DTC P1777: Malfunction of Stepper Motor: Diagnosis

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

STEP 1. Check the following connector:
- B-120 CVT assembly connector
- C-130 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.
STEP 2. Check for open circuit and short to ground in the wiring harness between the TCM connector and the stepper motor.
- Between C-130 TCM connector (terminal No.40) and body ground
- Between C-130 TCM connector (terminal No.41) and body ground
- Between C-130 TCM connector (terminal No.51) and body ground
- Between C-130 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.
STEP 3. Check for open circuit and short to ground in the wiring harness between TCM and the stepper motor
- Between C-130 TCM connector (terminal No.40) and B-120 CVT assembly connector (terminal No.8)
- Between C-130 TCM connector (terminal No.41) and B-120 CVT assembly connector (terminal No.9)
- Between C-130 TCM connector (terminal No.51) and B-120 CVT assembly connector (terminal No.10)
- Between C-130 TCM connector (terminal No.52) and B-120 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.
STEP 4. Symptom recheck after erasing diagnostic trouble code
Q: Is the check result normal?
1. YES: Intermittent malfunction
2. NO: Replace TCM.