Inspection Procedure 2: Malfunction of the ignition switch (IG1) input/output signal: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Check ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ETACS-ECU connector C-317 in good condition? 

   1. YES:  Go to Step 2.
   2. NO:  Repair or replace the damaged component(s) (Refer to HARNESS CONNECTOR INSPECTION ). Check that the input signal of ignition switch (IG1) is normal.
2. STEP 2. Check the ignition switch (IG1) line of the power supply circuit to the ETACS-ECU. Measure the voltage at ETACS-ECU connector C-317. 
   1. Measure by backprobing without disconnecting the connector.
   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between the terminal No. 6 and the ground.
      • The voltage should measure approximately 12 volts (battery positive voltage).

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

   1. YES:  Go to  Step 5.
   2. NO:  Go to Step 3.
      Fig 1: Measuring Voltage Between Terminal No. 6 And Ground

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Check the ignition switch. 

   Remove the ignition switch. Then check continuity between the switch terminal.

   Ignition key position	Terminal number	Normal condition
   LOCK	1 - 2, 1 - 4, 1 - 5, 1 - 6	No continuity
   ACC	1 - 6	Continuity exists (2 ohms or less)
   ON	1 - 2 - 4 - 6	Continuity exists (2 ohms or less)
   START	1 - 2 - 5	Continuity exists (2 ohms or less)

   Q: Is the ignition switch in good condition? 

   1. YES:  Go to Step 4.
   2. NO:  Replace the ignition switch. Check that the input signal of ignition switch (IG1) is normal.
4. STEP 4. Check the wiring harness between ETACS-ECU connector C-317 (terminal 6) and the ignition switch (IG1). 

   Check the power supply line (IG1) for open circuit and short circuit.

   Q: Is the wiring harness between ETACS-ECU connector C-317 (terminal 6) and ignition switch (IG1) in good condition? 

   1. YES:  Refer to INSPECTION PROCEDURE 2 "DEFECTIVE POWER SUPPLY SYSTEM OF THE IGNITION SWITCH"
   2. 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. Check that the input signal of ignition switch (IG1) is normal.
5. STEP 5. Using scan tool MB991958, check data list. 
   • Ignition switch: ON

     Item No.	Item name	Normal condition
     Item 254	IG voltage	Battery positive voltage

     OK: Normal condition is displayed. 

   Q: Is the check result normal? 

   1. YES:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
   2. NO:  Replace the ETACS-ECU.