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DTC P0778: Malfunction of Secondary Pressure Solenoid Valve

SOLENOID VALVE SYSTEM CIRCUIT

Refer to

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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

DIAGNOSTIC PROCEDURE

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?

	Intermittent malfunction

	Go to Step 2.

STEP 2. Check the following connector:

C-41 TCM connector
B-08 CVT assembly connector

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

Q. Is the check result normal?

	Go to Step 3.

	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?

	Go to Step 4.

	Repair the wiring harness.

STEP 4. Secondary pressure solenoid valve single unit check

Refer to

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Q. Is the check result normal?

	Go to Step 5.

	Replace the valve body assembly.

STEP 5. Symptom recheck after erasing diagnosis code

Q. Is the check result normal?

	Intermittent malfunction

	Replace TCM.