U1105

U1105-CAN B SIGNAL MISSING

U1105-CAN B Signal Missing:

WHEN MONITORED
Continuously

SET CONDITION
When the CAN B Bus messages are not received within 2 seconds.

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

DIAGNOSTIC TEST

1. CHECK FOR ACTIVE DTCs
With the scan tool, read the active DTC's.
Cycle the ignition switch from off to on atleast 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 FOR U0019 DTC
With the scan tool, read Front Control Module active DTC's

Q: Does the scan tool display U0019 CAN B BUS - ACTIVE?

YES: Perform the U0019 diagnostic procedure.
NO: Go To 3

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




Turn the ignition off.
Disconnect the Front Control Module C1 connector.
Turn the ignition on.
Measure the voltage of the (D55) CAN B Bus (+) circuit.

Q: Is any voltage present on this circuit?

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 voltage of the (D54) CAN B Bus (-) circuit.

Q: Is any voltage present on this circuit?

YES: Replace the Front Control Module. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (D54) CAN B Bus (-) circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test