U0019-CAN B BUS
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
Continuously.
- Set Condition:
If the Can B Bus (+) or B Bus (–) circuit is open, shorted to voltage, or shorted to ground.
| Possible Causes |
| CAN B BUS DTCs IN FRONT CONTROL MODULE |
| (D55) CAN B BUS (+) CIRCUIT OPEN |
| (D54) CAN B BUS (–) CIRCUIT OPEN |
| ELECTRONIC OVERHEAD MODULE |
Diagnostic Test
1. CHECK FOR ACTIVE DTC U0019–CAN B BUSTurn the ignition on.
With the scan tool, record and erase any Electronic Overhead Module DTCs.
Turn the ignition off, wait 30 seconds then turn the ignition on.
With the scan tool, read DTCs.
Is DTC U0019–CAN B BUS active?
Yes
- Go To 2
No
- The condition that caused this code to set is not present at this time. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.
- Perform BODY VERIFICATION TEST VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
2. CHECK FOR ACTIVE CAN B BUS RELATED DTCS IN THE FRONT CONTROL MODULE
With the scan tool, read Front Control Module DTCs
Does the scan tool display any active CAN B BUS related DTCs?
Yes
- Diagnose and repair the DTC(s). (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
No
- Go to 3
3. CHECK (D55) CAN B BUS (+) CIRCUIT FOR AN OPEN
Turn the ignition off.
Disconnect the negative battery cable.
Disconnect the Electronic Overhead Module harness connector.
Disconnect the Front Control Module C1 harness connector.
Measure the resistance of the (D55) Can B Bus (+) circuit between the Front Control Module C1 harness connector and the Electronic Overhead Module harness connector.
Is the resistance below 5.0 ohms?
Yes
- Go To 4
No
- Repair the Can B Bus (+) circuit for an open.
- Perform BODY VERIFICATION TEST VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
4. CHECK THE (D54) CAN B BUS (–) CIRCUIT FOR AN OPEN
Measure the resistance of the (D54) Can B Bus (–) circuit between the Front Control Module C1 harness connector and the Electronic Overhead Module harness connector.
Is the resistance below 5.0 ohms?
Yes
- Replace the Electronic Overhead Module in accordance with the service information.
- Perform BODY VERIFICATION TEST VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
No
- Repair the Can B Bus (–) circuit for an open.
- Perform BODY VERIFICATION TEST VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)