Reductant Tank Temperature Sensor Circuit High
The P205D code indicates that the reductant tank temperature sensor circuit is reading a voltage higher than the expected range. This sensor monitors the temperature of the diesel exhaust fluid (DEF) in the tank. A high voltage signal typically points to a short to power, open circuit, or a faulty sensor. This can affect the DEF system's ability to properly dose reductant, potentially leading to increased emissions and triggering the check engine light.
01. Most Common Causes
- Faulty reductant tank temperature sensor
- Short to power in the sensor circuit
- Open circuit or high resistance in wiring/connectors
- Corroded or damaged connector pins
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or limp mode
- Increased diesel exhaust fluid consumption
- Possible failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve freeze frame data and confirm the code.
Step 2: Visually inspect the reductant tank temperature sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Disconnect the sensor and measure resistance; compare to manufacturer specifications.
Step 4: Check for voltage at the sensor connector with key on; should be around 5V reference. If higher, suspect short to power.
Step 5: If wiring and sensor are okay, test the ECM for proper signal processing.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe to drive short distances, but the vehicle may enter limp mode to protect the emissions system. Prolonged driving could lead to increased emissions and potential damage to the DEF system.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on whether the sensor or wiring needs replacement.