Diagnostic Routine I

Diagnostic Routine I

Diagnostic Overview

The Body Control Module (BCM) Does Not Respond To The Scan Tool

Refer to Wiring Diagram Set 13 for schematic and connector information Electrical Diagrams.

Refer to Wiring Diagram Set 14 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

The BCM (Body Control Module) communicates with the scan tool through the HS-CAN (High Speed Controller Area Network) and communicates with the other modules through the MS-CAN (Medium Speed Controller Area Network).

Visual Inspection and Diagnostic Pre-checks

Verify BCM (Battery Control Module) MEGA fuses 4 (50A) and 9 (50A) are OK.

Pinpoint Test

1. CHECK POWER TO THE BCM (Body Control Module)

1. Ignition ON.

2. Disconnect: BCM (Body Control Module) C2280G.

3. Measure:





Is the voltage greater than 11 volts?






2. CHECK THE BCM (Body Control Module) GROUND CIRCUITS FOR AN OPEN

1. Disconnect: BCM (Body Control Module) C2280E and C2280A.

2. Measure:





3. Measure:





Are the resistances less than 3 ohms?






3. CHECK THE HS-CAN (High Speed Controller Area Network) TERMINATION RESISTANCE

1. Ignition OFF.

2. Disconnect the scan tool cable from the DLC (Data Link Connector).

3. Measure:





Is the resistance between 54 and 66 ohms?






4. CHECK THE MS-CAN (Medium Speed Controller Area Network) TERMINATION RESISTANCE

1. Connect: BCM (Body Control Module) C2280A.

2. Measure:





Is the resistance between 54 and 66 ohms?






5. CHECK THE MS-CAN (Medium Speed Controller Area Network) TERMINATION RESISTANCE WITH THE IPC (Instrument Panel Cluster) DISCONNECTED

1. Disconnect: IPC (Instrument Panel Cluster).

2. Measure:





Is the resistance between 108 and 132 ohms?






6. CHECK THE MS-CAN (Medium Speed Controller Area Network) CIRCUITS BETWEEN THE BCM (Body Control Module) AND THE DLC (Data Link Connector) FOR AN OPEN

1. Disconnect: BCM (Body Control Module) C2280A.

2. Measure:





Are the resistances less than 3 ohms?






7. CHECK THE MS-CAN (Medium Speed Controller Area Network) CIRCUITS FOR A SHORT TO POWER

1. Connect: BCM (Body Control Module) C2280A.

2. Ignition ON.

3. Measure:





Is the voltage greater than 3 volts on either circuit?






8. CHECK THE MS-CAN (Medium Speed Controller Area Network) CIRCUITS FOR A SHORT TO GROUND

1. Ignition OFF.

2. Measure:





Are the resistances greater than 10,000 ohms?






9. CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS BETWEEN THE BCM (Body Control Module) AND THE DLC (Data Link Connector) FOR AN OPEN

1. Disconnect: BCM (Body Control Module) C2280C.

2. Measure:





Are the resistances less than 3 ohms?






10. CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS FOR A SHORT TO POWER

1. Connect: BCM (Body Control Module) C2280C.

2. Ignition ON.

3. Measure:





Is the voltage greater than 6 volts on either circuit?






11. CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS FOR A SHORT TO GROUND

1. Measure:





Are the resistances greater than 10,000 ohms?






12. CHECK FOR CORRECT BCM (Body Control Module) OPERATION

1. Ignition OFF.

2. Disconnect and inspect the BCM (Body Control Module) connectors.

3. Repair:

- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary

4. Reconnect the BCM (Body Control Module) connectors. Make sure they seat and latch correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?