Transmission Range Sensor Not Learned
The P280A code indicates that the transmission range sensor (TRS) has not completed its learning procedure. This sensor tells the transmission control module (TCM) which gear position (Park, Reverse, Neutral, Drive) is selected. When the circuit is not learned, the TCM cannot accurately determine the gear selector position, leading to potential shifting issues or failure to start. This often occurs after battery disconnection, transmission replacement, or sensor replacement, requiring a relearn procedure.
1. Most Common Causes
- Battery or power loss causing loss of learned values
- Transmission range sensor replacement without relearn
- Transmission control module (TCM) replacement or reset
- Faulty transmission range sensor
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission may not shift properly or stuck in one gear
- Vehicle may not start or start in wrong gear
- Erratic or no gear position display on dashboard
3. Step-by-Step Diagnosis
Step 1: Connect a scan tool and verify P280A code. Check for other related codes.
Step 2: Perform transmission range sensor relearn procedure using scan tool (follow manufacturer specific steps).
Step 3: If relearn fails, inspect wiring and connector for damage or corrosion at the sensor.
Step 4: Test sensor resistance and voltage per service manual; replace if out of spec.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The transmission may not shift correctly, and the vehicle may not start or could start in gear, posing a safety risk.
How much does it cost to fix?▼
Typically $50-$150 for a relearn procedure at a shop. If sensor replacement is needed, costs can be higher ($200-$400).
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.