P0778
DTC P0778: Malfunction of Secondary Pressure Solenoid ValveSOLENOID VALVE SYSTEM CIRCUIT
Refer to DTC P0740. 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)
Logic Flow Charts (Monitor Sequence):
DTC SET CONDITIONS
Judgement Criteria
^ Monitored current [target current: 750 mA or more]: 400 mA or less. (5 seconds)
^ Secondary pressure solenoid valve circuit: ground short. (1 second)
OBD-II DRIVE CYCLE PATTERN
All the conditions below continue for 6 seconds.
^ Transmission range switch: D
^ Vehicle speed: 10 km/h (6.2 mph) or more
^ Throttle position: 1/8 or more
^ Engine speed: 450 r/min or more
^ Transmission fluid temperature: 20°C (68°F) or more.
^ Transmission fluid temperature: 99°C (210°F) 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?
YES: Intermittent malfunction
NO: 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?
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
Q: Is the check result normal?
YES: Go to Step 5.
NO: Replace the valve body assembly.
STEP 5. Symptom recheck after erasing diagnosis code
Q: Is the check result normal?
YES: Intermittent malfunction
NO: Replace TCM.