Vehicle Theft Security System

U0019-CAN B BUS

For a complete wiring diagram refer to Wiring Section.

U0019-CAN B Bus:

WHEN MONITORED
Continuously

SET CONDITION
Whenever the CAN B Bus (+) or CAN B Bus (-) circuit is open, shorted to voltage or shorted to ground.

POSSIBLE CAUSES
- CAN B BUS DTC's in front control module
- (D55) CAN B BUS (+) circuit open
- (D54) CAN B BUS (-) circuit open
- SKREEM

Diagnostic Test

1. CHECK FOR ACTIVE DTC's
With the scan tool, read the active DTC's.
Cycle the ignition switch from off to on at least 5 times, leaving the ignition on for a minimum of 90 seconds per cycle.
With the scan tool, read the active DTC's.

Q: Does the scan tool display this DTC as active?

YES: Go To 2
NO: If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.

2. CHECK FRONT CONTROL MODULE DTC's

With the scan tool, read Front Control Module active DTC's

Q: Does the scan tool display any CAN B BUS DTC's - ACTIVE?

YES: Refer to Body Control Module - DIAGNOSIS AND TESTING.
NO: Go To 3

3. (D55) CAN B BUS (+) CIRCUIT OPEN




Turn the ignition off.
Disconnect the negative battery cable.
Disconnect the SKREEM connector.
Disconnect the Front Control Module C1 connector.
Measure the resistance of the (D55) CAN B Bus (+) circuit between the Front Control Module C1 harness connector and the SKREEM harness connector.

Q: Is the resistance below 2.0 ohms?

YES: Go To 4
NO: Repair the (D55) CAN B Bus (+) circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4. (D54) CAN B BUS (-) CIRCUIT OPEN




Measure the resistance of the (D54) CAN B Bus (-) circuit between the Front Control Module C1 harness connector and the SKREEM harness connector.

Q: Is the resistance below 2.0 ohms?

YES: Replace the SKREEM. Perform BODY VERIFICATION TEST - VER 1.
NO: Repair the (D54) CAN B Bus (-) circuit for an open. Perform BODY VERIFICATION TEST - VER 1.