P0708
UniversalTransmission Range Sensor Circuit High Input
Medium SeverityThe P0708 code indicates that the Powertrain Control Module (PCM) has detected a higher-than-expected voltage signal from the Transmission Range Sensor circuit. This typically means the PCM cannot accurately determine the engaged gear, which can lead to issues with starting, shifting, or displaying the correct gear.
⚠️ Before You Begin (Safety First)
Always disconnect the battery before working on electrical components. Be aware that the vehicle may not shift correctly or could start in an unexpected gear. Use jack stands when working under the vehicle to ensure stability.
Common Symptoms
- Check Engine Light illuminated
- Vehicle may not start or starts only in Neutral/Park
- Incorrect gear display on the dashboard
- Harsh or erratic shifting
- Vehicle stuck in one gear (limp mode)
- Backup lights not working
Common Causes
- Faulty Transmission Range Sensor
- Corroded or damaged wiring/connectors in the sensor circuit
- Short to voltage in the Transmission Range Sensor circuit
- Faulty Powertrain Control Module (PCM) (less common)
- Transmission fluid contamination or low fluid level affecting sensor operation
Frequently reported on: General/Universal
Diagnostic Steps
- Inspect the Transmission Range Sensor and its wiring harness for visible damage, corrosion, or loose connections.
- Check the transmission fluid level and condition; low or dirty fluid can sometimes affect sensor operation.
- Using a multimeter, test the voltage at the Transmission Range Sensor connector according to your vehicle's service manual specifications to confirm a high input.
- If the sensor tests faulty or shows signs of internal shorting, replace the Transmission Range Sensor.
- Clear the P0708 code and test drive the vehicle to ensure the repair is successful.
👨🔧 When to Call a Professional
If diagnosing the Transmission Range Sensor circuit involves complex electrical testing or requires specialized tools, it is best to consult a professional mechanic to avoid further damage to the transmission control system.
Commonly Asked Questions
Can I drive with a P0708 code?
It is not recommended to drive with a P0708 code, as it can lead to unpredictable shifting, prevent the vehicle from starting, or cause it to start in the wrong gear, posing a safety risk.
Where is the Transmission Range Sensor located?
The Transmission Range Sensor is typically located on the side of the transmission, usually near the shift linkage, but its exact position can vary by vehicle make and model.
Is replacing the Transmission Range Sensor difficult?
Replacing the sensor is generally considered a medium difficulty task for DIYers. It often involves accessing the transmission, which may require lifting the vehicle and sometimes draining some transmission fluid.
Does a P0708 code always mean the sensor is bad?
Not always. While a faulty sensor is common, the code can also be triggered by issues with the wiring harness, connectors, or even a problem with the vehicle's Powertrain Control Module (though this is less frequent).