P0708 - Transmission Range Sensor Circuit High Input
The P0708 code indicates that the Powertrain Control Module (PCM) has detected a high voltage signal from the transmission range sensor (TRS), also known as the neutral safety switch or manual lever position sensor. This sensor tells the PCM which gear position (Park, Reverse, Neutral, Drive) the driver has selected. A high input means the voltage is above the expected range, often due to a short to power, a faulty sensor, or wiring issues. This can cause incorrect gear selection, starting problems, or transmission performance issues.
01. Most Common Causes
- Faulty transmission range sensor
- Short to voltage in the sensor circuit
- Damaged wiring or connector
- Corrosion or poor electrical connection
- Faulty PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission stuck in limp mode or one gear
- Engine starts in any gear or won't start
- Incorrect gear display on dashboard
- Harsh or erratic shifting
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related codes.
Step 2: Visually inspect the transmission range sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage and resistance with a multimeter according to manufacturer specifications.
Step 4: Check for a short to power by disconnecting the sensor and measuring voltage at the harness connector.
Step 5: If all tests pass, suspect a faulty PCM and perform further diagnostics.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with P0708 as it can cause unpredictable transmission behavior, including sudden gear engagement or inability to shift, which may lead to accidents or further transmission damage.
How much does it cost to fix?▼
The cost to fix P0708 typically ranges from $50 to $150 for parts and labor, depending on whether the sensor needs replacement or just a wiring repair. Diagnostic fees may add $50-$100.