DTC 21
DTC 21: Failures Information on Combination MeterCAUTION:
- If DTC 21 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.)
DTC SET CONDITION
The multi-center display communicates with the combination meter via CAN bus lines. If failure information is sent to the combination meter, DTC 21 will be set.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
- The combination meter or the multi-center display 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.
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
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 combination meter diagnostic trouble code.
Check that the combination meter sets a DTC.
Q: Is the DTC set?
YES : Diagnose the combination meter by referring to Combination meter Diagnosis - Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
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 below, is set.
ETACS-ECU
- DTC U1128: Failure information on combination meter
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 combination meter and then go to step 6.
NO : A poor connection, open circuit or other intermittent malfunction is present in the lines between the combination meter and the multi-center display.
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 multi-center display and then go to step 6.
NO : A poor connection, open circuit or other intermittent malfunction is present in the lines between the combination meter and the multi-center display.
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.