Inspection Procedure 3: Theft-alarm horn does not sound while the theft-alarm system is triggered.: Diagnosis

Required Special Tools: 

• MB992006: Extra fine probe
• MB991223: Harness set
• 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)

1. STEP 1. Using scan tool MB991958, read the diagnostic trouble code. 

   Check if DTC is set to the ETACS-ECU.

   CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
   1. Connect scan tool MB991958. Refer to "HOW TO CONNECT SCAN TOO (M.U.T.-III)  ".
   2. Turn the ignition switch to the "ON" position.
   3. Check whether the ETACS-ECU related DTC is set.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the DTC set? 

   YES:  Diagnose the ETACS-ECU. Refer to DIAGNOSTIC TROUBLE CODE CHART .

   NO:  Go to Step 2.

   Fig 1: Connecting Special Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Using scan tool MB991958, Check the configuration function. 
   1. Turn the ignition switch to the "ON" position.
   2. Use the ETACS-ECU configuration function to check that the "Alarm" is set to "Enable".
   3. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the "Alarm" set to "Enable"? 

   YES:  Go to Step 3.

   NO:  Use the ETACS-ECU configuration function to set the "Alarm" to "Enable" (Refer to CONFIGURATION FUNCTION ).

3. STEP 3. Check the theft-alarm horn work normally. 

   Connect the battery as shown, and verify that the horn sounds.

   Q: Does horn (HI) work normally? 

   YES:  Go to Step 4.

   NO:  Replace the horn (HI). go to step 4.

   Fig 2: Checking Theft-Alarm Horn Work Normally

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check theft-alarm horn relay connector A-17X for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is theft-alarm horn relay connector A-17X in good condition? 

   YES:  Go to Step 5.

   NO:  Repair the damaged parts.

5. STEP 5. Check the theft-alarm horn relay. 

   Refer to THEFT-ALARM INDICATOR CHECK  .

   Q: Is the theft-alarm horn relay in good condition 

   YES:  Go to Step 6.

   NO:  Replace the theft-alarm horn relay.

6. STEP 6. Measure the voltage at theft-alarm horn relay A-17X. 
   1. Remove the relay, and measure at the relay box side.
   2. Measure the voltage between theft-alarm horn relay connector A-17X (terminal No. 1, 4) and the body ground.
      • 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 3: Measuring Voltage Between Theft-Alarm Horn Relay A-17X Connector Terminal And Body Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. Check the Wiring harness between theft-alarm horn relay connector A-17X (terminal No. 1, 4) and fusible link (36). 

   Check the power supply line for open circuit and short circuit.

   Q: Is the check result normal? 

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

   NO:  Repair the wiring harness between theft-alarm horn relay connector A-17X and fusible link (36).

8. STEP 8. Check theft-alarm horn connector A-58 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is theft-alarm horn connector A-58 in good condition? 

   YES:  Go to Step 9.

   NO:  Repair the damaged parts.

9. STEP 9. Check the Wiring harness between theft-alarm horn connector A-58 (terminal No. 1) and theft-alarm horn relay connector A-17X (terminal No. 3). 

   Check the output lines for open circuit and short circuit.

   NOTE: Before the wiring harness check, check intermediate connector A-03, and then repair them if necessary.

   Q: Is the check result normal? 

   YES:  Go to Step 10.

   NO:  Repair the wiring harness between theft-alarm horn connector A-58 and theft-alarm horn relay connector A-17X.

10. STEP 10. Check ETACS-ECU connector C-312 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

    Q: Is ETACS-ECU connector C-312 in good condition? 

    YES:  Go to Step 11.

    NO:  Repair the damaged parts.

11. STEP 11. Check the Wiring harness between theft-alarm horn relay connector A-17X (terminal No. 2) and ETACS-ECU connector C-312 (terminal No. 15). 

    Check the output lines for open circuit and short circuit.

    Q: Is the check result normal? 

    YES:  Go to Step 12.

    NO:  Repair the wiring harness between theft-alarm horn relay connector A-17X and ETACS-ECU connector C-312.

12. STEP 12. Replace theft-alarm horn. 
    1. Replace the theft-alarm horn.

    Q: Does the theft-alarm work normally? 

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

    NO:  Replace the ETACS-ECU.