Toyota 4Runner manuals

Toyota 4Runner: Pressure Control Solenoid "B" Electrical (Shift Solenoid Valve SL2) (P0778)

Toyota 4Runner Service Manual / Drivetrain / A750e Automatic Transmission / Transaxle / Automatic Transmission System / Pressure Control Solenoid "B" Electrical (Shift Solenoid Valve SL2) (P0778)

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 are 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 (See page ).


DTC Code

DTC Detection Condition

Trouble Area

P0778

The ECM checks for an open or short in the shift solenoid valve SL2 circuit while driving and shifting gears (1-trip detection logic).

Output signal duty ratio equals 100%.

HINT:

SL2 output signal duty is less than 100% under normal conditions.

  • Open or short in shift solenoid valve SL2 circuit
  • Shift solenoid valve SL2
  • ECM

MONITOR DESCRIPTION

This DTC indicates an open or short in the shift solenoid valve SL2 circuit. The ECM commands gear shifts by turning the shift solenoid valves ON/OFF. 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. Then the ECM performs the fail-safe function and turns the other normal shift solenoid valves ON/OFF. In case of an open or short circuit, the ECM stops sending current to the circuit.

While driving and shifting gears, if the ECM detects an open or short in the shift solenoid valve SL2 circuit, the ECM determines there is a malfunction (See page ).


MONITOR STRATEGY

Related DTCs

P0778: Shift solenoid valve SL2/Range check

Required sensors/Components

Shift solenoid valve SL2

Frequency of operation

Continuous

Duration

1 sec.

MIL operation

Immediate

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

All

The monitor will run whenever the following DTCs are not stored

None

Battery voltage

8 V or higher

Ignition switch

ON

Starter

OFF

Condition (A)

Solenoid current cut status

Not cut

Battery voltage

11 V or higher

Target duty cycle

19% or more

Condition (B)

Target duty cycle

100%

TYPICAL MALFUNCTION THRESHOLDS

Solenoid status from solenoid driver MIC

Failure

COMPONENT OPERATING RANGE

Output signal duty

Less than 100%

WIRING DIAGRAM


CAUTION / NOTICE / HINT

NOTICE:

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


HINT:

The shift solenoid valve SL2 turns ON/OFF normally when the shift lever is in D.

ECM gear shift command

1st

2nd

3rd

4th

5th

Shift solenoid valve SL2

ON

ON

ON

ON

OFF

PROCEDURE

1.

INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL2)

(a) Disconnect the B32 transmission wire connector.


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

Standard Resistance:

Tester Connection

Condition

Specified Condition

11 (SL2+) - 3 (SL2-)

20°C (68°F)

5.0 to 5.6 Ω

11 (SL2+) - Body ground

Always

10 kΩ or higher

3 (SL2-) - Body ground

Always

10 kΩ or higher

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 B37 and B38 ECM connectors.


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

Standard Resistance:

Tester Connection

Condition

Specified Condition

B37-31 (SL2+) - B38-34 (SL2-)

20°C (68°F)

5.0 to 5.6 Ω

B37-31 (SL2+) - Body ground

Always

10 kΩ or higher

B38-34 (SL2-) - Body ground

Always

10 kΩ or higher

Text in Illustration

*a

Rear view of wire harness connector

(to ECM)


OK

REPLACE ECM


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.

INSPECT SHIFT SOLENOID VALVE SL2



OK

REPAIR OR REPLACE TRANSMISSION WIRE


NG

REPLACE SHIFT SOLENOID VALVE SL2

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