P1778

P1778 STEP MOTOR

Description

- Step motor changes step by turning 4 coils ON or OFF according to signal from TCM.
- By changing step, step motor controls outward flow and inward flow of line pressure to primary pulley, determines the primary pulley position, and controls gear ratio.
- This DTC is not caused by an electrical malfunction (circuit open or short) but is caused by a mechanical malfunction (control valve clogging, solenoid valve sticking, and others).


DTC Logic


DTC DETECTION LOGIC







DTC CONFIRMATION PROCEDURE


CAUTION:
- Always drive vehicle at a safe speed.
- Before starting "DTC confirmation procedure", check primary pulley speed and vehicle speed.
- It is fixed in high speed range. Go to P0715.

1. PRECONDITIONING

Immediately after performing any "DTC CONFIRMATION PROCEDURE", always turn ignition switch OFF.
Then wait at least 10 seconds before performing the next test.
- GO TO 2.

2. PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT
1.Select "Data Monitor" in "TRANSMISSION".
2.Select "RANGE", "ATF TEMP SEN", "ACC PEDAL OPEN", "PRI SPEED" and "VEHICLE SPEED".
3.Drive the vehicle.
4.Maintain the following conditions for 5 seconds or more.

RANGE :D
ATF TEMP SEN :2.03 - 0.16 V
ACC PEDAL OPEN :More than 1.0/8
PRI SPEED :More than 1,000 rpm
VEHICLE SPEED :More than 10 km/h (7 MPH)

5.Stop the vehicle.
6.Select "Self Diagnostic Results" in "TRANSMISSION".
With GST
Follow the procedure "With CONSULT".
Is "P1778" detected?
YES- Go to .
NO- INSPECTION END


Diagnosis Procedure


1. CHECK STEP MOTOR SYSTEM

Check step motor system. P1777.
Is the inspection result normal?
YES- GO TO 2.
NO- Repair or replace damaged parts.

2. CHECK PRIMARY SPEED SENSOR SYSTEM

Check primary speed sensor system. P0715.
Is the inspection result normal?
YES- GO TO 3.
NO- Repair or replace damaged parts.

3. CHECK SECONDARY SPEED SENSOR SYSTEM

Check secondary speed sensor system. P0720.
Is the inspection result normal?
YES- GO TO 4.
NO- Repair or replace damaged parts.

4. CHECK INTERMITTENT INCIDENT

Intermittent Incident.
Is the inspection result normal?
YES- Replace transaxle assembly. Exploded View.
NO- Repair or replace damaged parts.