DTC C1271: Motor Circuit Failure: Diagnosis

Required Special Tools: 

• MB991958: Scan Tool (MUT-III Sub Assembly)
  • MB991824: V.C.I.
  • MB991827: MUT-III USB Cable
  • MB991910: MUT-III Main Harness A
• MB991997: ASC Check Harness

1. STEP 1. 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.
   3. Diagnose the CAN bus line.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the CAN bus line found to be normal? 

   YES :  Go to  Step 3.

   NO :  Repair the CAN bus line (Refer to DIAGNOSIS ). Then go to Step 2.

   Fig 1: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
2. STEP 2. Recheck for 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. Turn the ignition switch to the "ON" position.
   2. Erase the DTC.
   3. Turn the ignition switch to the "LOCK" (OFF) position.
   4. Turn the ignition switch to the "ON" position.
   5. Check if the DTC is set.
   6. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is DTC C1271 set? 

   YES :  Go to Step 3.

   NO :  The procedure is complete.

   Fig 2: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Measure the voltage at ABS/TCL-ECU connector A-03. 
   1. Disconnect the connector A-03, and connect special tool MB991997 to the wiring harness-side connector.
      NOTE: DO NOT connect special tool MB991997 to the ABS/TCL-ECU.
   2. Turn the ignition switch to the "ON" position.
   3. Measure the voltage between terminal 1 and ground. It should be approximately 12 volts (battery positive voltage).

   Q: Is the voltage approximately 12 volts (battery positive voltage)? 

   YES :  Go to  Step 5.

   NO :  Go to Step 4.

   Fig 3: Measuring Voltage Between Terminal No. 1 & Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check ABS/TCL-ECU connector A-03 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ABS/TCL-ECU connector A-03 damaged? 

   YES :  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Then go to  Step 8.

   NO :  An open or short circuit may be present in the solenoid valve power supply circuit. Repair the wiring harness between ABS/TCL-ECU connector A-03 terminal 1 and fusible link No.3.Then go to  Step 8.

   Fig 4: Identifying Connector A-03 Terminals

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
5. STEP 5. Measure the resistance at ABS/TCL-ECU connector A-03. 
   1. Disconnect the connector A-03, and connect special tool MB991997 to the wiring harness-side connector.
      NOTE: DO NOT connect special tool MB991997 to the ABS/TCL-ECU.
   2. Measure the resistance between terminal 47 and ground. It should be 2 ohms or less.

   Q: Is the measured resistance 2 ohms or less? 

   YES :  Go to  Step 7.

   NO :  Go to Step 6.

   Fig 5: Measuring Resistance Between Terminal No. 47 & Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
6. STEP 6. Check ABS/TCL-ECU connector A-03 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is ABS/TCL-ECU connector A-03 damaged? 

   YES :  Repair or replace the damaged component(s). Refer to HARNESS CONNECTOR INSPECTION . Then go to  Step 8.

   NO :  An open circuit may be present in the ground circuit. Repair the wiring harness between ABS/TCL-ECU connector A-03 terminal 1 and the body ground. Then go to  Step 8.

   Fig 6: Identifying Connector A-03 Terminals

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. Recheck for 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.

   Check again if the DTC is set.

   1. Turn the ignition switch to the "ON" position.
   2. Erase the DTC.
   3. Turn the ignition switch to the "LOCK" (OFF) position.
   4. Turn the ignition switch to the "ON" position.
   5. Check if the DTC is set.
   6. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is DTC C1271 set? 

   YES :  Replace the hydraulic unit (integrated with ABS/TCL-ECU). Then go to Step 8.

   NO :  It can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTION .

   Fig 7: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
8. STEP 8. Recheck for 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.

   Check again if the DTC is set.

   1. Turn the ignition switch to the "ON" position.
   2. Erase the DTC.
   3. Turn the ignition switch to the "LOCK" (OFF) position.
   4. Turn the ignition switch to the "ON" position.
   5. Check if the DTC is set.
   6. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is DTC C1271 set? 

   YES :  Go to  Step 1.

   NO :  The procedure is complete.

   Fig 8: Connecting Scan Tool To Data Link Connector

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.