Possible causes

– Faulty Transmission Fluid Temperature Sensor
– Transmission Fluid Temperature Sensor harness is open or shorted
– Transmission Fluid Temperature Sensor circuit poor electrical connection

When is the code detected?

Transmission Control Module (TCM) detects excessively low voltage from the fluid temperature sensor.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Possible shifting problems

P0712 BUICK Description

The Automatic Transmission Fluid Temperature (TFT) sensor is a resistor, or thermistor, which changes value based on temperature. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases, and as the temperature decreases, the resistance increases. The Powertrain Control Module (PCM) supplies a 5-volt reference signal to the sensor and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the PCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases.

BUICK Technical Service Bulletins for P0712 code