INSPECTION PROCEDURE 3: TCL/ASC-ECU Power Supply System: Diagnosis

Required Special Tools:

MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A
MB991952: ABS Check Harness

STEP 1. Measure the voltage at TCL/ASC-ECU connector A-32.
1. Disconnect the connector A-32, and connect special tool ABS Check Harness (MB991952) to the wiring harness-side connector.
  NOTE: Do not connect special tool ABS Check Harness (MB991952) to the TCL/ASC-ECU.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 32 and ground. It should measure approximately 12 volts (battery positive voltage).
Q: Is battery positive voltage (approximately 12 volts) present?
1. YES : Go to Step 3.
2. NO : Go to Step 2.
Fig 1: Measuring Voltage At TCL/ASC-ECU Connector A-32
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 2. Check the following connectors.
- TCL/ASC-ECU connector A-32
  
  Fig 2: Identifying TCL/ASC-ECU Connector A-32
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
- Junction block connectors C-214 and C-215
  
  Fig 3: Identifying Junction Block Connectors C-214 And C-215
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
- Joint connector (1) C-04
  
  Fig 4: Identifying Joint Connector C-04
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
- Ignition switch connector C-308
Check the connectors, for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition?
1. YES : An open or short circuit may be present in the power supply line to the TCL/ASC-ECU. Repair the wiring harness between TCL/ASC-ECU connector A-32 terminal 32 and ignition switch connector C-308 terminal 4. Go to Step 8.
2. NO : Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Then go to Step 8.
Fig 5: Identifying Ignition Switch Connector C-308
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 3. Measure the resistance at TCL/ASC-ECU connector A-32.
1. Disconnect the connector A-32, and connect special tool ABS Check Harness (MB991952) to the wiring harness-side connector.
  NOTE: Do not connect special tool ABS Check Harness (MB991952) to the TCL/ASC-ECU.
2. Measure the resistance between terminal 12, 34 and ground. It should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
1. YES : Go to Step 5.
2. NO : Go to Step 4.
Fig 6: Measuring Resistance At TCL/ASC-ECU Connector A-32
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 4. Check TCL/ASC-ECU connector A-32 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are the connectors and terminals in good condition?
1. YES : An open circuit may be present in the ground circuit. Repair the wiring harness between TCL/ASC-ECU connector A-32 terminals 12, 34 and the body ground. Then go to Step 8.
2. NO : Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Then go to Step 8.
Fig 7: Identifying TCL/ASC-ECU Connector A-32
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 5. Check the battery.
Check the battery (Refer to BATTERY TEST ).

Q: Is the battery in good condition?
1. YES : Go to Step 6.
2. NO : Charge or replace the battery. Then go to Step 8.
STEP 6. Check the charging system.
Check the charging system (Refer to CHARGING SYSTEM DIAGNOSIS ).

Q: Is the charging system in good condition?
1. YES : Go to Step 7.
2. NO : Repair or replace the charging system component(s). Then go to Step 8.
STEP 7. Retest the system.
Q: Can the TCL/ASC-ECU communicate with the scan tool (MUT-III Sub Assembly)?
1. YES : It can be assumed that this malfunction is intermittent.
  Refer to How To Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
2. NO : Replace the TCL/ASC-ECU. Then go to Step 8.
STEP 8. Retest the system.
Q: Can the TCL/ASC-ECU communicate with the scan tool (MUT-III Sub Assembly)?
1. YES : The procedure is complete.
2. NO : Go to Step 1.