P0740

TECHNICAL DESCRIPTION
- When a malfunction of the torque converter clutch or its related system is detected, the transaxle control CPU inside the powertrain control module (PCM) outputs a malfunction signal to the engine control CPU in the PCM.

DTC SET CONDITIONS
Check Conditions, Judgment Criteria
- Failed signal of the torque converter clutch or its related system is input to the engine control CPU from the transaxle control CPU.

TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Torque converter clutch or its related system failed.
- Open or shorted torque converter clutch or its related system circuit, or loose connector.
- PCM failed.

DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch is to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.




STEP 1. Using scan tool MB991502, read the A/T diagnostic trouble code (DTC).
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Read the A/T-DTC.

If the A/T-DTC is output, refer to Automatic Transaxle Diagnosis - Trouble Code Descriptions Chart. Testing and Inspection

If the A/T-DTC is not output, it is suspected that an MFI-DTC has not been erased after repairing the A/T component. If DTC P0705 is output again after the MFI-DTC has been erased, replace the PCM.
Then check that DTC P0740 does not reset.