P0778

DTC P0778: Malfunction of Secondary Pressure Solenoid Valve

SOLENOID VALVE SYSTEM CIRCUIT

Refer to P0740.

DIAGNOSTIC FUNCTION

TCM determines malfunction by detecting the abnormality in the secondary pressure solenoid valve.

DESCRIPTIONS OF MONITOR METHODS

- Specified amount of current is not flown to the secondary pressure solenoid valve because of an open or short circuit.

MONITOR EXECUTION

- Continuous

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)

- P0741: Abnormality in lockup function
- P0746: Abnormality in hydraulic control system function
- P0841: Abnormality in line pressure sensor function
- P0868: Secondary pressure drop
Sensor (The sensor below is determined to be normal)

- Not applicable

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Judgment Criteria

- Monitored current [target current: 750 mA or more]: 400 mA or less. (5 seconds)
- Monitored current: 1.34 A or more. (1 second)

OBD-II DRIVE CYCLE PATTERN

Ignition switch : ON (start the engine and keep it for 10 seconds or more)

PROBABLE CAUSES

- Malfunction of valve body assembly (Faulty secondary pressure solenoid valve)
- Damaged wiring harness and connectors
- Malfunction of TCM

DIAGNOSIS

STEP 1. M.U.T.-III data list

- Item 35: Secondary PRS. SOL. output current
- Item 34: Secondary PRS. SOL. monitor current

OK: Check if the output current and monitoring current differ largely.


Q. Is the check result normal?

YES Intermittent malfunction
NO Go to Step 2.
STEP 2. Check the following connector:

- C-41 TCM connector
- A-10 Intermediate connector
- B-08 CVT assembly connector

Check the terminals for a contact status problem and internal short circuit.

Q. Is the check result normal?

YES Go to Step 3.
NO Repair the defective connector.
STEP 3. Check for open circuit and short to ground in the wiring harness between the TCM connector and the CVT assembly connector.

Between C-41 TCM connector (terminal No.2) and B-08 CVT assembly connector (terminal No.2)

Q. Is the check result normal?

YES Go to Step 4.
NO Repair the wiring harness.
STEP 4. Secondary pressure solenoid valve single unit check

Refer to Testing and Inspection.

Q. Is the check result normal?

YES Go to Step 5.
NO Replace the valve body assembly.
STEP 5. Symptom recheck after erasing diagnostic trouble code

Q. Is the check result normal?

YES Intermittent malfunction
NO Replace TCM.