P0748

DTC P0748: Line Pressure Linear Solenoid Valve System

SOLENOID VALVE SYSTEM CIRCUIT

Refer to P0743.

DESCRIPTIONS OF MONITOR METHODS

When the battery voltage is 2 V or more

- Open or short circuit is detected for 5 seconds.

- The control current of solenoid valve is abnormally large or small.

MONITOR EXECUTION

- Continuous

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)

- Not applicable
Sensor (The sensor below is determined to be normal)

- Not applicable

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Check Conditions [Circuit continuity ground]

- Voltage of battery: 2 volts or more.
Judgment Criteria [Circuit continuity ground]

- Line pressure linear solenoid valve actual current: more than 1.7 A (1 second)
Check Conditions [Circuit continuity open]

- Voltage of battery: 2 volts or more.

- Line pressure linear solenoid valve activation command: more than 625 mA
Judgment Criteria [Circuit continuity open]

- Line pressure linear solenoid valve actual current: less than 190 mA. (5 seconds)

OBD-II DRIVE CYCLE PATTERN

Start the engine, and maintain the status for approximately 10 seconds. Then, turn the ignition switch from OFF to ON, restart the engine, and then maintain the status for approximately 10 seconds.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)

- Malfunction of the line pressure linear solenoid valve system circuit

- Damaged harness or connector

- Malfunction of the TCM

- Malfunction of the line pressure linear solenoid valve (valve body assembly)

DIAGNOSIS

STEP 1. Check the TCM terminal voltage.

[C-37 TCM connector (vehicle side, connected)]

Measure the voltage between the terminal No. 40 and body ground.

- While driving: 300 Hz

- Other than above: 0 V

Q. Is the check result normal?

YES Go to Step 5.
NO Go to Step 2.
STEP 2. Check between the TCM connector and A/T control solenoid valve assembly connector.

Check for continuity between C-37 TCM connector and B-111 A/T control solenoid valve assembly connector.

NOTE:
Prior to the wiring harness inspection, check the intermediate connectors A-12 and repair that if necessary.

- Between C-37 terminal No. 40 and B-111 terminal No. 9: Continuity exists.

When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness.

Q. Is the check result normal?

YES Go to Step 3.
NO Repair or replace the failure section.
STEP 3. Check the line pressure linear solenoid.

Refer to Testing and Inspection.

Q. Is the check result normal?

YES Go to Step 6.
NO Go to Step 4.
STEP 4. Check between the A/T control solenoid valve assembly connector and the line pressure linear solenoid valve connector.

Check for continuity between the A/T control solenoid valve assembly connector terminals and the line pressure linear solenoid valve connector terminals.

- Between C-111 terminal No. 9 and line pressure linear solenoid valve: Continuity exists.

Q. Is the check result satisfactory?

YES Replace the valve body assembly.
NO Repair or replace the failure section.
STEP 5. Check the TCM and A/T control solenoid valve assembly connector pin terminals and the connection status.

Q. Is the check result normal?

YES Go to Step 7.
NO Repair or replace the failure section.
STEP 6. Check the TCM and A/T control solenoid valve assembly connector pin terminals and the connection status.

Q. Is the check result normal?

YES Replace the TCM.
NO Repair or replace the failure section.
STEP 7. Erase the DTC code, and drive the vehicle for a while.

Check that the normal code is displayed.

Q. Is the check result normal?

YES The procedure is complete.
NO Return to START.