Diagnostic Procedure

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

1. STEP 1. Scan tool CAN bus diagnostics 

   Using the scan tool, diagnose the CAN bus lines.

   Q: Is the check result normal? 

   1. YES:  Go to Step 2.
   2. NO:  Repair the CAN bus lines. (Refer to TROUBLESHOOTING .) After repairing the CAN bus line, go to Step 2.
2. STEP 2. Scan tool diagnostic trouble code. 

   Check if the diagnostic trouble code is stored in the system other than TC-SST.

   Q: Is the DTC stored? 

   1. YES:  Perform the relevant troubleshooting.
   2. NO:  Go to Step 3.
3. STEP 3. Scan tool diagnostic trouble code. 

   After 15 seconds with the engine idle status, check that the diagnostic trouble code for engine is stored. (Refer to DIAGNOSTIC TROUBLE CODE TABLE .)

   Q: Is the DTC stored? 

   1. YES:  Perform the relevant troubleshooting.
   2. NO:  Go to Step 4.
4. STEP 4. Check whether the DTC is stored again. 

   After 15 seconds with the engine idle status, check that the DTC is stored again.

   Q: Is DTC No. P1871 stored? 

   1. YES:  Replace the mechatronic assembly. (Refer to << A >> MECHATRONIC ASSEMBLY REMOVAL .)
   2. NO:  Intermittent malfunction. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION .)