DIAGNOSTIC ITEM 1: Diagnose When The Scan Tool Cannot Receive The Data Sent By ETACS-ECU: Diagnosis

WARNING: This page is about a different variant/trim than selected.

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

STEP 1. Check data link connector C-40 and ETACS-ECU connector C-301 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
CAUTION:
The strand end of the twisted wire should be within 10 cm (4 inches) from the connector. For details refer to SERVICE PRECAUTIONS .

Q: Are data link connector C-40 and ETACS-ECU connector C-301 in good condition?
1. YES: Go to Step 2.
2. NO: Repair the damaged parts.
STEP 2. Check the wiring harness between data link connector C-40 and ETACS-ECU connector C-301 for open circuit.
CAUTION:
Strictly observe the specified wiring harness repair procedure. For details refer to SERVICE PRECAUTIONS .
1. Disconnect the scan tool and ETACS-ECU connector C-301, and check the wiring harness.
2. Check the wiring harness between data link connector C-40 (terminal 6) and ETACS-ECU connector C-301 (terminal 5) <CAN_H>
  OK: Continuity exists (2 Ω or less)
  
  Fig 1: Measuring Resistance Between Data Link Connector C-40 Terminal 6 & ETACS-ECU Connector C-301 Terminal 5
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Check the wiring harness between data link connector C-40 (terminal 14) and ETACS-ECU connector C-301 (terminal 4) <CAN_L>
  OK: Continuity exists (2 Ω or less)
  
  Fig 2: Measuring Resistance Between Data Link Connector C-40 Terminal 14 & ETACS-ECU Connector C-301 Terminal 4
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Is the wiring harness between data link connector C-40 and ETACS-ECU connector C-301 in good condition?
1. YES: Go to Step 3.
2. NO: Repair the wiring harness between data link connector C-40 and ETACS-ECU connector C-301.
STEP 3. Check the wiring harness between data link connector C-40 and ETACS-ECU connector C-301 for a short to ground. Measure the resistance at data link connector C-40.
CAUTION:
Disconnect the negative battery terminal. For details refer to SERVICE PRECAUTIONS .

CAUTION:
A digital multimeter should be used. For details refer to SERVICE PRECAUTIONS .

CAUTION:
The test wiring harness should be used. For details refer to SERVICE PRECAUTIONS .
1. Disconnect the scan tool and ETACS-ECU connector C-301, and measure the resistance at the wiring harness side of data link connector C-40.
2. Measure the resistance between data link connector terminal 6 and body ground. <CAN_H>
  OK: 1 kΩ or more
  
  Fig 3: Measuring Resistance Between Data Link Connector Terminal 6 & Body Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Measure the resistance between data link connector terminal 14 and body ground. <CAN_L>
  OK: 1 kΩ or more
  
  Fig 4: Measuring Resistance Between Data Link Connector Terminal 14 & Body Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Do all the resistances measure 1 kΩ or more?
1. YES: Go to Step 4.
2. NO: Repair the wiring harness between data link connector C-40 and ETACS-ECU connector C-301.
STEP 4. Check the wiring harness between data link connector C-40 and ETACS-ECU connector C-301 for a short to the power supply. Measure the voltage at data link connector C-40.
1. Disconnect the scan tool and ETACS-ECU connector C-301, and measure the resistance at the wiring harness side of data link connector C-40.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between data link connector terminal 6 and body ground. <CAN_H>
  OK: 1 V or less
  
  Fig 5: Measuring Voltage Between Data Link Connector Terminal 6 & Body Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Measure the voltage between data link connector terminal 14 and body ground. <CAN_L>
  OK: 1 V or less
  
  Fig 6: Measuring Voltage Between Data Link Connector Terminal 14 & Body Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Do all the voltage measure 1 V or less?
1. YES: Go to Step 5.
2. NO: Repair the wiring harness between data link connector C-40 and ETACS-ECU connector C-301.
STEP 5. Check the wiring harness between data link connector C-40 and ETACS-ECU connector C-301 for line-to-line short. Measure the resistance at data link connector C-40.
1. Disconnect the scan tool and ETACS-ECU connector C-301, and measure the resistance at the wiring harness side of data link connector C-40.
2. Measure the resistance between data link connector terminal 6 and 14.
  OK: No continuity
  
  Fig 7: Measuring Resistance Between Data Link Connector Terminal 6 & 14
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Is the check result normal?
1. YES: Go to Step 6.
2. NO: Repair the wiring harness between data link connector C-40 and ETACS-ECU connector C-301.
STEP 6. Using scan tool MB991958, diagnose the CAN bus line.
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 to the data link connector.
2. Turn the ignition switch to the "ON" position.
  
  Fig 8: Connecting Scan Tool To Data Link Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Diagnose CAN bus lines, and check if the scan tool screen is as shown in the illustrations below.
  
  Fig 9: Screen Display - CAN Bus Lines (M/T)
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
  
  Fig 10: Screen Display - CAN Bus Lines (TC-SST)
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Does the scan tool screen correspond to the illustration?
1. YES: The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
2. NO: Replace the ETACS-ECU.