DTC P0742 [FN4A-EL]

id0502a1808000

DTC P0742

Torque converter clutch (TCC) stuck on

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 70 km/h {43 mph} or less
- Torque converter clutch (TCC) not operating
- Difference between engine speed and turbine speed 50 rpm or less
- DTC P0734 not output
• Throttle conditions
- Throttle opening angle (TP PID) is 10% or more and 5 s or more have passed.
- Throttle opening angle (TP PID) is within 3-10% 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?
Yes
Go to the next step.
No
If the ATF color is milky or reddish brown, replace ATF, then go to Step 4.
3

INSPECT ATF LEVEL

• Start the engine.
• Warm up the ATX.
• Is the ATF level within the specification?
Yes
Go to the next step.
No
Add ATF to the specified level, then go to Step 6.
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: 990-1,160 kPa {10.1-11.8 kgf/cm2, 144-168 psi}

• Are the line pressures within the specifications?
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 automatic transaxle, then go to Step 6.
(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 ATX Workshop Manual FN4A-EL.)
Yes
Replace the automatic transaxle, then go to the next step.
(See ATX Workshop Manual FN4A-EL.)
No
Repair or replace the shift valve and return spring, then go to the next step.
(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: 70 km/h {43 mph} or less.
• Throttle conditions
- Throttle opening angle (TP PID) 10% or more and 5 s or more have passed.
- Throttle opening angle (TP PID) within 3-10% 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.
No
Go to the next step.
7

VERIFY AFTER REPAIR PROCEDURE

• Perform the "After Repair Procedure".
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
DTC troubleshooting completed.