DTC P0742 [FN4A-EL]

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DTC P0742 [FN4A-EL]

B3E050219090W19

DTC P0742 | Torque converter clutch (TCC) stuck on
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DETECTION CONDITION

• All of the following conditions are satisfied under each of the following throttle conditions.

  - ATF temperature 20 °C {68 °F} or more
  - Driving in 4GR at D or M range
  - Engine running
  - Turbine speed within 225-4,987 rpm
  - Vehicle speed below 70 km/h {43 mph}
  - Torque converter clutch (TCC) no operating
  - Difference between engine speed and turbine speed below 50 rpm
  - DTC P0734 not output

• Throttle conditions

  - Throttle opening angle (TP PID) is above 10% and 5 s or more have passed.
  - Throttle opening angle (TP PID) is within 3.13-10% and 3 s or more have passed.
  - Throttle opening angle is at closed throttle position and 5 s or more have passed.

Diagnostic support note:
• This is a continuous monitor (CCM).
• The MIL does not illuminate if PCM detects the above malfunction conditions during first the drive cycle.
• A PENDING CODE is not available.
• FREEZE FRAME DATA is not available.
• The AT warning light illuminates.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• ATF level low
• Deteriorated ATF
• Shift solenoids A, B, C, D, E, and pressure control solenoid stuck
• Line pressure low
2-4 brake band slipping
3-4 clutch slipping
• Control valve stuck
• PCM malfunction

Diagnostic procedure

STEP | INSPECTION | ACTION
--- | --- | ---
1 | VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related Service Bulletins and/or on-line repair information availability. • Is any related repair information available? | Yes | Perform repair or diagnosis according to the available repair information. • If the vehicle is not repaired, go to the next step.
No | Go to the next step.

2

INSPECT ATF CONDITION

• Turn the ignition switch to the LOCK position.
• Inspect the ATF condition.

  - Clear red: Normal
  - Milky: Water mixed in fluid
  - Reddish brown: Deteriorated ATF

• Is it normal?
(See Automatic Transaxle Fluid (ATF) Condition Inspection.)

Yes

Go to the next step.

No | If the ATF color is milky or reddish brown, replace ATF, then go to Step 4. (See AUTOMATIC TRANSAXLE FLUID (ATF) REPLACEMENT.)
3 | INSPECT ATF LEVEL • Start the engine. • Warm up the ATX. • Is the ATF level within the specification? (See Automatic Transaxle Fluid (ATF) Level Inspection.) | Yes | Go to the next step.
No | Add ATF to the specified level, then go to Step 6. (See Automatic Transaxle Fluid (ATF) Level Inspection.)

4

INSPECT LINE PRESSURE

• Start the engine.
• Measure the line pressure.

Specification

Idle: 330-470 kPa {3.4-4.7 kgf/cm2, 48-68 psi}

Stall:

1,090-1,250 kPa {11.2-12.7 kgf/cm2, 159-181 psi} (Z6)

1,160-1,320 kPa {11.8-13.5 kgf/cm2, 168-191 psi} (LF)

• Are the line pressures within the specifications?
(See Line Pressure Test.)

Yes

Go to the next step.

No | • All ranges: Replace the oil pump or control valve body, then go to Step 6. • Any ranges: Replace the ATX, then go to Step 6. (See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION [Z6].) (See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION [LF].) (See ATX Workshop Manual FN4A-EL.)

5

INSPECT OPERATION OF EACH VALVE AND EACH SPRING

• Turn the ignition switch to the LOCK position.
• Remove the control valve body.
• Disassemble the control valve body.
• Is each valve operation normal and is the return spring normal?
(See CONTROL VALVE BODY REMOVAL.)
(See CONTROL VALVE BODY INSTALLATION.)
(See ATX Workshop Manual FN4A-EL.)

Yes

Replace the ATX, then go to the next step.
(See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION [Z6].)
(See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION [LF].)
(See ATX Workshop Manual FN4A-EL.)

No | Repair or replace the shift valve and return spring, then go to the next step. (See CONTROL VALVE BODY REMOVAL.) (See CONTROL VALVE BODY INSTALLATION.) (See ATX Workshop Manual FN4A-EL.)

6

VERIFY TROUBLESHOOTING OF DTC P0742 COMPLETED

• Make sure to reconnect all the disconnected connectors.
• Clear the DTC from the memory using the WDS or equivalent.
• Start the engine.
• Warm up engine and ATX.
• Drive the vehicle under the following conditions:

  - ATF temperature: 20 °C {68 °F} or more
  - Drive in the D range, 4GR (TCC not in operation)
  - Vehicle speed: below 70 km/h {43 mph}.

• Throttle conditions

  - Throttle opening angle (TP PID) above 10% and 5 s or more have passed.
  - Throttle opening angle (TP PID) within 3.13-10% and 3 s or more have passed.
  - Throttle opening angle at closed throttle position and 5 s or more have passed.

• Are any DTCs present?

Yes

Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [ZJ, Z6].)
(See PCM REMOVAL/INSTALLATION [LF].)

No | Go to the next step.
7 | VERIFY AFTER REPAIR PROCEDURE • Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE [FN4A-EL].) • Are any DTCs present? | Yes | Go to the applicable DTC inspection.
No | DTC troubleshooting completed.