DTC P0811
DTC P0811: Excessive Clutch A Slippage
General Description
When running at 44 mph (70 km/h) or more, the line pressure is supplied to the clutch piston in response to a request for engagement of the over drive clutch from the powertrain control module (PCM) to cause the clutch to be engaged and the input shaft and the over drive gear rotate together to transmit the driving force. The hydraulic pressure to the clutch is supplied from the ATF pump -> regulator valve -> shift valve -> clutch piston. (Failure in the clutch piston in the supply paths above is detected by failure detection of each shift solenoid valve.) The PCM calculates the difference between the input revolution speed (Engine speed) to the over drive clutch and the output revolution speed (Traction motor speed) and detects a malfunction of the hydraulic pressure supply system or the clutch and stores a DTC when the difference in the revolution speed is more than the prescribed value when engagement of the over drive clutch is requested.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 500 milliseconds or more |
| DTC Type | Two drive cycles, MIL off, shift position indicator blinks |
Enable Conditions
| Condition | Minimum | Maximum | |
|---|---|---|---|
| Vehicle speed [VEHICLE SPEED] |
44 mph (70 km/h) | - | |
| 12 volt battery voltage [BATTERY VOLTAGE] | 11 V | - | |
| Over drive clutch | ON | ||
| State of the vehicle | Engine driving mode | ||
[ ]: HDS Parameter
Malfunction Threshold
When the difference between the input revolution speed (Engine speed) to the over drive clutch and the output revolution speed (Traction motor speed) is 100 RPM or more continuously for 500 milliseconds or more when engagement of the over drive clutch is requested.
Possible Cause
- Shift valve A stuck
- Shift valve B stuck
- Shift solenoid valve A failure
- Shift solenoid valve B failure
- Over drive clutch failure
Confirmation Procedure
Operating Condition
- Enter the maintenance mode, then start the engine. Hold the engine speed [ENGINE SPEED] at 3, 000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.
- Drive the vehicle at a steady speed of 44 mph (70 km/h) or more for at least 10 seconds with engine drive mode.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
None.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the shift position indicator blinks and a Confirmed DTC and the freeze data are stored. The MIL does not come on.
Conditions for clearing the DTC
The shift position indicator comes off by turning the vehicle to the OFF (LOCK) mode. The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.