Transmission Codes

What does P0730 incorrect gear ratio mean?

The transmission computer compared input and output speeds and found the ratio did not match the commanded gear, which usually means slipping clutches, low or worn fluid, a solenoid problem or a speed sensor fault.

What does P0715 input or turbine speed sensor circuit mean?

Short answer: The transmission computer is not seeing a valid signal from the input or turbine speed sensor, caused by a failed sensor, wiring or connector problems, or debris on a magnetic sensor.

The input speed sensor tells the transmission computer how fast the input shaft or turbine is spinning. Without it, the computer cannot calculate slip or gear ratio, so shifts become harsh or the transmission goes into failsafe.

Look at live data while driving. An input speed reading of zero or one that drops out while output speed is normal points to the sensor circuit. Check the connector at the transmission, which can be exposed to fluid leaks and heat.

Many speed sensors are Hall effect or magnetic types. A scope shows a clean square wave from a Hall sensor or a sine wave from a magnetic sensor that increases with speed. Magnetic sensors collect metal debris, so cleaning may help but also indicates internal wear. Support the vehicle safely if you need to access the sensor from underneath.

What does P0741 torque converter clutch stuck off mean?

Short answer: The transmission computer commanded the torque converter clutch to apply but still saw too much slip between engine and turbine speed, which can be caused by a worn converter clutch, a solenoid or valve body problem, or fluid issues.

The torque converter clutch locks the engine to the transmission at cruise for better fuel economy. The computer compares engine speed to turbine speed; when commanded on, slip should drop to near zero. If it does not, P0741 sets.

Check fluid level and condition first. Then look at live data on a road test: commanded TCC state, TCC slip speed and the solenoid duty cycle. Slip that drops part way and then stalls suggests a weak clutch or pressure problem, while no change at all suggests an electrical or solenoid issue.

Test the solenoid circuit for resistance and the computer's command with a scope or meter. Check for bulletins, since some vehicles have known valve body wear or software updates. Converter replacement means removing the transmission, so confirm the diagnosis carefully and use proper transmission jack support during removal.

What does P0711 transmission fluid temperature sensor range or performance mean?

Short answer: The transmission fluid temperature reading did not change as expected or did not match other temperatures, which suggests a failing sensor, a wiring problem or an unusual cooling condition.

The transmission computer uses fluid temperature to adjust shift timing, line pressure and torque converter clutch operation. It expects the reading to rise after a cold start and to roughly follow engine temperature. If the reading stays flat, jumps or does not warm up, P0711 sets.

Compare transmission fluid temperature to engine coolant temperature after a cold soak. Both should start near ambient. Watch the fluid temperature as the vehicle warms; it should rise steadily. A fixed value or erratic jumps points to the sensor or wiring.

The sensor is often part of an internal harness in the transmission, so check the external connector first for fluid intrusion. Check the cooler and thermostatic valve if equipped, since a stuck valve can change warm-up behavior. Be careful when checking hot fluid, and allow the transmission to cool before removing the pan.

What does P0750 shift solenoid A mean?

Short answer: The transmission computer detected an electrical fault in shift solenoid A's circuit, such as an open, short, high resistance or failed solenoid.

Shift solenoids direct fluid to apply clutches or bands. The computer monitors each solenoid circuit and sets a code when current or voltage is outside normal limits. The transmission may default to a limp gear.

Begin with the wiring diagram to identify solenoid A for that transmission. Check the external connector for fluid contamination, corrosion and bent pins. Measure solenoid resistance through the connector and compare it with specifications, then check for shorts to ground or power.

If resistance is wrong, the problem may be the internal harness or the solenoid. Some transmissions use a solenoid pack or valve body with integrated electronics that require programming or adaptation after replacement. Use a scan tool to command the solenoid if supported. Allow the transmission to cool before draining fluid, and support the vehicle safely when working underneath.

What does P0720 output speed sensor circuit mean?

Short answer: The transmission computer is not getting a valid output shaft speed signal, often from a failed sensor, damaged wiring, a bad connector or a problem with the sensor's tone wheel.

The output speed sensor reports how fast the transmission output shaft is turning. Many vehicles also use it for the speedometer and cruise control, so symptoms can include a dead speedometer, erratic shifting and cruise not working.

Compare output speed to wheel speeds on a road test. If wheel speeds read normally but output speed drops to zero or jumps, focus on the sensor and its wiring. Check the connector and harness near the exhaust and driveshaft, where heat and movement cause damage.

Use a scope to view the sensor signal while spinning the wheels with the vehicle safely supported. A missing or distorted signal points to the sensor, wiring or tone wheel. Some vehicles take output speed from the ABS module, so check service information for the signal path before replacing parts. Never stand in line with rotating wheels while testing.

What does P0500 vehicle speed sensor A mean?

Short answer: P0500 means the engine or transmission module detected a problem with the vehicle speed sensor signal; check the sensor, wiring and related modules before replacing parts.

The vehicle speed signal is used by the engine, transmission, ABS and instrument cluster. P0500 sets when the module sees a missing, erratic or implausible speed signal.

Depending on the vehicle, the speed signal may come from a transmission output sensor, wheel speed sensors through the ABS module or another source. Symptoms can include an inoperative speedometer, harsh shifting and cruise control problems.

Check for other codes, look at live data for speed signals, and inspect sensor wiring and connectors. Use a scope to check the sensor signal if needed. Support the vehicle safely if testing with wheels off the ground, and keep clear of rotating parts.