Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0740/40: Lock-Up Control System
2004 Acura 3.5RLSECTION DTC P0740/40: Lock-Up Control System
NOTE:
Ensure any other DTCs are diagnosed first before proceeding with this test.
- Test 1st, 2nd, 3rd and 4th clutch pressure. See HYDRAULIC PRESSURE TESTS under PERFORMANCE TESTS. Repair as necessary. If clutch pressure readings are as specified, go to next step.
- Replace lock-up control solenoid valve "A" and "B" assembly. Reset PCM memory. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. After clearing DTC, drive vehicle at 55 MPH for longer than one minute in "D4" position. Recheck for DTC P0740/40. If DTC resets, replace transaxle and torque converter. If DTC does not reset, system is okay at this time.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.