P0740 on Mazda: How to Diagnose & Fix
Torque Converter Clutch Circuit Malfunction
1 Mazda model · 1 documented issue · $150-$1,800 repair
P0740 on Mazda by model: symptoms, diagnosis and fix
The 6-speed automatic transmission in the CX-3 develops a shudder or vibration during light-throttle acceleration at low to moderate speeds (20-45 mph). The torque converter lockup clutch is the typical culprit, with worn friction material causing slip-stick behavior. A transmission fluid change can temporarily resolve the issue, but severe cases require torque converter replacement.
Common Symptoms
- Vibration or shudder during light acceleration at 20-45 mph
- Feels like driving over rumble strips
- Shudder disappears under hard acceleration or deceleration
- Transmission temperature warning in extreme cases
How to Fix
Perform a complete transmission fluid drain and fill with Mazda ATF FW (not a flush). If shudder persists after fluid change, torque converter replacement is required. TCM reprogramming may also improve shift quality.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- BLAU/Ravenol CX-3 ATF-FZ drain-and-fill kit F2A1421-COEMBLAU F2A1421-C / Mazda ATF-FZ 0000-FZ-113E-01 specification
Measured drain-and-fill service for 2016-2021 CX-3 six-speed automatic Fitment/availability: Indexed direct page identifies five liters of ATF meeting Mazda 0000-FZ-113E-01 plus filter/service hardware, 2016-2021 CX-3 six-speed fitment, …
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Owner tips & cautions
- TipTry drain-and-fill (not flush) first - may resolve shudder for $150-200
- TipChange transmission fluid every 30,000 miles as preventive maintenance
- TipIf fluid change does not resolve it, torque converter replacement is the permanent fix - MazdaCX3Forum.com
Sources for this issue (1)
P0740 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0740 mean on a Mazda?
P0740 stands for "Torque Converter Clutch Circuit Malfunction." This code indicates a malfunction in the torque converter clutch (TCC) circuit of an automatic transmission. The torque converter clutch mechanically locks the engine to the transmission at cruising speed to improve fuel economy and reduce slippage, and it is engaged by a solenoid controlled by the transmission computer. The code sets when the computer detects an electrical problem with the clutch circuit or sees that the clutch is not engaging or holding as expected. Common signs include slipping, shuddering, poor fuel economy, or stalling when coming to a stop. On Mazda it is documented across 1 model: CX-3.
What are the most common causes of P0740?
The most common causes of P0740 are: Faulty torque converter clutch (TCC) solenoid, Low or contaminated transmission fluid, Wiring or connector fault in the TCC circuit, Worn or failing torque converter, Valve body wear or sticking valves, Internal transmission electrical short, Faulty transmission control module. The specific cause varies by vehicle.
How much does it cost to fix P0740 on a Mazda?
Published repair estimates on Mazda range from $150 to $1,800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0740 on a different make?
View P0740 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.