A750F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0973,P0974; Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1); 2006 MY LX470 [05/2005

Last Modified: 4-30-2014	6.6 C	Doc ID: RM000000W8600IX
Model Year: 2006	Model: LX470	Prod Date Range: [05/2005 - ]
Title: A750F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0973,P0974; Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1); 2006 MY LX470 [05/2005 - ]

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 the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated safely .

DTC No.	DTC Detection Condition	Trouble Area
P0973	ECM detects short in 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 open in 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 and illuminates the MIL and stores the DTC. When the shift solenoid valve S1 is ON, if resistance is 8 Ω or less, the ECM determines that there is a short in the shift solenoid valve S1 circuit.

When the shift solenoid valve S1 is OFF, if resistance is 100 kΩ or more, the ECM determines that there is an open in the shift solenoid valve S1 circuit .

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 sec. or more
MIL operation	Immediately
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

P0973: Range check (Low resistance)

The monitor will run whenever this DTC is not present.	None
Shift solenoid valve S1	ON

P0974: Range check (High resistance)

The monitor will run whenever this DTC is not present.	None
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

INSPECTION PROCEDURE

HINT:

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

ECM gear shift command	1st	2nd	3rd	4th	5th
Shift solenoid valve S1	ON	ON	OFF	OFF	OFF

PROCEDURE

1.	INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE S1)

(a) Disconnect the E1 wire connector.

(b) Measure the resistance of the transmission wire.

Standard resistance:

Tester Connection	Condition	Specified Condition
8 - Body ground	20°C (68°F)	11 to 15 Ω

GO TO STEP 3

2.	CHECK WIRE HARNESS (TRANSMISSION WIRE - ECM)

(a) Disconnect the E7 ECM connector.

(b) Measure the resistance of the wire harness side connector.

Standard resistance:

Tester Connection	Condition	Specified Condition
E7-11 (S1) - Body ground	20°C (68°F)	11 to 15 Ω

REPAIR OR REPLACE HARNESS AND CONNECTOR

REPLACE ECM

3.	INSPECT SHIFT SOLENOID VALVE S1

(a) Remove the shift solenoid valve S1.

(b) Measure the resistance of the solenoid valve.

Standard resistance:

5.0 to 5.6 Ωat 20°C (68°F)

(c) Connect the battery's positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body.

OK:

Solenoid makes operating noise.

REPLACE SHIFT SOLENOID VALVE S1

REPAIR OR REPLACE TRANSMISSION WIRE