U1206
DTC U1206: Flag invalidCAUTION: If DTC U1206 is set in the combination meter, diagnose the CAN main bus line
TROUBLE JUDGMENT
When the ignition switch is in the LOCK (OFF) position, the combination meter receives door-open signal or communication standby instruction from the ETACS-ECU and keeps CAN communication If there is a contradiction between these two signals, DTC U1206 will be set
COMMENTS ON TROUBLE SYMPTOM
Current trouble
- The door switch system of the ETACS-ECU, the ETACS-ECU, or the combination meter may be defective
Past trouble
- Carry out diagnosis with particular emphasis on connector(s) or wiring harness between the ETACS-ECU and the door switch, and the power supply system to the ETACS-ECU For diagnosis procedures, refer to "How to cope with past trouble" (Refer to How to Use Troubleshooting/Inspection Service Points )
Possible causes
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- Malfunction of ETACS-ECU
- Malfunction of combination meter
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (VCI)
- MB991827: MUT-III USB Cable
- MB991910: MUT-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 (Refer to Diagnosis in Information Bus,-Can Bus Diagnostic Chart) On completion, go to Step 4
STEP 2 Using scan tool MB991958, read the ETACS-ECU diagnostic trouble code
Check that the ETACS-ECU sets a DTC
Q: Is the DTC set?
YES: Diagnose the SWS system by referring to P54B-29
NO: Go to Step 3
STEP 3 Replace the ETACS-ECU and then recheck the DTC
Replace the ETACS-ECU, and then check that the DTC is not reset
Q: Is the check result satisfactory?
YES: Go to Step 4
NO: Replace combination meter and then go to step 4
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: The procedure is complete
NO: Go to Step 1