U0001-CAN C BUS CIRCUIT
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
With the ignition on.
- Set Condition:
The FCM detects a short in either CAN C Bus circuit.
| Possible Causes |
| (D65) CAN C BUS (+) CIRCUIT SHORTED TO GROUND |
| (D64) CAN C BUS (-) CIRCUIT SHORTED TO GROUND |
| (D65) CAN C BUS (+) CIRCUIT SHORTED TO VOLTAGE |
| (D64) CAN C BUS (-) CIRCUIT SHORTED TO VOLTAGE |
| (D65) CAN C BUS (+) CIRCUIT SHORTED TO (D64) CAN C BUS (-) CIRCUIT |
| ANTILOCK BRAKE MODULE |
| POWERTRAIN CONTROL MODULE |
| SHIFT LEVER ASSEMBLY |
| STEERING CONTROL MODULE |
| FINAL DRIVE CONTROL MODULE |
| ENGINE CONTROL MODULE (DIESEL ONLY) |
| TRANSMISSION CONTROL MODULE (3.7L/DIESEL ONLY) |
| FRONT CONTROL MODULE |
Diagnostic Test
1. TEST FOR INTERMITTENT CONDITIONTurn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 2
No
- The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
2. ANTILOCK BRAKE MODULE — INTERNAL SHORT
Turn the ignition off.
NOTE: Answer yes if the vehicle is not equipped with this module.
Disconnect the Antilock Brake Module harness connector.
Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 3
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace the Antilock Brake Module in accordance with the service information.
- Perform ABS VERIFICATION TEST — VER 1.
3. POWERTRAIN CONTROL MODULE — INTERNAL SHORT
Turn the ignition off.
NOTE: Answer yes if the vehicle is not equipped with this module.
Disconnect the Powertrain Control Module C1 harness connector.
Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 4
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace and program the Powertrain Control Module in accordance with the service information.
- Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 5.
4. SHIFT LEVER ASSEMBLY (IF EQUIPPED) — INTERNAL SHORT
Turn the ignition off.
NOTE: Answer yes if the vehicle is not equipped with this module.
Disconnect the Shift Lever Assembly harness connector.
Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 5
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace the Shift Lever Assembly in accordance with the service information.
- Perform VERIFICATION TEST VER 1.
5. STEERING CONTROL MODULE — INTERNAL SHORT
Turn the ignition off.
NOTE: Answer yes if the vehicle is not equipped with this module.
Disconnect the Steering Control Module C1 harness connector.
Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 6
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace the Steering Control Module in accordance with the service information.
- Perform VERIFICATION TEST VER - 1.
6. FINAL DRIVE CONTROL MODULE (IF EQUIPPED)— INTERNAL SHORT
Turn the ignition off.
NOTE: Answer yes if the vehicle is not equipped with this module.
Disconnect the Final Drive Control Module C2 harness connector.
Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 7
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace the Final Drive Control Module in accordance with the service information.
- Perform FDCM VERIFICATION TEST VER - 1.
7. ENGINE CONTROL MODULE (DIESEL ONLY) — INTERNAL SHORT
Turn the ignition off.
NOTE: Answer yes if the vehicle is not equipped with this module.
Disconnect the Engine Control Module harness connectors.
Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 8
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace and program the Engine Control Module in accordance with the service information.
- Perform POWERTRAIN VERIFICATION TEST VER - 1.
8. TRANSMISSION CONTROL MODULE (3.7L/DIESEL ONLY) — INTERNAL SHORT
Turn the ignition off.
NOTE: Answer yes if the vehicle is not equipped with this module.
Disconnect the Transmission Control Module C2 harness connector.
Turn the ignition on.
With the scan tool, record and erase FCM DTC's.
Cycle the ignition from on to off 3 times.
Turn the ignition on.
With the scan tool, read active FCM DTC's.
Does the scan tool display U0001–CAN C BUS CIRCUIT as active?
Yes
- Go To 9
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace and program the Transmission Control Module in accordance with the service information.
- Perform TRANSMISSION VERIFICATION TEST VER.
9. (D65) CAN C BUS (+) CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the Front Control Module C1 harness connector.
Turn the ignition on.
Measure the voltage between the (D65) CAN C Bus (+) circuit and ground.
Is there any voltage present?
Yes
- Repair the (D65) CAN C Bus (+) circuit for a short to voltage.
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 10
10. (D64) CAN C BUS (-) CIRCUIT SHORTED TO VOLTAGE
Measure the voltage between the (D64) CAN C Bus (-) circuit and ground.
Is there any voltage present?
Yes
- Repair the (D64) CAN C Bus (-) circuit for a short to voltage.
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 11
11. (D65) CAN C BUS (+) CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Measure the resistance between ground and the (D65) CAN C Bus (+) circuit.
Is any resistance present?
Yes
- Repair the (D65) CAN C Bus (+) circuit for a short to ground.
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 12
12. (D64) CAN C BUS (-) CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (D64) CAN C Bus (-) circuit.
Is any resistance present?
Yes
- Repair the (D64) CAN C Bus (-) circuit for a short to ground.
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 13
13. (D65) CAN C BUS (+) CIRCUIT SHORTED TO (D64) CAN C BUS (-) CIRCUIT
Measure the resistance between the (D65) CAN C Bus (+) circuit and the (D64) CAN C Bus (-) circuit.
Is any resistance present?
Yes
- Repair the (D65) CAN C Bus (+) circuit for a short to the (D64) CAN C Bus (-) circuit.
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace and program the Front Control Module in accordance with the service information.
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).