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Home >> Mitsubishi >> 2017 >> Lancer SE >> Repair and Diagnosis >> External Pages >> Different car >> Section 36 (Continuously Variable Transaxle (CVT) Diagnosis & On-Vehicle Service - With Diagnostics - Lancer) >> Diagnosis >> Diagnostic Trouble Code Procedures >> DTC P1777: Malfunction of Stepper Motor >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2015 Mitsubishi Lancer. However, it is still accessible from the selected car via links, so may be relevant.
  1. STEP 1. Check the following connector: 
    • B-08 CVT assembly connector
    • C-40 TCM connector

    Check the terminals for a contact status problem and internal short circuit.

    Q: Is the check result normal? 

    1. YES:  Go to Step 2.
    2. NO:  Repair the defective connector.
  2. STEP 2. Check for open circuit and short to ground in the wiring harness between the TCM connector and the stepper motor. 
    • Between TCM connector (terminal No. 40) and body ground
    • Between TCM connector (terminal No. 41) and body ground
    • Between TCM connector (terminal No. 51) and body ground
    • Between TCM connector (terminal No. 52) and body ground

      OK: Resistance value is approximately 15 Ω. 

    Q: Is the check result normal? 

    1. YES:  Go to  Step 4.
    2. NO:  Go to Step 3.
  3. STEP 3. Check for open circuit and short to ground in the wiring harness between TCM and the stepper motor 
    • Between C-40 TCM connector (terminal No. 40) and B-08 CVT assembly connector (terminal No. 8)
    • Between C-40 TCM connector (terminal No. 41) and B-08 CVT assembly connector (terminal No. 9)
    • Between C-40 TCM connector (terminal No. 51) and B-08 CVT assembly connector (terminal No. 10)
    • Between C-40 TCM connector (terminal No. 52) and B-08 CVT assembly connector (terminal No. 11)

    Check that there is no continuity in both sides of the connectors and that no short circuit is present between the connectors and the body ground.

    Q: Is the check result normal? 

    1. YES:  Replace the valve body assembly.
    2. NO:  Repair the wiring harness.
  4. STEP 4. Symptom recheck after erasing diagnostic trouble code 

    Q: Is the check result normal? 

    1. YES:  Intermittent malfunction
    2. NO:  Replace TCM.