P0781

DTC P0781 11-2 Shift (1-2 Shift Valve)

DESCRIPTION
The 1-2 shift valve performs shifting to 1st gear and other gears.

P0781:

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





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.





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.

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, and the 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





TYPICAL ENABLING CONDITIONS








TYPICAL MALFUNCTION THRESHOLDS





INSPECTION PROCEDURE

Step 1(Part 1):

Steps 1(Part 2)-2(Part 1):

Steps 2(Part 2)-3(Part 1):

Steps 3(Part 2)-4: