Dtc P0973 Shift Solenoid A Control Circuit Low (Shift Solenoid Valve S1)

Drivetrain. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25
A750F Automatic Transmission Transaxle. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25

DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE S1)

CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)

INSPECT SHIFT SOLENOID VALVE S1

DTC P0973 Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1)

DTC P0974 Shift Solenoid "A" Control Circuit High (Shift Solenoid Valve S1)


DESCRIPTION

Shifting from 1st to 5th is performed in combination with the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2 and SR, which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated smoothly. In case of an open or short circuit, the ECM stops sending current to the circuit. For details, refer to the fail-safe chart (HILUX_TGN26 RM000000O8L0MKX.html).

DTC Code
DTC Detection Condition
Trouble Area
P0973
The ECM detects a short in the solenoid valve S1 circuit 2 times when solenoid valve S1 is operated (1-trip detection logic).
  1. Short in shift solenoid valve S1 circuit
  2. Shift solenoid valve S1
  3. ECM
P0974
The ECM detects an open in the solenoid valve S1 circuit 2 times when solenoid valve S1 is not operated (1-trip detection logic).
  1. Open in shift solenoid valve S1 circuit
  2. Shift solenoid valve S1
  3. ECM

MONITOR DESCRIPTION

These DTCs indicate an open or short in the shift solenoid valve S1 circuit. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem, illuminates the MIL and stores the DTC. When the shift solenoid valve S1 is on, if its resistance is 8 Ω or less, the ECM determines there is a short in the shift solenoid valve S1 circuit.
When the shift solenoid valve S1 is off, if its resistance is 100 kΩ or higher, the ECM determines there is an open in the shift solenoid valve S1 circuit (HILUX_TGN26 RM000000O8L0MKX.html).

WIRING DIAGRAM


Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.A750F Automatic Transmission Transaxle.Automatic Transmission System (For 1Gr-Fe).
Dtc
  P0973  Shift Solenoid A Control Circuit Low (Shift Solenoid Valve S1)


INSPECTION PROCEDURE


HINT:
The shift solenoid valve S1 turns ON/OFF normally when the shift lever is in D.

ECM gear shift command
1st
2nd
3rd
4th
5th
Shift solenoid valve S1
ON
ON
OFF
OFF
OFF
1.INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE S1)


    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.A750F Automatic Transmission Transaxle.Automatic Transmission System (For 1Gr-Fe).
Dtc
  P0973  Shift Solenoid A Control Circuit Low (Shift Solenoid Valve S1)
  1. Disconnect the transmission wire connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    Condition
    Specified Condition
    8 (S1) - Body ground
    20°C (68°F)
    11 to 15 Ω
    Text in Illustration
    *a
    Component without harness connected
    (Transmission Wire)


NG
Go to step 3
OK


2.CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)


    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.A750F Automatic Transmission Transaxle.Automatic Transmission System (For 1Gr-Fe).
Dtc
  P0973  Shift Solenoid A Control Circuit Low (Shift Solenoid Valve S1)
  1. Disconnect the ECM connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    Condition
    Specified Condition
    C130-11 (S1) - Body ground
    20°C (68°F)
    11 to 15 Ω
    Text in Illustration
    *a
    Rear view of wire harness connector
    (to ECM)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (HILUX_TGN26 RM000000VW202SX.html)

3.INSPECT SHIFT SOLENOID VALVE S1


    Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.A750F Automatic Transmission Transaxle.Automatic Transmission System (For 1Gr-Fe).
Dtc
  P0973  Shift Solenoid A Control Circuit Low (Shift Solenoid Valve S1)
  1. Remove shift solenoid valve S1.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    Condition
    Specified Condition
    Shift solenoid valve S1 connector terminal - Shift solenoid valve S1 body
    20°C (68°F)
    11 to 15 Ω
  1. Apply 12 V battery voltage to the shift solenoid valve and check that the valve moves and makes an operating noise.

    OK:
    Measurement Condition
    Specified Condition
    1. Battery positive (+) → Shift solenoid valve S1 connector
    2. Battery negative (-) → Shift solenoid valve S1 body
    Valve moves and makes operating noise
Text in Illustration
*a
Component without harness connected
(Shift Solenoid Valve S1)


NG
REPLACE SHIFT SOLENOID VALVE S1 (HILUX_TGN26 RM0000013FG02KX_01_0007.html)
OK

REPAIR OR REPLACE TRANSMISSION WIRE (HILUX_TGN26 RM0000013C1047X.html)