Inspection Procedure 10: Driver's door unlock sensor does not work: Diagnosis

WARNING: This page is about a different car, the 2008 Mitsubishi Lancer. However, it is still accessible from the selected car via links, so may be relevant.

Required Special Tools:

MB992006: Extra fine probe
MB991223: Harness set
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

STEP 1. Using scan tool MB991958, read the diagnostic trouble code.
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 SCAN TOOL (M.U.T.-III) ".
  
  Fig 1: Connecting Special Tool MB991910 To Data Link Connector
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. Turn the ignition switch to the "ON" position.
3. Check whether the KOS-ECU related DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the KOS-ECU. Refer to DIAGNOSTIC TROUBLE CODE CHART .

NO : Go to Step 2.
STEP 2. Check KOS-ECU connector C-05 and unlock sensor (front door: LH) connector E-18 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are KOS-ECU connector C-05 and unlock sensor (front door: LH) connector E-18 in good condition?

YES : Go to Step 3.

NO : Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Check that the driver's door unlock sensor works normally.
STEP 3. Check the wiring harness between the KOS-ECU connector C-05 (terminal Nos. 24, 36) and unlock sensor (front door: LH) connector E-18 (terminal Nos. 4, 2), and between unlock sensor (front door: LH) connector E-18 (terminal No. 6) and ground for open circuit.
1. Disconnect KOS-ECU connector C-05 and unlock sensor (front door: LH) connector E-18, and check the wiring harness.
2. Check the wiring harness between KOS-ECU connector C-05 (terminal No.24) and unlock sensor (front door: LH) connector E-18 (terminal No.4).
  OK: Continuity exists (2 Ω or less)
  
  Fig 2: Checking Continuity Between Connector C-05 And E-18 Terminal 24 And 4
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Check the wiring harness between KOS-ECU connector C-05 (terminal No.36) and unlock sensor (front door: LH) connector E-18 (terminal No.2).
  OK: Continuity exists (2 Ω or less)
  
  Fig 3: Checking Continuity Between Connector C-05 And E-18 Terminal 36 And 2
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Check the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No.6) and ground.
  OK: Continuity exists (2 Ω or less)
  
  Fig 4: Checking Wiring Harness Between Unlock Sensor (Front Door LH) Connector E-18 Terminal 6 And Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Is the wiring harness between KOS-ECU connector C-05 (terminal Nos. 24, 36) and unlock sensor (front door: LH) connector E-18 (terminal Nos. 4, 2), and between unlock sensor (front door: LH) connector E-18 (terminal No. 6) and ground in good condition?

YES : Go to Step 4.

NO (KOS-ECU connector C-05 terminal No.24 - unlock sensor (front door: LH) connector E-18 terminal No.4.) : Repair the wiring harness between KOS-ECU connector C-05 (terminal No.24) and unlock sensor (front door: LH) connector E-18 (terminal No.4).

NO (KOS-ECU connector C-05 terminal No.36 - unlock sensor (front door: LH) connector E-18 terminal No.2.) : Repair the wiring harness between KOS-ECU connector C-05 (terminal No.36) and unlock sensor (front door: LH) connector E-18 (terminal No.2).

NO (unlock sensor (front door: LH) connector E-18 terminal No.6 - ground.) : Repair the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No.6) and ground.
STEP 4. Check the wiring harness between the unlock sensor (front door: LH) connector E-18 (terminal Nos. 4, 2, 6) and the ground for short circuit.
1. Disconnect unlock sensor (front door: LH) connector E-18, and check the wiring harness.
2. Check the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No. 4) and ground
  OK: No continuity
  
  Fig 5: Checking Wiring Harness Between Unlock Sensor (Front Door LH) Connector E-18 Terminal 4 And Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. Check the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No. 2) and ground
  OK: No continuity
  
  Fig 6: Checking Wiring Harness Between Unlock Sensor (Front Door LH) Connector E-18 Terminal 2 And Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. Check the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No.6) and ground.
  OK: No continuity
  
  Fig 7: Checking Wiring Harness Between Unlock Sensor (Front Door LH) Connector E-18 Terminal 6 And Ground
  Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Is the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal Nos. 4, 2, 6) and the ground in good condition?

YES : Go to Step 5.

NO [unlock sensor (front door: LH) connector E-18 terminal No.4 - ground.] : Repair the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No.4) and ground.

NO [unlock sensor (front door: LH) connector E-18 terminal No.2 - ground.] : Repair the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No.2) and the ground.

NO [unlock sensor (front door: LH) connector E-18 terminal No.6 - ground.] : Repair the wiring harness between unlock sensor (front door: LH) connector E-18 (terminal No.6) and the ground.
STEP 5. KOS communication test
Using scan tool (M.U.T-III), perform the antenna communication test to check that the exterior transmitter antenna (driver's side) communicates normally (Refer to ID CODES REGISTRATION PROCEDURES ).

Q: Is the check result normal?

YES : Go to Step 6.

NO : Perform troubleshooting for the diagnostic trouble code No. B240A (Refer to DTC B240A: FR ANTENNA(OUTDOOR) OPEN ).
STEP 6. Check of the troubles
Operate the unlock sensor (front door: LH) and check that the door can be locked.

Q: Is the check result normal?

YES : The diagnosis is complete.

NO : Replace KOS-ECU and register the ID codes (Refer to ID CODE REGISTRATION NECESSITY JUDGMENT TABLE ).