INSPECTION PROCEDURE 3: TCL/ASC-ECU power supply circuit system: Diagnosis

Required Special Tools:

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
MB991997: ASC Check Harness

STEP 1. Measure the voltage at TCL/ASC-ECU connector A-38.
1. Disconnect the connector A-38, and connect special tool MB991997 to the wiring harness-side connector.
  NOTE: Do not connect special tool MB991997 to the TCL/ASC-ECU.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 4 and ground. It should measure approximately 12 volts (battery positive voltage).
Q: Is battery positive voltage (approximately 12 volts) present?

YES : Go to Step 3.

NO : Go to Step 2.

Fig 1: Measuring Voltage At TCL/ASC-ECU Connector A-38
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 2. Check the following connectors.
- TCL/ASC-ECU connector A-38
  
  Fig 2: Locating TCL/ASC-ECU Connector A-38
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
- Junction block connectors C-202 and C-203
  
  Fig 3: Locating Junction Block Connectors C-202 And C-203
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
- Intermediate connector C-24
  
  Fig 4: Locating Intermediate Connector C-24
  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?

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-38 terminal 4 and ignition switch connector C-308 terminal 4. Go to Step 8.

NO : Repair or replace the damaged component(s). Refer to HARNESS INSPECTION and CONNECTOR INSPECTION SERVICE POINTS . Then go to Step 8.

Fig 5: Locating Ignition Switch Connector C-308
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 3. Measure the resistance at TCL/ASC-ECU connector A-38.
1. Disconnect the connector A-38, and connect special tool MB991997 to the wiring harness-side connector.
  NOTE: Do not connect special tool MB991997 to the TCL/ASC-ECU.
2. Measure the resistance between terminal 16, 47 and ground. It should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 5.

NO : Go to Step 4.

Fig 6: Measuring Resistance Between Terminal 16, 47 And Ground
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 4. Check TCL/ASC-ECU connector A-38 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are the connectors and terminals in good condition?

YES : An open circuit may be present in the ground circuit. Repair the wiring harness between TCL/ASC-ECU connector A-38 terminals 16, 47 and the body ground. Then go to Step 8.

NO : Repair or replace the damaged component(s). Refer to HARNESS INSPECTION and CONNECTOR INSPECTION SERVICE POINTS . Then go to Step 8.

Fig 7: Locating TCL/ASC-ECU Connector A-38
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?

YES : Go to Step 6.

NO : Charge or replace the battery. Then go to Step 8.
STEP 6. Check the charging system.
Check the charging system (Refer toCHARGING SYSTEM DIAGNOSIS ).

Q: Is the charging system in good condition?

YES : Go to Step 7.

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 (M.U.T.-III Sub Assembly)?

YES : It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

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 (M.U.T.-III Sub Assembly)?

YES : The procedure is complete.

NO : Go to Step 1.