P1778

P1778 STEP MOTOR

Description

- The step motor changes the step by turning 4 coils ON/OFF according to the signal from TCM. As a result, the flow of line pressure to primary pulley is changed and pulley ratio is controlled.
- This diagnosis item is detected when the electrical system is OK, but the mechanical system is NG.
- This diagnosis item is detected when the state of the changing of the speed mechanism in the unit does not operate normally.


DTC Logic


DTC DETECTION LOGIC







DTC CONFIRMATION PROCEDURE


CAUTION:
- Always drive vehicle at a safe speed.
- Before starting "DTC CONFIRMATION PROCEDURE", confirm "Hi" or "Mid" or "Low" fixation by
"PRI SPEED" and "VEHICLE SPEED" on "Data Monitor".
- If hi-geared fixation occurred, go to Diagnosis Procedure (see below).
NOTE:
Immediately after performing any "DTC CONFIRMATION PROCEDURE", always turn ignition switch OFF.
Then wait at least 10 seconds before performing the next test.

1. CHECK DTC DETECTION

With CONSULT
1.Turn ignition switch ON.
2.Select "Data Monitor" in "TRANSMISSION".
3.Make sure that output voltage of CVT fluid temperature sensor is within the range specified below.





4.Start engine and maintain the following conditions for at least 30 consecutive seconds.





With GST
Follow the procedure "With CONSULT".
Is "P1778" detected?
YES- Go to Diagnosis Procedure (see below).
NO- Check intermittent incident. Intermittent Incident.


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. Transmission Assembly (2WD) or TM211, "AWD : Removal and Installation" (AWD).
NO- Repair or replace damaged parts.