Toyota Tundra (2015 year). Manual — part 460
Last Modified: 9-16-2014
6.6 C
Doc ID: RM000000XP10BKX
Model Year: 2015
Model: Tundra
Prod Date Range: [08/2014 - ]
Title: A760F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0781; 1-2 Shift (1-2 Shift
Valve); 2015 MY Tundra [08/2014 - ]
DTC
P0781
1-2 Shift (1-2 Shift Valve)
DESCRIPTION
The 1-2 shift valve performs shifting to 1st gear and other gears. When shifting to 2nd and 4th gears is
impossible, or when the ECM directs the transmission to switch to 5th or 6th gear and the engine overruns
(clutch slips), this DTC is stored.
DTC
CODE
DTC DETECTION CONDITION
TROUBLE AREA
P0781
Conditions (a) and (b), or (a) and (c) are met (2-trip
detection logic):
(a) When the ECM directs the transmission to switch to
2nd gear, the actual gear is shifted to 1st.
(b) When the ECM directs the transmission to switch to
4th gear, the actual gear is shifted to 3rd.
(c) When the ECM directs the transmission to switch to 5th
gear, the engine overruns (clutch slips).
Valve body is blocked or stuck
(1-2 shift valve)
Shift solenoid valve SLT
remains open or closed
Automatic transmission (clutch,
brake, gear, etc.)
HINT:
1st
2nd
3rd
4th
5th
6th
Actual gear position under malfunction
1st
1st
3rd
3rd
N*
N*
N*: Neutral
Gear position during fail-safe operation:
If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear
positions as shown in the table below.
Gear position under normal conditions
1st
2nd
3rd
4th
5th
6th
Actual gear position under fail-safe mode
1st*
1st*
3rd
3rd
3rd
3rd
HINT:
1st*: Under engine braking, downshifting to 1st or 2nd gear is prohibited.
MONITOR DESCRIPTION
This DTC indicates that the 1-2 shift valve in the valve body is locked in the direction the spring compresses.
The ECM commands gear shifts by turning the shift solenoid valves ON/OFF and switching oil pressure to the
valves in the valve body.
A760F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISS...
The ECM calculates the "actual" transmission gear by comparing the signals from the input speed sensor (NT) and
the output speed sensor (SP2). The ECM can detect many mechanical problems in the shift solenoids, valve body,
transmission clutches, brakes, and gears. If the ECM detects that the actual gear position and the commanded
gear position are different, it will illuminate the MIL and store the DTC.
MONITOR STRATEGY
Related DTCs
P0781: Valve body / Functional check
Required sensors/Components
Valve body, Automatic transmission assembly
Duration
Condition (A) and (B)
0.4 seconds
Condition (C)
3 seconds
Condition (D)
1 second
MIL operation
2 driving cycles
TYPICAL ENABLING CONDITIONS
All
The monitor will run whenever the following DTCs
are not present
P0717 (Turbine speed sensor circuit)
P0500 (Output speed sensor circuit)
P0327, P0328, P032C, P032D, P0332, P0333, P033C, P033D
(KCS sensor circuit)
Shift solenoid valve S1 circuit
Not circuit malfunction
Shift solenoid valve S2 circuit
Not circuit malfunction
Shift solenoid valve S3 circuit
Not circuit malfunction
Shift solenoid valve S4 circuit
Not circuit malfunction
Shift solenoid valve SR circuit
Not circuit malfunction
Shift solenoid valve SL1 circuit
Not circuit malfunction
Shift solenoid valve SL2 circuit
Not circuit malfunction
ECT (Engine Coolant Temperature) sensor circuit
Not circuit malfunction
ETCS (Electric Throttle Control System)
Not system down
Transmission position
"D"
Duration time from shifting "N" to "D"
4 seconds or more
ECT
40°C (104°F) or higher
Spark advance from max. retard timing by KCS
control
0° crankshaft angle or more
Engine
Starting
A760F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISS...
Transfer position
HIGH*
HINT:
*: Following conditions are met
Vehicle speed sensor "A" circuit
Not circuit malfunction
Output shaft speed sensor circuit
Not circuit malfunction
Transfer output speed
143 rpm or more
Transfer input speed / Transfer output speed (NO / NOtf)
0.9 or more, and less than 1.1
Condition (A)
ECM selected gear
2nd
Vehicle speed
2 km/h (1.2 mph) or more
Output speed
2nd → 1st down-shift point or more
Throttle valve opening angle
6.6% or more at 2000 rpm
(Conditions vary with engine speed)
Calculated load value
7.75% or more (A/C off)
7.75% or more (A/C on)
Input speed/output speed (NT/NO)
NT: Input (Turbine) speed
NO: Internal counter shaft speed
3.30 to 7.50
or
1.91 to 2.35
or
1.28 to 1.53
or
0.93 to 1.07
or
0.65 to 0.79
or
0.51 to 0.65
Condition (B)
ECM selected gear
4th
Vehicle speed
2 km/h (1.2 mph) or more
Throttle valve opening angle
6.6% or more at 2000 rpm
(Conditions vary with engine speed)
Calculated load value
7.75% or more (A/C off)
7.75% or more (A/C on)
Input speed/output speed (NT/NO)
NT: Input (Turbine) speed
NO: Internal counter shaft speed
3.30 to 7.50
or
1.91 to 2.35
or
1.28 to 1.53
or
A760F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISS...
0.93 to 1.07
or
0.65 to 0.79
or
0.51 to 0.65
Condition (C)
Current ECM selected gear
5th
Last ECM selected gear
4th
Vehicle speed (During transition from 4th to 5th gear)
Less than 100 km/h (62.2 mph)
Condition (D)
ECM selected gear
5th
Engine speed -Turbine speed (NE - NT) (After transition to 5th gear)
150 rpm or less
Vehicle speed (After transition to 5th gear)
Less than 100 km/h (62.2 mph)
TYPICAL MALFUNCTION THRESHOLDS
Turbine speed / Output speed (NT / NO)
3.30 or more, and 7.50 or less
(This means actual gear is 1st)
Condition (B)
Turbine speed / Output speed (NT / NO)
1.28 or more, and 1.53 or less
(This means actual gear is 3rd)
Condition (C)
Turbine speed - Output speed x 4th gear ratio
(NT - NO x 4th gear ratio)
1000 rpm or more
Condition (D)
Turbine speed - Output speed x 5th gear ratio
(NT - NO x 5th gear ratio)
1000 rpm or more
INSPECTION PROCEDURE
NOTICE:
Perform the universal trip to clear permanent DTCs
.
PROCEDURE
A760F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISS...
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