Transmission Fluid Temperature Sensor Circuit High
The P2743 code indicates that the transmission control module (TCM) has detected a voltage signal from the transmission fluid temperature (TFT) sensor that is higher than the expected range, typically above 4.9 volts. This can be caused by a faulty sensor, wiring issues (open circuit, short to voltage), or a problem with the TCM. The TFT sensor is a thermistor that changes resistance with temperature; a high voltage reading suggests the sensor is reading extremely cold or there is an electrical fault. This code can lead to improper transmission operation, as the TCM uses temperature data for shift scheduling and torque converter lockup.
01. Most Common Causes
- Faulty transmission fluid temperature sensor
- Open or shorted wiring in the TFT sensor circuit
- Poor electrical connection at the sensor or TCM
- Faulty transmission control module (TCM)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission may shift harshly or erratically
- Torque converter may not lock up properly
- Transmission may enter fail-safe or limp mode
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the TFT sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Using a multimeter, check the TFT sensor resistance at various temperatures (refer to manufacturer specs).
Step 4: Check for voltage at the sensor connector (should be 5V reference from TCM).
Step 5: If sensor and wiring are okay, test the TCM by checking output signals or swapping with a known good unit.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with this code, as the transmission may shift improperly, leading to potential internal damage. Limp mode may limit speed and gear selection.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and sensor replacement, but can be higher if wiring repairs or TCM replacement is needed.