P0777

DTC P0777: Clutch Cooling Flow Solenoid System (Stuck)

CAUTION
^ If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

DIAGNOSTIC FUNCTION
TC-SST-ECU checks that the clutch cooling flow solenoid is normal.

DESCRIPTIONS OF MONITOR METHODS
The clutch cooling flow solenoid is determined to be seized.

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)
^ P0776: Clutch cooling flow solenoid system (Drive current range out)
^ P0964: Clutch cooling flow solenoid system (Open circuit)
^ P0965: Clutch cooling flow solenoid system (Overvoltage)
^ P0966: Clutch cooling flow solenoid system (Short to ground)
^ P0967: Clutch cooling flow solenoid system (Short to power supply)

Sensor (The sensor below is determined to be normal)
^ Not applicable

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Check Conditions
^ Voltage of battery: 8 V or more.
^ Voltage of battery: 16.5 V or less.
^ Engine speed: 650 r/min or more.
^ Time since above engine condition: 1.5 seconds or more.
^ Clutch 1 target pressure: 380 hPa or more.
^ Clutch 2 target pressure: 380 hPa or more.

JUDGMENT CRITERIA
^ Clutch 1 pressure: 100 hPa or less, and clutch 2 pressure: 100 hPa or less. (8 seconds)

OBD-II DRIVE CYCLE PATTERN
The Clutch 1 pressure and clutch 2 pressure remain 100 hPa or more for 8 seconds.

PROBABLE CAUSES
^ Malfunction of TC-SST-ECU
^ Malfunction of clutch cooling flow solenoid
^ Insufficient fluid level
^ Improper installation of mechatronic assembly

DIAGNOSTIC PROCEDURE

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 2.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.

STEP 2. Check whether the DTC is reset.
1) Erase the DTC.
2) Carry out the Item No. 3 (Teach-In): Line pressure Test. Teach-In Reference Table
3) With the engine idle status, check that the DTC is reset.
Q: Is the DTC No. P0777 restored? or Is the line pressure test of Teach-in not completed normally ("No" is displayed in the Data list No.101: Normal End)?
YES: Go to Step 3.
NO: Intermittent malfunction.

STEP 3. Check the fluid.
Q: Is the fluid level proper?
YES: Go to Step 4
NO: Add the fluid.

STEP 4. Check the installation status of the mechatronic assembly.
Q: Is the mechatronic assembly installed correctly?
YES: Go to Step 5
NO: Install the mechatronic assembly correctly.

STEP 5. Check whether the DTC is reset.
1) Erase the DTC.
2) With the engine idle status, check that the DTC is reset.
Q: Is DTC No. P0777 set?
YES: Replace the mechatronic assembly. Then, go to Step 6.
NO: Intermittent malfunction.

STEP 6. Check whether the DTC is reset.
1) Erase the DTC.
2) With the engine idle status, check that the DTC is reset.
Q: Is DTC No. P0777 set?
YES: Replace the transaxle assembly.
NO: This diagnosis is complete.