Code No. P1777: Malfunction of Stepper Motor
DIAGNOSTIC FUNCTION
JUDGEMENT CRITERIA
PROBABLE CAUSES
- Malfunction of valve body assembly (Faulty stepper motor)
- Damaged wiring harness and connectors
- Malfunction of CVT-ECU
DIAGNOSTIC PROCEDURE |
STEP 1. Check for open circuit and short to earth in SPM1, SPM2, SPM3, SPM4 line between the CVT-ECU connector and the CVT assembly (stepper motor) |
| Between CVT-ECU connector and body earth |
| OK: Resistance value is approximately 15 Ω. |
Q.
Is the check result normal?
|
 Go to Step 3. |
|
 Go to Step 2. |
|
STEP 2. Check for open circuit and short to earth in SPM1, SPM2, SPM3, SPM4 line between CVT-ECU connector and the CVT assembly (stepper motor) |
| 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 earth. |
Q.
Is the check result normal?
|
| Replace the valve body assembly. |
|
| Repair the connector(s) or wiring harness. |
|
STEP 3. Symptom recheck after erasing diagnosis code |
Q.
Is the check result normal?
|
| Intermittent malfunction |
|
| Replace CVT-ECU. |
|