Toyota Tundra. Manual — part 2823

Fig. 69: Identifying 1-2 Shift Valve
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

DTC DETECTION CONDITION TABLE

HINT:



Gear positions in the event of a solenoid valve mechanical problem:

GEAR SHIFT POSITIONS TABLE



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

DTC

Code

DTC Detection Condition

Trouble Area

P0781

When 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 up or
stuck (1-2 shift valve)



Shift solenoid valve SLT
remains open or closed



Automatic transmission
(clutch, brake, gear, etc.)

ECM gear shift command

1st 2nd 3rd 4th 5th 6th

Actual gear position under malfunction 1st 1st 3rd 3rd

(1) (1)

(1)

Neutral

2009 Toyota Tundra

2009 TRANSMISSION AB60F Automatic Transaxle - Tundra

shown in the table below.

GEAR SHIFT POSITIONS TABLE

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.

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

MONITOR STRATEGY TABLE

TYPICAL ENABLING CONDITIONS

ALL

TYPICAL ENABLING CONDITIONS TABLE

Gear position under normal conditions

1st 2nd 3rd 4th 5th 6th

Actual gear position under fail-safe mode

(1) (1)

3rd 3rd 3rd 3rd

(1)

Under engine braking, downshifting to 1st or 2nd gear is prohibited.

Related DTCs

P0781: Valve body/Rationality check

Required sensors/Components

Valve body, Automatic transmission assembly

Frequency of operation

Continuous

Duration

Condition (A) and (B)
0.4 sec.
Condition (C)
3 sec.
Condition (D)
1 sec.

MIL operation

2 driving cycles

Sequence of operation

None

The monitor will run whenever the following DTCs
are not stored

P0500 (VSS)

P0748 - P0798 (Trans solenoid (range))

Turbine speed sensor circuit

Not circuit malfunction

Output speed sensor circuit

Not circuit malfunction

Shift solenoid valve S1 circuit

Not circuit malfunction

2009 Toyota Tundra

2009 TRANSMISSION AB60F Automatic Transaxle - Tundra

TYPICAL ENABLING CONDITIONS TABLE

Condition (A)

TYPICAL ENABLING CONDITIONS TABLE

Condition (B)

TYPICAL ENABLING CONDITIONS TABLE

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

KCS sensor circuit

Not circuit malfunction

ETCS (Electric Throttle Control System)

Not system down

Transmission position

D

Duration time from shifting N to D

4 sec. 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

Transfer position

HIGH*

HINT:
*: Following conditions met

Vehicle speed sensor 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

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

9% or more at 2000 RPM (Conditions vary with

engine speed)

ECM selected gear

4th

Vehicle speed

2 km/h (1.2 MPH) or more

Throttle valve opening angle

9% or more at 2000 RPM (Conditions vary with

engine speed)

2009 Toyota Tundra

2009 TRANSMISSION AB60F Automatic Transaxle - Tundra

Condition (C)

TYPICAL ENABLING CONDITIONS TABLE

Condition (D)

TYPICAL ENABLING CONDITIONS TABLE

TYPICAL MALFUNCTION THRESHOLDS

When both of the following conditions are met: Condition (A), and Condition (B), (C) or (D)

Condition (A)

TYPICAL MALFUNCTION THRESHOLDS TABLE

Condition (B)

TYPICAL MALFUNCTION THRESHOLDS TABLE

Condition (C)

TYPICAL MALFUNCTION THRESHOLDS TABLE

Condition (D)

TYPICAL MALFUNCTION THRESHOLDS TABLE

INSPECTION PROCEDURE

1. CHECK DTC OUTPUT (IN ADDITION TO DTC P0781)

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)

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)

Turbine speed/Output speed (NT/NO)

3.11 or more, and 7.58 or less (This means actual gear is 1st)

Turbine speed/Output speed (NT/NO)

1.24 or more, and 1.49 or less (This means actual gear is 3rd)

Turbine speed - Output speed x 4th gear ratio (NT - NO x 4th
gear ratio)

1000 RPM or more

Turbine speed - Output speed x 5th gear ratio (NT - NO x 5th
gear ratio)

1000 RPM or more

2009 Toyota Tundra

2009 TRANSMISSION AB60F Automatic Transaxle - Tundra