Code Definition

P0740 — Torque Converter Clutch Circuit Malfuction

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0740

P0740 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0740 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0740 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The fault code P0740 is set when the Engine Control Module (ECM) or Transmission Control Module (TCM) detects an issue with the electrical circuit controlling the torque converter clutch (TCC). This code is triggered when the TCM cannot effectively control the clutch operation due to an electrical malfunction, typically outside the expected range of operation. This condition may lead to the torque converter clutch not engaging or disengaging properly.

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