DTC 13
DTC 013: A/C-ECU Time-out.CAUTION: If DTC 013 is set in the ETACS-ECU, always diagnose the CAN main bus line.
CAUTION: Whenever the ECU is replaced, ensure that the communication circuit is normal.
TROUBLE JUDGMENT
The ETACS-ECU receives air conditioning system-related signal from the A/C-ECU. If an air conditioning control system-related signal cannot be received, DTC 013 will be set.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
- Connector(s) or wiring harness in the CAN bus lines between the A/C-ECU and the ETACS-ECU, the power supply system to the A/C-ECU, the A/C-ECU, or the ETACS-ECU may be defective.
Past trouble
- If DTC 013 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) in the CAN bus line between the A/C-ECU and the ETACS-ECU, and the power supply system to the A/C-ECU. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to How to Use Troubleshooting/Inspection Service Points).
NOTE: You cannot find a past trouble, by the MUT-III CAN bus diagnostics even if there is a failure in CAN bus lines. In this case, refer to How to Use Troubleshooting/Inspection Service Points-How to Cope with Intermittent Malfunction 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 (Refer to CAN Bus Line Diagnostic Flow). Explanation About The MUT-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
- The A/C-ECU may be defective
- The ETACS-ECU may be defective
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958. Refer to "How to connect SWS monitor." How to Connect SWS Monitor
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES: Go to Step 2.
NO: Repair the CAN bus line (Refer to Diagnosis). Component Tests and General Diagnostics
STEP 2. Using scan tool MB991958, read the A/C diagnostic trouble code.
Check if an A/C-ECU DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check whether A/C system-related DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES: Diagnose the air conditioning system (Refer to Diagnosis). Diagnostic Trouble Code Descriptions
NO: Go to Step 3.
STEP 3. Using scan tool MB991958 check for any diagnostic trouble code.
Check if a DTC, which relates to CAN communication-linked systems below, is set.
- Combination meter
A/C-related time-out DTC
- Multi center display (middle-grade type)
A/C-related time-out DTC
1. Turn the ignition switch to the "ON" position.
2. Check for a DTC related to the relevant system.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES: Go to Step 4.
NO: Go to Step 5.
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES: Replace the A/C-ECU. On completion, check that the DTC is not reset.
NO: A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the A/C-ECU and the ETACS-ECU (Refer to How to Use Troubleshooting/Inspection Service Points-How to Cope with Intermittent Malfunction).
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES: Replace the ETACS-ECU. On completion, check that the DTC is not reset.
NO: A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the A/C-ECU and the ETACS-ECU (Refer to How to Use Troubleshooting/Inspection Service Points-How to Cope with Intermittent Malfunction).