Toyota Tundra Service Manual: Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1) (P0973,P0974)

Toyota Tundra Service Manual / Engine, Hybrid System / A760e Automatic Transmission / Transaxle / Automatic Transmission System / Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1) (P0973,P0974)

DESCRIPTION

Shifting from 1st to 6th is performed in combination with ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Also, the ECM stops sending current to the open or short-circuited solenoid (See page ).

DTC Code

DTC Detection Condition

Trouble Area

P0973

ECM detects a short in the solenoid valve S1 circuit 2 times when solenoid valve S1 is operated (1-trip detection logic).

  • Short in shift solenoid valve S1 circuit
  • Shift solenoid valve S1
  • ECM

P0974

ECM detects an open in the solenoid valve S1 circuit 2 times when solenoid valve S1 is not operated (1-trip detection logic).

  • Open in shift solenoid valve S1 circuit
  • Shift solenoid valve S1
  • 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 more, the ECM determines there is an open in the shift solenoid valve S1 circuit (See page ).

MONITOR STRATEGY

Related DTCs

P0973: Shift solenoid valve S1/Range check (Low resistance)

P0974: Shift solenoid valve S1/Range check (High resistance)

Required sensors/Components

Shift solenoid valve S1

Frequency of operation

Continuous

Duration

0.128 seconds or more

MIL operation

Immediately

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

All

The monitor will run whenever the following DTCs are not present

None

Battery voltage

8 V or more

Ignition switch

ON

Starter

OFF

P0973: Range Check (Low Resistance)

Command to shift solenoid valve S1

ON

P0974: Range Check (High Resistance)

Command to shift solenoid valve S1

OFF

TYPICAL MALFUNCTION THRESHOLDS

P0973: Range Check (Low Resistance)

Shift solenoid valve S1 resistance

8 Ω or less

P0974: Range check (High Resistance)

Shift solenoid valve S1 resistance

100 kΩ or more

COMPONENT OPERATING RANGE

Shift solenoid valve S1 resistance

11 to 15 Ω at 20°C (68°F)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs (See page ).

HINT:

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

ECM gear shift command

1st

2nd

3rd

4th

5th

6th

Shift solenoid valve S1

OFF

ON

ON

ON

ON

ON

PROCEDURE

1.

INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE S1)

(a) Disconnect the D83 transmission wire connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

10 (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)

(a) Disconnect the D74 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D74-7 (S1) - Body ground

20°C (68°F)

11 to 15 Ω

Text in Illustration

*a

Front view of wire harness connector

(to ECM)

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.

INSPECT SHIFT SOLENOID VALVE S1

OK

REPAIR OR REPLACE TRANSMISSION WIRE

NG

REPLACE SHIFT SOLENOID VALVE S1

    Transmission Component Slipping (P0894,P2714)

    Shift Solenoid "B" Control Circuit Low (Shift Solenoid Valve S2) (P0976,P0977)

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