P0743

Technical Definition:

Torque Converter Clutch Circuit Electrical

Trouble Code: P0743
Address: 0x0743
System: Powertrain
Subsystem: Transmission Controls
Technical Description:

The diagnostic trouble code is set when the Engine Management Computer (EMC) also known as the Powertrain Control Module (PCM) and also known as the Engine Control Module (ECM) detects a fault with the torque converter clutch (TCC) solenoid electrical circuit, which is contained inside the transmission.

Possible Causes:
  • Low or dirty transmission fluid
  • Wire/circuit issue shorted to power or ground
  • Failed torque converter clutch (TCC) solenoid
  • Failed TCC assembly in the torque converter
  • Failed PCM/ECM/EMC

Possible Symptoms:
  • Malfunction indicator illumination (check engine light or service engine soon light)
  • Stalling when coming to a stop after cruising speeds
  • Shudder on take off
  • Shudder when coming to a stop

Torque Converter Clutch Circuit Electrical

Possible Solutions:
  • On Board Diagnostic (OBD-II) scan tool – to pull the code; can be found at many parts stores, online, or many parts stores will pull the code for free
  • Multimeter that has a resistance (or OHM) reading
  • Self powered test light/probe (a Power Probe III works wonders here). If you don’t have a Power Probe, a simple set of fused jumper wires and a test light will suffice
  • Wire diagrams will be very helpful – you can get these in a Haynes manual or if your friendly with the dealer or your local mechanic, they may be able to run off a photocopy

OBD-II Trouble Code Type:

Diagnostic Step:

Tech Notes:

– Faulty torque converter clutch solenoid valve
– Torque converter clutch solenoid valve harness is open or shorted
– Torque converter clutch solenoid valve circuit poor electrical connection
– Low transmission fluid level
– Dirty transmission fluid

Specific Makes:

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