OBD-II Code · Transmission
P0740
Torque Converter Clutch Circuit Malfunction
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$200–$1,500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Torque converter clutch solenoid fault.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
- Shudder at highway speeds
- Poor fuel economy
Likely causes
- Failed TCC solenoidMost common
- Low trans fluid
- Internal converter wear
Read the full diagnostic procedureP0740 means the TCM has detected an electrical fault in the Torque Converter Clutch (TCC) solenoid circuit — open, shorted, or out-of-range resistanc…
P0740 means the TCM has detected an electrical fault in the Torque Converter Clutch (TCC) solenoid circuit — open, shorted, or out-of-range resistance on the solenoid that controls converter lockup. This is a 'circuit' code, not a 'performance' code (that's P0741) — meaning the TCM can't even verify the solenoid is electrically there. Start with the fluid check and condition, then go straight to the external harness at the transmission case connector: P0740 is one of the highest-rate connector-corrosion false-positives in the diagnostic catalog. Unplug the case connector, inspect for green corrosion or pin pushback, dielectric-grease everything, clear the code, and road-test. If the code returns, the next step is a resistance check across the TCC solenoid pins at the case connector — most TCC solenoids spec between 10-30 ohms (verify with FSM). Out-of-spec resistance is a solenoid swap; in-spec resistance points to wiring upstream toward the TCM. The solenoid itself is almost always replaced as part of a solenoid pack on modern trans, not individually.
Vehicle-specific patterns2002-2007 Honda Accord/Odyssey 5AT throws P0740 from a known TCC solenoid failure — Honda part number 28250-P7W-003, $40-80 part, accessible external…
- 2002-2007Honda Accord/Odyssey 5AT throws P0740 from a known TCC solenoid failure — Honda part number 28250-P7W-003, $40-80 part, accessible externally without dropping the pan, 30-minute job.
- 2004-2010Ford Mustang/F-150 with the 4R70W/4R75E throws P0740 from harness corrosion at the case pass-through connector far more often than from an actual solenoid failure — 80% of these codes resolve with connector cleanup and dielectric grease per Ford TSB 06-14-4.
- 2003-2009Toyota 4Runner/Tundra with the A750E/A750F throws P0740 from a degraded TCC solenoid that's accessible after pan drop — $80 solenoid plus pan gasket.
- 2005-2010GM Silverado/Tahoe with the 4L60E throws P0740 from internal harness chafing at the case pass-through OR a failed TCC PWM solenoid in the valve body — pan drop required either way.
Estimated repair$150 (connector cleanup) to $600 (solenoid + pan service).
Look up another code
P0740 — frequently asked
What does a P0740 code mean?
Torque converter clutch solenoid fault.
What causes a P0740 code?
Common causes: Failed TCC solenoid; Low trans fluid; Internal converter wear.
What are the symptoms of a P0740 code?
Typical symptoms: Check engine light; Shudder at highway speeds; Poor fuel economy.
Is it safe to drive with a P0740 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $200-$1,500.
How do I diagnose a P0740 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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