P0778

P0778 PRESSURE CONTROL SOLENOID B





Description
- The secondary pressure solenoid valve regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the TCM.




CONSULT-III Reference Value









On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P0778" with CONSULT-III is detected under the following conditions.
- TCM detects an improper voltage drop when it tries to operate the solenoid valve.
- When TCM compares target value with monitor value and detects an irregularity.




Possible Cause
- Harness or connectors
(Solenoid circuit is open or shorted.)
- Secondary pressure solenoid valve




DTC Confirmation Procedure

NOTE:
If "DTC Confirmation Procedure" has been previously performed, always turn ignition switch OFF and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.

WITH CONSULT-III
1. Turn ignition switch ON.
2. Select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
3. Start engine and wait at least 5 seconds.
4. If DTC is detected, go to SEE Diagnosis Procedure.

WITH GST
Follow the procedure "WITH CONSULT-III".




Wiring Diagram - CVT - SECPSV






TCM TERMINALS AND REFERENCE VALUES
CVT Trouble Diagnosis.




Diagnosis Procedure
1. CHECK INPUT SIGNAL
With CONSULT-III
1. Start engine.
2. Select "MAIN SIGNALS" in "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
3. Read out the value of "ISOLT3".






Without CONSULT-III
1. Start engine.
2. Check voltage between TCM connector terminal and ground.






3. Turn ignition switch OFF.
4. Disconnect TCM connector.
5. Check if there is continuity between connector terminal and ground.
OK or NG
OK - GO TO 5.
NG - GO TO 2.
2.CHECK SECONDARY PRESSURE SOLENOID VALVE CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect TCM connector.





3. Check resistance between TCM connector terminal and ground.






OK or NG
OK - GO TO 5.
NG - GO TO 3.
3.CHECK VALVE RESISTANCE
1. Turn ignition switch OFF.
2. Disconnect CVT unit harness connector.





3. Check resistance between CVT unit harness connector terminal and ground.






OK or NG
OK - GO TO 4.
NG - Repair or replace damaged parts.
4.CHECK HARNESS BETWEEN TCM AND SECONDARY PRESSURE SOLENOID VALVE
1. Turn ignition switch OFF.
2. Disconnect TCM connector (A) and CVT unit harness connector (B).





3. Check continuity between TCM connector (A) terminal and CVT unit harness connector (B) terminal.






4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK - GO TO 5.
NG - Repair or replace damaged parts.
5.CHECK DTC
Perform SEE DTC Confirmation Procedure.
OK or NG
OK - INSPECTION END
NG - GO TO 6.
6.CHECK TCM
1. Check TCM input/output signals. CVT Trouble Diagnosis.
2. If NG, re-check TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK - INSPECTION END
NG - 1. Repair or replace damaged parts.
2. Replace the transaxle assembly. Removal and Installation(MR20DE), Removal and Installation (QR25DE).




Component Inspection

SECONDARY PRESSURE SOLENOID VALVE
1. Turn ignition switch OFF.
2. Disconnect CVT unit harness connector.





3. Check resistance between CVT unit harness connector terminal and ground.






4. If NG, replace the transaxle assembly. Removal and Installation (MR20DE), Removal and Installation (QR25DE).