How is fault code P0740 fixed?

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read all the codes, not just this one. P0741 alongside P0740 points more at performance and slip than a pure wiring fault, and a wall of gearbox codes usually means a sick box rather than one solenoid 2. Check the fluid level and condition properly. Pull the dipstick where there is one, or check at the fill plug. You want it red and clean, not brown and smelling burnt. Dark, burnt fluid changes the whole conversation 3. Inspect the gearbox connector and harness for corrosion, melted insulation or a loose pin. Wiggle-test it with the scanner watching live data 4. Test the TCC solenoid circuit for continuity and resistance with a multimeter and compare against the spec for that box 5. Take it for a road test above 45 mph watching live data, and look at the difference between converter RPM and input shaft speed. If it commands lock-up and the revs don't drop, you've confirmed it's not just a lazy sensor reading 6. If the wiring, fluid and solenoid all check out, the converter or internals

Torque Converter Clutch Circuit Malfunction

Jump to the fix

Severity

High

Can I keep driving?

Avoid extended driving; visit a service soon.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read all the codes, not just this one. P0741 alongside P0740 points more at performance and slip than a pure wiring fault, and a wall of gearbox codes usually means a sick box rather than one solenoid 2. Check the fluid level and condition properly.

PPowertrain
0Generic code
7Transmission
40Sequence number

What does it mean?

DTC P0745: When the transmission solenoid malfunctions, in most cases the problem is not the electrical part of the solenoid; the problem is generally foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. The line pressure solenoid valve regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the TCM (Transmission Control Module) or PCM (Powertrain Control Module).

NOTE: Whenever diagnosing a 700 series DTC (Diagnostic Trouble Code) with a transmission, transfer case or other driveline components, check for a DTC under chassis and body systems, not just under “P” or powertrain/engine or emission control type codes. Module communications DTCs are “U” codes. These are most often found when looking for DTCs under chassis or body systems.

Chassis related codes are labeled “C” and body system related codes are labeled “B” codes and these can cause drivetrain issues if they affect a sensor that is also used by the heating and air conditioning system. DTC P0745 sets when the PCM or TCM has detected an abnormality in the electronic pressure control solenoid circuit. Computer controlled automatic transmissions use variable amounts of hydraulic pressure to provide shifting and TCC (torque converter clutch) operation.

Symptoms

Likely causes

How to fix it

Codes From the Same System

All Fault Codes

Related Similar Codes

This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.