U1104
DTC U1104: SAS CAN Time-out/Not equipped
DIAGNOSIS
CAUTION:
If DTC U1104 is set in the TCL/ASC-ECU, always diagnose the CAN bus lines.
CAUTION:
Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
CIRCUIT OPERATION
The TCL/ASC-ECU and the steering wheel sensor are connected each other via a CAN bus line, and the sensor sends the steering wheel angle information to the ECU.
TCL/ASC DTC SET CONDITIONS
Current trouble
- Connector(s) or wiring harness in the CAN bus lines between the TCL/ASC-ECU and the steering wheel sensor, the power supply system to the steering wheel sensor, the steering wheel sensor itself, or the TCL/ASC-ECU may be defective.
Past trouble
- Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the steering wheel sensor and the TCL/ASC-ECU, and the power supply system to the steering wheel sensor. For diagnosis procedures, refer to "How to cope with past trouble" How to Treat Past Trouble ).
NOTE:
For a past trouble, you may not find it by the M.U.T.-III CAN bus diagnostics even if there is any failure in CAN bus lines. In this case, refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction How to Cope With Intermittent Malfunctions . and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the DTC, which is set regarding the CAN communication-linked ECUs CAN Bus Line Diagnostics Flow ).
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THESE DTCS ARE TO SET ARE:)
- The CAN bus line is defective.
- Malfunction of the hydraulic unit (integrated with TCL/ASC-ECU)
- Malfunction of the steering wheel sensor
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
Use scan tool MB991958 to diagnose the CAN bus lines.
(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to "ON" position.
(3)Diagnose the CAN bus line.
Q. Is the check result satisfactory?
YES Go to Step 2.
NO Repair the CAN bus lines CAN Bus Diagnostics Chartor CAN Bus Diagnostics Chart). On completion, go to Step 6.
STEP 2. Using scan tool MB991958, read the steering wheel sensor diagnostic trouble code.
Check if a steering wheel sensor DTC is set.
Q. Is the DTC set?
YES Diagnose the steering wheel sensor by referring to Active Stability Control System (ASC). Then go to Step 6.
NO Go to Step 3.
STEP 3. Using scan tool MB991958 read any of the diagnostic trouble code.
Check if a DTC, which relates to CAN communication-linked systems below, is set.
Engine control module (ECM) [M/T] or powertrain control module (PCM) [A/T]
- DTC U1102: TCL/ASC-ECU time-out
Combination meter
- DTC U1102: TCL/ASC-ECU time-out
Q. Is the DTC set?
YES Go to Step 4.
NO Go to Step 5.
STEP 4. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to "ON" position.
(3)Check if the DTC is set.
Q. Is the check result satisfactory?
YES A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the steering wheel sensor and the TCL/ASC-ECU How to Cope With Intermittent Malfunctions).
NO Replace hydraulic unit (integrated with TCL/ASC-ECU) and then go to Step 6
.
STEP 5. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to "ON" position.
(3)Check if the DTC is set.
Q. Is the check result satisfactory?
YES A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the steering wheel sensor and the TCL/ASC-ECU How to Cope With Intermittent Malfunctions).
NO Replace steering wheel sensor and then go to Step 6.
STEP 6. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to "ON" position.
(3)Check if the DTC is set.
Q. Is the check result satisfactory?
YES The procedure is complete.
NO Go to Step 1.