The P0712 code in your 2021 Honda CR-V indicates that the transmission fluid temperature sensor circuit is reading lower voltage than expected. This code specifically tells us the circuit is shorted to ground or has another issue that pulls the voltage down, causing the TCM to see an abnormally cold temperature reading.
What Low Circuit Voltage Means
The TFT sensor works by varying resistance based on temperature. When the circuit shows low voltage, the TCM interprets this as a very cold temperature reading—potentially colder than physically possible. A short to ground pulls voltage down, making the sensor appear to read extreme cold even when the transmission is warm.
Common Causes in the CR-V
A short to ground in the TFT sensor wiring is the primary cause. This can occur from chafed insulation, pinched wires, or water intrusion. The sensor itself may have failed in a shorted condition. Corroded connectors can create ground paths through moisture. In some cases, internal transmission electrical issues affect the sensor circuit.
How This Affects Transmission Operation
When the TCM believes the transmission is extremely cold, it adjusts operation accordingly—this might include extended high-pressure operation, delayed torque converter lockup, or other "cold" behaviors that aren't appropriate for actual warm conditions. This leads to poor fuel economy, harsh shifts, or excessive transmission wear.
Diagnostic Steps
Using Honda HDS, monitor the TFT reading. If it shows extremely cold temperatures when the engine is warm, the sensor circuit has a grounding issue. Disconnect the sensor and check if voltage at the connector is now normal—if so, the sensor is internally shorted. Check wiring for damage, especially where it routes near exhaust components or through grommets.