Dtc P0756 Shift Solenoid B Performance (Shift Solenoid Valve S2)

Lexus IS250 IS220d GSE20 ALE20 - A960E AUTOMATIC TRANSMISSION

SYSTEM DESCRIPTION

MONITOR DESCRIPTION

INSPECTION PROCEDURE

CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0756)

INSPECT SHIFT SOLENOID VALVE S2

INSPECT TRANSMISSION VALVE BODY ASSEMBLY

DTC P0756 Shift Solenoid "B" Performance (Shift Solenoid Valve S2)

SYSTEM DESCRIPTION

The ECM uses signals from the output shaft speed sensor and input speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).


Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

DTC No.DTC Detection ConditionTrouble Area
P0756
S2 stuck ON malfunction*1:
Shifting to 3rd and 5th gears is impossible.
The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic)
When the ECM directs the gearshift to switch to 5th gear, the actual gear is shifted to 6th.
When the ECM directs the gearshift to switch to 6th gear, the actual gear is shifted to 6th.
Shift solenoid valve S2 remains open
Valve body is blocked
Automatic transmission (clutch, brake or gear, etc.)
↑
S2 stuck OFF malfunction*2:
The vehicle starts in 3rd gear and shifting to 6th gear is impossible.
The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic)
When the ECM directs the gearshift to switch to 1st gear, the actual gear is shifted to 3rd.
When the ECM directs the gearshift to switch to 6th gear, the actual gear is shifted to 5th.
Shift solenoid valve S2 remains closed
Valve body is blocked
Automatic transmission (clutch, brake or gear, etc.)
  • HINT:
Gear positions in the event of a solenoid valve mechanical problem:
ECM command gearshift1st2nd3rd4th5th6th
*1: Actual gear position under S2 stuck ON malfunction↑↑2nd↑6th↑
*2: Actual gear position under S2 stuck OFF malfunction3rd3rd3rd↑5th5th

MONITOR DESCRIPTION

This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of the shift solenoid valve S2.


The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position commanded by the ECM and the actual gear position are not the same, the ECM illuminates the MIL and stores the DTC.


INSPECTION PROCEDURE

ACTIVE TEST
  • HINT:
  • Performing the intelligent tester Active Test allows relay, Vacuum Switching Valve (VSV), actuator and other items to be operated without removing any parts. Performing the Active Test early in troubleshooting is one way to shorten labor time.
  • The Data List can be displayed during the Active Test.

Warm up the engine.

Turn the engine switch off.

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG) position.

Turn on the tester.

Select the item "Enter / Powertrain / ECT / Active Test".

Follow the instructions on the tester and read the Active Test.

  • HINT:
  • While driving, the shift position can be forcibly changed with the intelligent tester.
  • Comparing the shift position commanded by the ACTIVE TEST with the actual shift position enables you to confirm the problem .
ItemTest DetailsDiagnostic Note
Control Shift Position [Test Details]
Operate the shift solenoid valve and set each shift position by yourself.
[Vehicle Condition]
IDL: ON (4th, 5th and 6th)
Less than 50 km/h (31 mph)
[Others]
Press "→" button: Shift up
Press "←" button: Shift down
 Possible to check the operation of the shift solenoid valves.
  • HINT:
This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.
The 4th to 5th and 5th to 6th up-shiftings must be performed with the accelerator pedal released.
The 6th to 5th and 5th to 4th down-shiftings must be performed with the accelerator pedal released.
Do not operate the accelerator pedal for at least 2 seconds after shifting and do not shift successively.
The shift position commanded by the ECM is shown in the DATA LIST (Shift Status) display on the intelligent tester.
The shift solenoid valve S1 is turned on/off normally when the shift lever is in the D position:
ECM command gearshift1st2nd3rd4th5th6th
Shift solenoid valve S1OFFONONONONON
1.CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0756)

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG) position.

Turn on the tester

Select the item "Powertrain / ECT / DTC / Current or Pending".

Read the DTCs using the intelligent tester.

  • Result:
  • Display (DTC output)Proceed to
    Only "P0756" is outputA
    "P0756" and other DTCsB
  • HINT:
  • If any other codes besides "P0756" are output, perform troubleshooting for those DTCs first.
B
GO TO DTC CHART
A
2.INSPECT SHIFT SOLENOID VALVE S2
Dtc P0756 Shift Solenoid B Performance (Shift Solenoid Valve S2). A960E AUTOMATIC TRANSMISSION. Lexus IS250 IS220d GSE20 ALE20

Remove the shift solenoid valve S2.

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

  • Standard resistance:
  • Tester ConnectionSpecified Condition
    20°C (68°F)
    Solenoid Connector (S2) - Solenoid Body (S2)11 to 15 Ω

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

  • OK:
  • The solenoid makes an operating sound.
NG
REPLACE SHIFT SOLENOID VALVE S2
OK
3.INSPECT TRANSMISSION VALVE BODY ASSEMBLY
  • OK:
  • There are no foreign objects on each valve.
NG
REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK
REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY