P2743 indicates the Transmission Fluid Temperature (TFT) Sensor B circuit is reading a higher-than-expected voltage signal to the transmission control module. This typically means the sensor is detecting temperatures that are outside normal operating range, either due to an actual overtemperature condition or a sensor/wiring failure causing an artificially high reading.
The sensor itself is faulty, internally shorted, or has degraded, causing it to report incorrect high-temperature readings to the TCM.
Low fluid level or burnt/contaminated fluid can cause abnormal temperature readings and trigger this code.
Damaged, shorted, corroded, or loose wiring between sensor B and the TCM can cause high-voltage signals.
An actual overheating condition from heavy towing, insufficient cooling, or stuck thermostat can trigger legitimate high-temp readings.
Restricted fluid flow through the transmission cooler can cause localized overheating read by sensor B.
The transmission or engine control module could have an internal circuitry fault, but this is the least likely cause and should be investigated only after ruling out all sensor and wiring issues.
Almost never. The transmission control module is very rarely the culprit for P2743. In the vast majority of cases, the issue is the sensor itself, the wiring, or an actual overtemperature condition from low fluid or cooling problems. Technicians who immediately suggest a new TCM are usually incorrect and this leads to unnecessary expensive repairs.
Prolonged driving is not recommended. If the code is triggered by a real overtemperature condition, continued driving can cause severe transmission damage. If the reading is false due to sensor failure, the transmission may be at risk because the TCM cannot properly monitor fluid temperatures. Drive to a repair facility only if the vehicle is not showing severe symptoms.
OEM or high-quality aftermarket sensors that meet manufacturer specifications are recommended. Using incorrect sensors can cause persistent codes or inaccurate temperature readings that lead to transmission damage.