U1107-ECU IN SINGLE-WIRE MODE - HSM
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
Continuously.
- Set Condition:
This code will set if either the Can B Bus (+) or (-) circuits are open.
| Possible Causes |
| CAN B BUS DTC's IN FRONT CONTROL MODULE |
| (D54) CAN B BUS (–) CIRCUIT OPEN |
| (D55) CAN B BUS (+) CIRCUIT OPEN |
| HEATED SEAT MODULE |
Diagnostic Test
1. TEST FOR INTERMITTENT CONDITIONTurn the ignition on.
With the scan tool, record and erase DTC's
Cycle the ignition from on to off three times.
Turn the ignition on.
With the scan tool, read DTC's.
Does the scan tool display U1107 ECU IN SINGLE-WIRE MODE?
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.
- (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
2. CHECK FRONT CONTROL MODULE DTC's
With the scan tool, read Front Control Module DTC's
Does the scan tool display any CAN B BUS DTC's – ACTIVE?
Yes
- Refer to the symptom list for problems related to Communication (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING)
No
- Go to 3
3. CAN B BUS (+) CIRCUIT OPEN
Turn the ignition off.
Disconnect the Heated Seat Module connector.
Disconnect the Front Control Module C1 connector.
Measure the resistance of the (D55) Can B Bus (+) circuit between the Front Control Module C1 connector and the Heated Seat Module connector.
Is the resistance below 2.0 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. CAN B BUS (–) CIRCUIT OPEN
Measure the resistance of the (D54) Can B Bus (–) circuit between the Front Control Module C1 connector and the Heated Seat Module connector.
Is the resistance below 2.0 ohms?
Yes
- Replace the Heated Seat Module.
- 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)