Gate Select Position Circuit Low Voltage
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 in automatic transmissions, determining the selected gear (Park, Reverse, Neutral, Drive). Low voltage may be caused by a faulty sensor, damaged wiring, poor electrical connections, or a malfunctioning TCM. This can lead to incorrect gear selection or transmission malfunction.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission stuck in one gear or fails to shift
- Incorrect gear indication on dashboard
- Vehicle may not start or shift out of Park
2. Most Common Causes
- Faulty gate select position sensor
- Damaged or corroded wiring/connectors in the sensor circuit
- Short to ground in the sensor signal circuit
- Malfunctioning transmission control module (TCM)
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0906 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 ground signals using a multimeter; compare with manufacturer specifications.
Step 4: If sensor and wiring are okay, test the TCM for proper output signals; replace TCM if faulty.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not recommended. The transmission may not shift correctly or could get stuck in gear, leading to unsafe driving conditions.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the sensor, wiring, or TCM needs replacement and labor rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.