DTC U1515: No-Bus activity error (LIN): 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: Vehicles 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)

STEP 1. Check the following connectors.
Check the following connectors:
- Column switch connector C-201
- ETACS-ECU connectors C-301 and C-316
- Sunroof motor assembly connector D-05 <Vehicles with sunroof>
- Lighting control sensor connector D-42 <Vehicles with auto light function>
- Power window main switch connector E-28 <Vehicles with central door locking system>
  Q: Are all the connectors in good condition?
  - YES: Go to Step 2.
  - NO: Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION .
STEP 2. Check the following wiring harness.
Check the wiring harness for open circuit between the following connectors:
- Wiring harness from ETACS-ECU connector C-301 (terminal 1) to column switch connector C-201 (terminal 3)
- Wiring harness from ETACS-ECU connector C-316 (terminal 1) to lighting control sensor connector D-42 (terminal 3) <Vehicles with auto light function>
- Wiring harness from ETACS-ECU connector C-316 (terminal 1) to sunroof motor assembly connector D-05 (terminal 7) <Vehicles with sunroof>
- Wiring harness from ETACS-ECU connector C-301 (terminal 1) to power window main switch connector E-28 (terminal 7) <Vehicles with central door locking system>
  NOTE: Also check joint connector C-02 and intermediate connector C-126 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-02 or intermediate connector C-126 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .
  
  Q: Are all the wiring harness wires in good condition?
  - YES: Go to Step 3.
  - 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.
STEP 3. Measure the voltage at the LIN bus lines.
Check the LIN bus lines for short to power supply.
1. Disconnect all the ECU connectors which are connected to the LIN bus lines.
2. Turn the ignition switch from "LOCK" (OFF) to "ON" position.
3. Measure the voltage between column switch connector C-201 (terminal 3) and ground.
  - The voltmeter needle does not swing.
    NOTE: If the LIN bus lines are short to power supply, the voltmeter indicates a constant value.
    
    Fig 1: Measuring Voltage Between Column Switch Connector C-201 (Terminal 3) And Ground
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Measure the voltage between sunroof motor assembly connector D-05 (terminal 7) and ground. <Vehicles with sunroof>
  - The voltmeter needle does not swing.
    NOTE: If the LIN bus lines are short to power supply, the voltmeter indicates a constant value.
    
    Fig 2: Measuring Voltage Between Sunroof Motor Assembly Connector D-05 (Terminal 7) And Ground
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. Measure the voltage between lighting control sensor connector D-42 (terminal 3) and ground. <Vehicles with auto light function>
  - The voltmeter needle does not swing.
    NOTE: If the LIN bus lines are short to power supply, the voltmeter indicates a constant value.
    
    Q: Is the check result normal?
    - YES: Go to Step 4.
    - 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.
      
      Fig 3: Measuring Voltage Between Lighting Control Sensor Connector D-42 (Terminal 3) And Ground
      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 4. Measure the resistance at the LIN bus lines.
Check the LIN bus lines for short to ground.
1. Disconnect all the ECU connectors which are connected to the LIN bus lines.
2. Measure the resistance value between column switch connector C-201 (terminal 3) and ground.
  - No continuity (1 kΩ or more)
    
    Fig 4: Measuring Resistance Value Between Column Switch Connector C-201 (Terminal 3) And Ground
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Measure the resistance value between sunroof motor assembly connector D-05 (terminal 7) and ground. <Vehicles with sunroof>
  - No continuity (1 kΩ or more)
    
    Fig 5: Measuring Resistance Value Between Sunroof Motor Assembly Connector D-05 (Terminal 7) And Ground
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Measure the resistance value between lighting control sensor connector D-42 (terminal 3) and ground. <Vehicles with auto light function>
  - No continuity (1 kΩ or more)
    Q: Is the check result normal?
    - YES: Go to Step 5.
    - 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.
      
      Fig 6: Measuring Resistance Value Between Lighting Control Sensor Connector D-42 (Terminal 3) And Ground
      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 5. Check the column switch.
Disconnect column switch connector C-201, and recheck whether DTC U1515 is set.

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 THE SCAN TOOL (M.U.T.-III) ."
2. Connect all the relevant ECUs, and disconnect column switch connector C-201 only.
3. Erase the DTC.
4. Turn the ignition switch from "LOCK" (OFF) to "ON" position.
5. Check whether DTC U1515 is set.
  NOTE: If DTC U1515 is not set, DTC U1109 is set because the column switch is disconnected. This is normal.
6. Turn the ignition switch to the "LOCK" (OFF) position.
  Q: Is DTC U1515 set?
  - YES: Reconnect the column switch connector, and go to Step 6.
  - NO: Replace the column switch.
    
    Fig 7: Connecting Special Tool To Data Link Connector
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
STEP 6. Check the power window main switch.
Disconnect power window main switch connector E-28, and recheck whether DTC U1515 is set.
1. Connect all the relevant ECUs, and disconnect power window main switch connector E-28 only.
2. Erase the DTC.
3. Turn the ignition switch from "LOCK" (OFF) to "ON" position.
4. Check whether DTC U1515 is set.
  NOTE: If DTC U1515 is not set, DTC U0215 is set because the power window main switch is disconnected. This is normal.
5. Turn the ignition switch to the "LOCK" (OFF) position.
  Q: Is DTC U1515 set?
  - YES: Reconnect the power window main switch connector, and go to Step 7.
  - NO: Replace the power window main switch.
STEP 7. Check the sunroof motor assembly.
Disconnect sunroof motor assembly connector D-05, and recheck whether DTC U1515 is set.
1. Connect all the relevant ECUs, and disconnect sunroof motor assembly connector D-05 only.
2. Erase the DTC.
3. Turn the ignition switch from "LOCK" (OFF) to "ON" position.
4. Check whether DTC U1515 is set.
  NOTE: If DTC U1515 is not set, DTC U0169 is set because the sunroof motor assembly is disconnected. This is normal.
5. Turn the ignition switch to the "LOCK" (OFF) position.
  Q: Is DTC U1515 set?
  - YES: Reconnect the sunroof motor assembly connector, and go to Step 8.
  - NO: Replace the sunroof motor assembly.
STEP 8. Check the lighting control sensor.
Disconnect lighting control sensor connector D-42, and recheck whether DTC U1515 is set.
1. Connect all the relevant ECUs, and disconnect lighting control sensor connector D-42 only.
2. Erase the DTC.
3. Turn the ignition switch from "LOCK" (OFF) to "ON" position.
4. Check whether DTC U1515 is set.
  NOTE: If DTC U1515 is not set, DTC U0231 is set because the power lighting control sensor is disconnected. This is normal.
5. Turn the ignition switch to the "LOCK" (OFF) position.
  Q: Is DTC U1515 set?
  - YES: Reconnect the lighting control sensor connector, and go to Step 9.
  - NO: Replace the lighting control sensor.
STEP 9. Recheck for diagnostic trouble code.
Check again if the DTC is set to the ETACS-ECU.
1. Erase the DTC.
2. Turn the ignition switch from "LOCK" (OFF) to "ON" position.
3. Check whether DTC U1515 is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
  Q: Is the DTC set?
  - YES: Replace the ETACS-ECU.
  - NO: The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).