Body Control System

U0001-CAN C BUS CIRCUIT

U0001 - CAN C BUS Circuit:

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
- Steering angle sensor
- Front control module

Diagnostic Test

1. TEST FOR INTERMITTENT CONDITION
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.

Q: 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.
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.

Q: 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.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

3. POWERTRAIN CONTROL MODULE - INTERNAL SHORT
Turn the ignition off.
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.

Q: 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.
Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 5. Powertrain Verification Test

4. STEERING ANGLE SENSOR - INTERNAL SHORT
Turn the ignition off.
Disconnect the Steering Angle Sensor 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.

Q: 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 and program the Steering Angle Sensor (internal to clockspring).
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

5. (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.

Q: Is there any voltage present?
YES: Repair the (D65) CAN C Bus (+) circuit for a short to voltage.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 6

6. (D64) CAN C BUS (-) CIRCUIT SHORTED TO VOLTAGE




Measure the voltage between the (D64) CAN C Bus (-) circuit and ground.

Q: Is there any voltage present?

YES: Repair the (D64) CAN C Bus (-) circuit for a short to voltage.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 7

7. (D65) CAN C BUS (+) CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Measure the resistance between ground and the (D65) CAN C Bus (+) circuit.

Q: Is any resistance present?

YES: Repair the (D65) CAN C Bus (+) circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 8

8. (D64) CAN C BUS (-) CIRCUIT SHORTED TO GROUND




Measure the resistance between ground and the (D64) CAN C Bus (-) circuit.

Q: Is any resistance present?

YES: Repair the (D64) CAN C Bus (-) circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 9

9. (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.

Q: 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. Body Verification Test
NO: Inspect the wiring and connectors for damage or shorted circuits. If ok, replace and program the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test