U1104

DTC U1104: SAS CAN time-out/Not equipped

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".

NOTE: For a past trouble, you may not find it by the M.U.T.- CAN bus diagnostics even if there is any failure in 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.

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. 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 DIAGNOSTIC TROUBLE CODE CHART. Diagnostic Trouble Code Descriptions
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 power train control module (PCM) [A/T]
^ DTC U1102: ABS-ECU or TCL/ASC-ECU time-out
Combination meter
^ DTC U1102: ABS-ECU or 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 .
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.
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.