DTC 23: Engine Control Module (ECM) And Its Related Components: Diagnosis

Required Special Tools: 

• MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
• MB992745: V.C.I.-Lite main harness A
• MB992747: V.C.I.-Lite USB cable short
• MB992748: V.C.I.-Lite USB cable long
• MB991958: Scan Tool (M.U.T.-III Sub Assembly)
  • MB991824: Vehicles 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)

1. STEP 1. Check the MFI system DTC 
   CAUTION: To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).

   Using scan tool (M.U.T.-III), perform MFI system DTC (Refer to DIAGNOSIS FUNCTION).

   Q: Is any DTC set? 

   YES:  Repair the MFI system (Refer to DIAGNOSTIC TROUBLE CODE ). Then go to Step  3

   NO:  Go to Step 2

2. STEP 2. Read the DTC 
   1. Disconnect the negative battery terminal, to erase the DTC of the cruise control system.
   2. Turn the ignition switch to the "ON" position, and press the cruise control ON/OFF switch to turn the cruise control system to ON (the cruise control indicator lamp is turned on).
   3. After turning the cruise control system to ON, when two minutes or more has elapsed without operating the cruise control switches, read the DTC of the cruise control system (Refer to DIAGNOSTIC TROUBLE CODE CHART). 

   Q: Is DTC 23 set? 

   YES:  Replace the ECM Refer to ENGINE CONTROL MODULE (ECM) . Then go to Step 3.

   NO:  It can be assumed that this malfunction is intermittent (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).

3. STEP 3. Read the DTC 
   1. Disconnect the negative battery terminal, to erase the DTC of the cruise control system.
   2. Turn the ignition switch to the "ON" position, and press the cruise control ON/OFF switch to turn the cruise control system to ON (the cruise control indicator lamp is turned on).
   3. After turning the cruise control system to ON, when two minutes or more has elapsed without operating the cruise control switches, read the DTC of the cruise control system (Refer to DIAGNOSTIC TROUBLE CODE CHART). 

   Q: Is DTC 23 set? 

   YES:  Return to Step  1

   NO:  This procedure is complete.