Inspection Procedure 1: The rear display unit does not display at all.: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe
• 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. Using scan tool MB991958, read the diagnostic trouble code. 

   Check if the DTC is set to the ETACS-ECU.

   Q: Is the DTC set? 

   YES:  Diagnose the ETACS-ECU (Refer to DIAGNOSIS ).

   NO:  Go to Step 2.

2. STEP 2. Check ETACS-ECU connector C-317 and rear display unit connector D-06 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connector C-317 and rear display unit connector D-06 in good condition? 

   YES:  Go to Step 3.

   NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .

3. STEP 3. Check the wiring harness between ETACS-ECU connector C-317 (terminal 1) and rear display unit connector D-06 (terminal 3). 
   NOTE: Also check intermediate connector D-123 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector D-123 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .
   • Check the power supply lines (battery power supply) for open circuit.

   Q: Is the wiring harness between ETACS-ECU connector C-317 (terminal 1) and rear display unit connector D-06 (terminal 3) in good condition? 

   YES:  Go to Step 4.

   NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

4. STEP 4. Using scan tool MB991958, check data list of ETACS. 

   Check the input signal of ACC relay.

   • Turn the ignition switch to the ACC position.
     ACC SWITCH CONDITION CHART
     
     

     Item No.	Item name	Normal conditions
     Item 288	ACC switch	ON

     OK: Normal condition is displayed. 

   Q: Is the check result normal? 

   YES:  Go to Step 5.

   NO:  Refer to INSPECTION PROCEDURE 1 "THE IGNITION SWITCH (ACC) SIGNAL IS NOT RECEIVED" .

5. STEP 5. Check ETACS-ECU connector C-309 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connector C-309 in good condition? 

   YES:  Go to Step 6.

   NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .

6. STEP 6. Check the power supply circuit to the ETACS-ECU. Measure the voltage at ETACS-ECU connector C-309. 
   1. Disconnect ETACS-ECU connector C-309, and measure the voltage available at the wiring harness-side connector.
   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between terminal 2 and ground.

      OK: The voltage should measure approximately 12 volts (battery positive voltage). 

   Q: Is the measured voltage approximately 12 volts (battery positive voltage)? 

   YES:  Go to  Step 8.

   NO:  Go to Step 7.

   Fig 1: Measuring Voltage Between Terminal 2 And Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. Check the wiring harness between ETACS-ECU connector C-309 (terminal 2) and fusible link No. 37. 
   • Check the power supply line for open circuit and short circuit.

   Q: Is the wiring harness between ETACS-ECU connector C-309 (terminal 2) and fusible link No. 37 in good condition? 

   YES:  Go to Step 8.

   NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

8. STEP 8. Check ETACS-ECU connector C-315 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connector C-315 in good condition? 

   YES:  Go to Step 9.

   NO:  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .

9. STEP 9. Check the power supply circuit to the ETACS-ECU. Measure the voltage at ETACS-ECU connector C-315. 
   1. Disconnect the connector, and measure at the ETACS-ECU side connector.
   2. Turn the ignition switch to the "ACC" position.
   3. Measure voltage between terminal 9 and ground.

      OK: Battery voltage 

   Q: Is the measured voltage battery voltage? 

   YES:  Go to Step 10.

   NO:  Replace the ETACS-ECU.

   Fig 2: Measuring Voltage Between Terminal 9 And Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
10. STEP 10. Check the wiring harness between ETACS-ECU connector C-315 (terminal 9) and rear display unit connector D-06 (terminal 4). 
    NOTE: Also check intermediate connector D-123 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector D-123 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .
    • Check the power supply lines (ACC power supply) for open circuit.

    Q: Is the wiring harness between ETACS-ECU connector C-315 (terminal 9) and rear display unit connector D-06 (terminal 4) in good condition? 

    YES:  Go to Step 11.

    NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

11. STEP 11. Check the ground circuit to the rear display unit. Measure the resistance at rear display unit connector D-06. 
    1. Disconnect rear display unit connector D-06, and measure the resistance available at the wiring harness side of the connector.
    2. Measure the resistance between terminal 1 and ground.

       OK: The resistance should be 2 ohms or less 

    Q: Is the measured resistance 2 ohms or less? 

    YES:  Go to  Step 13.

    NO:  Go to Step 12.

    Fig 3: Measuring Resistance Between Terminal 1 And Ground

    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
12. STEP 12. Check the wiring harness between rear display unit connector D-06 (terminal 1) and ground. 
    NOTE: Also check intermediate connector D-123 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector D-123 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .
    • Check the ground wires for open circuit.

    Q: Is the wiring harness between rear display unit connector D-06 (terminal 1) and ground in good condition? 

    YES:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).

    NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

13. STEP 13. Check if the rear display unit displays normally. 

    Q: Do the rear display unit displays normally? 

    YES:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).

    NO:  Replace the rear display unit.