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. (Refer to Troubleshooting.) CAN Bus Diagnostics Chart After repairing the CAN bus line, go to Step 2.

STEP 2. Check the fluid.

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

STEP 3. 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 : Intermittent malfunction. (Refer to How to Cope with Intermittent Malfunction.) Troubleshooting Contents