24.

No
CONNECT the battery ground cable. GO to Y51.

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Y24 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TOGETHER WITH THE IPC DISCONNECTED


- Disconnect: IPC C220.
- 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 circuit. CONNECT all modules. CONNECT the battery ground cable. CLEAR the DTCs. REPEAT the network test with the scan tool.

No
CONNECT the battery ground cable. GO to Y52.

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Y25 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 battery ground cable. GO to Y39.

No
GO to Y26.

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Y26 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE PAM DISCONNECTED


- Disconnect: Parking Aid Module (PAM) C4014 (Rear) or C4226a (Front and Rear).
- 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 battery ground cable. GO to Y40.

No
GO to Y27.

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Y27 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE ACM DISCONNECTED


- Disconnect: Audio Control Module (ACM) C240b (Without Navigation) or C2253b (With Navigation).
- 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 battery ground cable. GO to Y41.

No
If the vehicle is equipped with an audio Digital Signal Processing (DSP) module, GO to Y28.

If the vehicle is not equipped with an audio DSP module, GO to Y29.

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Y28 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE AUDIO DSP MODULE DISCONNECTED


- Disconnect: Audio DSP Module C4326a.
- 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 battery ground cable. GO to Y42.

No
GO to Y29.

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Y29 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE DDM DISCONNECTED


- Disconnect: Driver Door Module (DDM) C501a.
- 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 battery ground cable. GO to Y43.

No
If the vehicle is equipped with a Remote Function Actuator (RFA) module, GO to Y30.

If the vehicle is not equipped with a RFA module, GO to Y31.

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Y30 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE RFA MODULE DISCONNECTED


- Disconnect: RFA Module C2153d.
- 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 battery ground cable.GO to Y44.

No
GO to Y31.

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Y31 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE DSM DISCONNECTED


- Disconnect: Driver Seat Module (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 the battery ground cable. GO to Y45.

No
If the vehicle is equipped with a Headlamp Control Module 2 (HCM-2), GO to Y32.

If the vehicle is not equipped with a HCM-2, GO to Y33.

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Y32 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE HCM-2DISCONNECTED


- Disconnect: Inline HCM-2 C913.
- 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 battery ground cable.GO to Y46.

No
GO to Y33.

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Y33 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE DCSM DISCONNECTED


- Disconnect: Dual Climate Controlled Seat Module (DCSM) C3265c.
- 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 battery ground cable. GO to Y47.

No
If the vehicle is equipped with a navigation Audio Control Module (ACM), GO to Y34.

If the vehicle is not equipped with a navigation ACM, GO to Y35.

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Y34 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE FDIM DISCONNECTED


- Disconnect: Front Display Interface Module (FDIM) C2123.
- 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 battery ground cable. GO to Y48.

No
GO to Y35.

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Y35 CHECK THE MS-CAN (+) AND MS-CAN (-) CIRCUITS FOR A SHORT TO GROUND WITH THE HVAC MODULE DISCONNECTED


- Disconnect: HVAC Module C228a (Without Navigation ACM) or C2356a (With Navigation ACM).
- 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 battery ground cable. GO to Y49.

No
GO to Y36.

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