DTC 21
DTC 021: Failures Information on Combination MeterCAUTION: If DTC 021 is set in the multi-center display, always diagnose the CAN bus lines
CIRCUIT OPERATION
Refer to P54A-244
DTC SET CONDITION
The multi-center display unit (middle grade type) communicates with the combination meter via CAN bus lines If failure information is sent to the combination meter, DTC 021 will be set
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
- The combination meter or the multi-center display unit (middle grade type) may be defective
Past trouble
- Carry out diagnosis with particular emphasis on connector(s) or wiring harness between the combination meter and the multi-center display unit (middle grade type) For diagnosis procedures, refer to "How to cope with past trouble" (Refer to How to Use Troubleshooting/Inspection Service Points)
TROUBLESHOOTING HINTS
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- Malfunction of combination meter
- Malfunction of multi-center display unit (middle grade type)
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (VCI)
- MB991827: MUT-III USB Cable
- MB991911: 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 6
STEP 2 Using scan tool MB991958, read combination meter diagnostic trouble code
Check that the combination meter sets a DTC
Q: Is the DTC set?
YES: Diagnose the SWS system by referring to GROUP 54B, SWS Diagnosis - Diagnostic Trouble Code Chart P54B-29
NO: Go to Step 3
STEP 3 Using scan tool MB991958, read the diagnostic trouble code related to the other system
Check if a DTC, which relates to CAN communication-linked systems, is set
ETACS-ECU
- DTC 021: Information on failures in combination meter via CAN communication
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 lines between the combination meter and the multi-center display unit (middle grade type) (Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction)
NO: Replace combination meter 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 lines between the combination meter and the multi-center display unit (middle grade type) (Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction)
NO: Replace multi-center display unit (middle grade type) 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