U1107

U1107-ECU IN SINGLE-WIRE MODE





For a complete wiring diagram Refer to Diagrams/Electrical.

- When Monitored:

With the ignition on.

- Set Condition:

The FCM detects an open, a short high, a short low or a short together in either of the CAN B Bus circuits.





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.

Does the scan tool display this DTC 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.ANY CAN B BUS MODULE- INTERNAL FAULT

Turn the ignition off.

With the scan tool, monitor the active FCM DTCs.

While monitoring the scan tool, disconnect each CAN B Bus module one at a time.

NOTE: When performing the above step, turn the ignition off (wait one minute) before disconnecting any module. When the module is disconnected turn the ignition on.

NOTE: This is to determine if the fault is internal within a module.

Check for this DTC to become active after disconnecting each CAN B Bus module the vehicle is equipped with.

NOTE: If the DTC becomes stored when a particular CAN B Bus module is disconnected, that module is causing the DTC to set.

With all the CAN B Bus modules disconnected did the FCM still set this DTC as active?

Yes

- Go To 3

No

- Replace the module that when disconnected the DTC became stored.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

3.(D55) CAN B BUS (+) CIRCUIT FOR A SHORT TO VOLTAGE





Turn the ignition off.

Disconnect the Front Control Module C1 harness connector.

NOTE: Ensure each CAN B Bus module is disconnected at this time.

Turn the ignition on.

Measure the voltage between the (D55) CAN B Bus (+) circuit and ground.

Is the voltage above 10.0 volts?

Yes

- Repair the (D55) CAN B Bus (+) circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 4

4.(D54) CAN B BUS (-) CIRCUIT FOR A SHORT TO VOLTAGE





NOTE: Ensure each CAN B Bus module is disconnected at this time.

Measure the voltage between the (D54) CAN B Bus (-) circuit and ground.

Is the voltage above 10.0 volts?

Yes

- Repair the (D54) CAN B Bus (-) circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 5

5.(D55) CAN B BUS (+) CIRCUIT FOR A SHORT TO GROUND





Turn the ignition off.

NOTE: Ensure each CAN B Bus module is disconnected at this time.

Measure the resistance between ground and the (D55) CAN B Bus (+) circuit.

Is the resistance above 1000.0 ohms?

Yes

- Go To 6

No

- Repair the (D55) CAN B Bus (+) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

6.(D54) CAN B BUS (-) CIRCUIT FOR A SHORT TO GROUND





NOTE: Ensure each CAN B Bus module is disconnected at this time.

Measure the resistance between ground and the (D54) CAN B Bus (-) circuit.

Is the resistance above 1000.0 ohms?

Yes

- Go To 7

No

- Repair the (D54) CAN B Bus (-) circuit for a short to ground.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

7. (D55) CAN B BUS (+) CIRCUIT SHORTED TO THE (D54) CAN B BUS (-) CIRCUIT





Measure the resistance between the (D55) CAN B Bus (+) circuit and (D54) CAN B Bus (-) circuit.

NOTE: Ensure each CAN B Bus module is disconnected at this time.

Is any resistance present?

Yes

- Repair the (D55) CAN B Bus (+) circuit for a short to the (D54) CAN B Bus (-) circuit.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 8

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





Measure the resistance of the (D55) CAN B Bus (+) circuit between the FCM connector and the Cluster connector.

Is the resistance above 10.0 ohms?

Yes

- Repair the (D55) CAN B Bus (+) circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 9

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





Measure the resistance of the (D54) CAN B Bus (-) circuit between the FCM connector and the Cluster connector.

Is the resistance above 10.0 ohms?

Yes

- Repair the (D54) CAN B Bus (-) circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Replace and program the Front Control Module.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test