DTC 13
DTC 13: A/C-ECU Time-outCAUTION:
- If DTC 13 is set in the multi-center display, always diagnose the CAN bus lines.
- Before replacing the multi-center display, ensure that the power supply circuit and the ground circuit are normal. (Check that the voltage is 10 V or more.)
NOTE: When the DTC relating to the CAN communication error are set, make sure of the vehicle equipment. When the vehicle is not equipped with the system the multi-center display communicates to, the DTC is always set. This is not abnormal.
CIRCUIT OPERATION
The multi-center display communicates with the A/C-ECU via CAN bus lines.
DTC SET CONDITION
When the multi-center display can not receives necessary signals from the A/C-ECU via CAN bus lines. If the multi-center display can not receives the necessary A/C-ECU signals, DTC 13 will be set.
TECHNICAL DESCRIPTION (COMMENT)
CAUTION: If the ignition switch is turned to the ON position without starting the engine, DTC (past trouble) 11, 12 and 14 may be set to the multi-center display after three minutes.
Current trouble
- Connector(s) or wiring harness in the CAN bus lines between the A/C-ECU and the multi-center display, the power supply system to the display unit, the multi-center display itself, or the A/C-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 A/C-ECU and the multi-center display, and the power supply system to the A/C-ECU.
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, 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. (Refer to CAN bus line Diagnostics Flow. Explanation About the Scan Tool (M.U.T.-III) CAN Bus Diagnostics
TROUBLESHOOTING HINTS
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
- Malfunction of A/C-ECU
- Malfunction of multi-center display
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 (Vehicles with CAN communication system)
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 A/C diagnostic trouble code
Check if an A/C system DTC is set.
Q: Is the DTC set?
YES : Diagnose the A/C system by referring to Manual A/C Diagnosis - Diagnostic Trouble Code Chart Diagnostic Trouble Code Descriptions or Auto A/C Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
NO : Go to Step 3.
STEP 3. Using scan tool MB991958, read the diagnostic trouble code.
Check if a DTC, which relates to CAN communication-linked systems below, is set.
Powertrain control module
- DTC U1110: A/C-ECU time-out
ETACS-ECU
- DTC U1110: A/C-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 DTC set?
YES : Replace A/C-ECU and then go to step 6.
NO : A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the A/C-ECU and the middle grade multi-center display unit.
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 DTC set?
YES : Replace the multi-center display and then go to step 6.
NO : A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the A/C-ECU and the middle grade multi-center display unit.
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 DTC set?
YES : Go to Step 1.
NO : the procedure is complete.