P0756
U340E AUTOMATIC TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: P0756: Shift Solenoid "B" Performance (Shift Solenoid Valve S2)
DTC P0756 - Shift Solenoid "B" Performance (Shift Solenoid Valve S2)
DESCRIPTION
The ECM uses signals from the vehicle speed sensor and speed sensor NT to detect the actual gear position (1st, 2nd, 3rd or 4th).
Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect the mechanical problems of the shift solenoid valves, the valve body or automatic transaxle (clutch, brake or gear etc.).
HINT: Gear positions in the event of a solenoid valve mechanical problem:
MONITOR DESCRIPTION
This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of shift solenoid valve S2.
The ECM controls the gearshifts by turning the shift solenoid valves ON/OFF. When the gear position directed by the ECM and the actual gear position do not match, the ECM illuminates the MIL and stores the DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
The following conditions are common to all OFF malfunctions and ON malfunctions.
OFF malfunction (a):
OFF malfunction (b):
OFF malfunction (c):
ON malfunction (a):
ON malfunction (b):
ON malfunction (c):
TYPICAL MALFUNCTION THRESHOLDS
[OFF malfunction]
- All of the following conditions met: OFF malfunctions (a), (b) and (c)
2 detections are necessary per driving cycle.
1st detection: Temporary flag ON
2nd detection: Pending fault code ON
OFF malfunction (a):
OFF malfunction (b):
OFF malfunction (c):
[ON malfunction]
- All of the following conditions met: ON malfunctions (a), (b) and (c)
ON malfunction (a):
ON malfunction (b):
ON malfunction (c):
INSPECTION PROCEDURE
1. ACTIVE TEST
HINT: Performing the Active Test using the Techstream allows components, such as the relay, VSV, and actuator, to be operated without removing any parts. Performing the Active Test as the first step of troubleshooting is one method of shortening labor time.
It is possible to display the Data List during the Active Test.
(a) Warm up the engine.
(b) Turn the ignition switch off.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON.
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine and ECT / Active Test.
(g) In accordance with the display on the Techstream, perform the Active Test.
HINT: While driving, the shift position can be forcibly changed using the Techstream.
Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem Fail-Safe Chart.
HINT:
- This test can be conducted when the vehicle speed is 30 mph (50 km/h) or less.
- The 3rd to 4th up-shifting must be performed with the accelerator pedal released.
- The 4th to 3rd down-shifting 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 more than once in succession.
- The shift position commanded by the ECM is shown in the Data List/Shift Status display on the Techstream.
- Shift solenoid valve S2 is turned on/off normally when the shift lever is in the D position:
PROCEDURE
1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0756)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs using the Techstream.
Result
HINT: If any other DTCs besides P0756 are output, perform troubleshooting for those DTCs first.
B -- GO TO DTC CHART
A -- Continue to next step.
2. INSPECT SHIFT SOLENOID VALVE S2
(a) Remove shift solenoid valve S2.
(b) Measure the resistance.
Standard resistance:
(c) Connect the positive (+) lead to the terminal of the solenoid connector and the negative (-) lead to the solenoid body to check the solenoid valve operation.
OK:
The solenoid makes operating sounds.
NG -- REPLACE SHIFT SOLENOID VALVE S2
OK -- Continue to next step.
3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
OK:
There are no foreign objects on any valves and they operate smoothly.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK -- REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY