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. 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. (Refer to Removal and Replacement.)
NO Intermittent malfunction. How to Cope With Intermittent Malfunctions.)