Nissan Altima 2007-2012 Service Manual: P0841 pressure sensor function

Description

Using the engine load (throttle position), the primary pulley revolution speed, and the secondary pulley revolution speed as input signal, TCM changes the operating pressure of the primary pulley and the secondary pulley and changes the groove width of the pulley to control the gear ratio.

DTC Logic

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE


DTC CONFIRMATION PROCEDURE

CAUTION: Always drive vehicle at a safe speed.

NOTE: If “DTC CONFIRMATION PROCEDURE” has been previously performed, always turn ignition switch OFF.

Then wait at least 10 seconds before performing the next test.

1.CHECK DTC DETECTION

1. Turn ignition switch ON.


1. Turn ignition switch ON.

2. Select “DATA MONITOR”.

3. Start engine and maintain the following conditions for at least 12 consecutive seconds.

Is “P0841 PRESS SEN/FNCTN” detected?


Is “P0841 PRESS SEN/FNCTN” detected? YES >> Go to TM-344, "Diagnosis Procedure".

NO >> Check intermittent incident. Refer to GI-42, "Intermittent Incident".

Diagnosis Procedure

1.CHECK LINE PRESSURE

Perform line pressure test. Refer to TM-423, "Inspection and Judgment".

Is the inspection result normal? YES >> GO TO 2.

NO >> Repair or replace damaged parts. Refer to TM-423, "Inspection and Judgment".

2.CHECK TRANSMISSION FLUID PRESSURE SENSOR A (SECONDARY PRESSURE SENSOR) SYSTEM

Check transmission fluid pressure sensor A (secondary pressure sensor) system. Refer to TM-341, "Description".

Is the inspection result normal? YES >> GO TO 3.

NO >> Repair or replace damaged parts.

3.CHECK PRESSURE CONTROL SOLENOID VALVE A (LINE PRESSURE SOLENOID VALVE)

1. Turn ignition switch OFF.

2. Disconnect CVT unit connector.

3. Check pressure control solenoid valve A (line pressure solenoid valve). Refer to TM-345, "Component Inspection [Pressure Control Solenoid Valve A (Line Pressure Solenoid Valve)]".

Is the inspection result normal? YES >> GO TO 4.

NO >> Replace transaxle assembly. Refer to TM-447, "Exploded View".

4.CHECK PRESSURE CONTROL SOLENOID VALVE B (SECONDARY PRESSURE SOLENOID VALVE)

Check pressure control solenoid valve B (secondary pressure solenoid valve). Refer to TM-345, "Component Inspection [Pressure Control Solenoid Valve B (Secondary Pressure Solenoid Valve)]".

Is the inspection result normal? YES >> GO TO 5.

NO >> Replace transaxle assembly. Refer to TM-447, "Exploded View".

5.CHECK STEP MOTOR SYSTEM

Check step motor system. Refer to TM-361, "Description".

Is the inspection result normal? YES >> GO TO 6.

NO >> Repair or replace damaged parts.

6.DETECT MALFUNCTIONING ITEMS

Check TCM connector pin terminals for damage or loose connection with harness connector.

Is the inspection result normal? YES >> Replace TCM. Refer to TM-430, "Exploded View".

NO >> Repair or replace damaged parts.

Component Inspection [Pressure Control Solenoid Valve A (Line Pressure Solenoid Valve)]

1.CHECK PRESSURE CONTROL SOLENOID VALVE A (LINE PRESSURE SOLENOID VALVE)

Check resistance between CVT unit terminal 2 and ground.


Is the inspection result normal?


Is the inspection result normal? YES >> INSPECTION END

NO >> Replace transaxle assembly. Refer to TM-447, "Exploded View".

Component Inspection [Pressure Control Solenoid Valve B (Secondary Pressure Solenoid Valve)]

1.CHECK PRESSURE CONTROL SOLENOID VALVE B (SECONDARY PRESSURE SOLENOID VALVE)

Check resistance between CVT unit terminal 3 and ground.


Is the inspection result normal?


Is the inspection result normal? YES >> INSPECTION END

NO >> Replace transaxle assembly. Refer to TM-447, "Exploded View".

    P0840 transmission fluid pressure sensor A (sec pressure sensor)
    Description The transmission fluid pressure sensor A (secondary pressure sensor) detects secondary pressure of CVT and sends TCM the signal. DTC Logic DTC DETECTION LOGIC DTC CONFIRMATION PR ...

    P0868 secondary pressure down
    Description The pressure control solenoid valve B (secondary pressure solenoid valve) regulates the secondary pressure to suit the driving condition in response to a signal sent from the TCM. DTC ...

    Other materials:

    B260C steering lock unit
    Description The electronic steering column lock performs the check by itself according to the steering status. DTC Logic DTC DETECTION LOGIC DTC CONFIRMATION PROCEDURE 1.PERFORM DTC CONFIRMATION PROCEDURE 1. Turn ignition switch ON. 2. Turn ignition switch OFF. 3. Press door switch. ...

    Battery
    How to Handle Battery CAUTION: • If it becomes necessary to start the engine with a booster battery and jumper cables, use a 12-volt booster battery. • After connecting battery cables, ensure that they are tightly clamped to battery terminals for good contact. • Never ad ...

    Air conditioning cut control
    System Diagram System Description INPUT/OUTPUT SIGNAL CHART *1: This signal is sent to the ECM via the CAN communication line. *2: ECM determines the start signal status by the signals of engine speed and battery voltage. SYSTEM DESCRIPTION This system improves engine operation when t ...