Gate Select Position Circuit Low
The P0906 code indicates that the transmission control module (TCM) has detected a low voltage condition in the gate select position sensor circuit. This sensor is part of the shift-by-wire system used in some automatic transmissions to determine the selected gear (Park, Reverse, Neutral, Drive). A low voltage signal suggests a short to ground, open circuit, or faulty sensor, which can prevent the transmission from shifting properly or cause incorrect gear selection.
01. Most Common Causes
- Faulty gate select position sensor
- Short to ground in the sensor circuit wiring
- Open circuit or poor connection in the sensor harness
- Failed transmission control module (TCM)
02. Symptoms You Will Notice
- Transmission stuck in one gear or fails to shift
- Check Engine Light illuminated
- Incorrect gear indication on the dashboard
- Vehicle may not start or shift out of Park
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 gate select position sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's voltage and resistance per manufacturer specifications using a multimeter.
Step 4: If the sensor is faulty, replace it; if wiring issues are found, repair as needed.
Step 5: Clear the code and test drive to verify repair.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. The transmission may not shift correctly, leading to loss of power or unexpected gear changes, which can cause an accident.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor. The sensor itself costs $50-$150, and labor adds $100-$250 depending on the vehicle.