Pinpoint Test F: The Occupant Classification System Module (OCSM) Does Not Communicate With The Scan Tool

Communications Network

Pinpoint Tests

Pinpoint Test F: The Occupant Classification System Module (OCSM) Does Not Communicate With the Scan Tool

Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. Diagrams By Number

Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number

Normal Operation

The Occupant Classification System Module (OCSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN). Circuits VDB06 (GY/OG) (MS-CAN +) and VDB07 (VT/OG) (MS-CAN -) provide the network connection to the OCSM. The OCSM shares the MS-CAN with the Smart Junction Box (SJB), the Accessory Protocol Interface Module (APIM), the Driver Seat Module (DSM), the HVAC module, the Rear Entertainment Module (RETM), the Satellite Digital Audio Receiver System (SDARS) module, and the Instrument Cluster (IC). Voltage for the OCSM is provided by circuit CBP46 (WH/BU). Circuit GD133 (BK) provides ground.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- OCSM



PINPOINT TEST F: THE OCSM DOES NOT COMMUNICATE WITH THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

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F1 CHECK THE OCSM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN


- Ignition OFF.
- Disconnect: OCSM C3285.
- Ignition ON.
- Measure the voltage between the OCSM C3285-1, circuit CBP46 (WH/BU), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to F2.

No
VERIFY the SJB fuse 46 (7.5A) is OK. If OK, REPAIR the circuit. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the short circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.

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F2 CHECK THE OCSM GROUND CIRCUIT FOR AN OPEN


- Ignition OFF.
- Measure the resistance between the OCSM C3285-14, circuit GD133 (BK), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to F3.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.

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F3 CHECK THE HS-CAN CIRCUITS BETWEEN THE OCSM AND THE DATA LINK CONNECTOR (DLC) FOR AN OPEN


- Measure the resistance between the OCSM C3285-18, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.




- Measure the resistance between the OCSM C3285-9, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.




- Are the resistances less than 5 ohms?

Yes
GO to F4.

No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool.

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F4 CHECK FOR CORRECT OCSM OPERATION


- Disconnect the OCSM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the OCSM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new OCSM. REPEAT the network test with the scan tool.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the network test with the scan tool.

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