Reductant Tank Temperature Sensor Circuit Range/Performance
The P205B code indicates that the reductant tank temperature sensor circuit is reporting a value outside the expected range or performance parameters. This sensor monitors the temperature of the diesel exhaust fluid (DEF) in the tank, which is critical for proper selective catalytic reduction (SCR) system operation. The powertrain control module (PCM) detects a signal that is either too high, too low, or not changing as expected, often due to sensor failure, wiring issues, or contamination.
1. Most Common Causes
- Faulty reductant tank temperature sensor
- Open or shorted wiring in the sensor circuit
- Poor electrical connection at the sensor or PCM
- Contaminated or incorrect DEF fluid affecting sensor readings
2. Symptoms You Will Notice
- Illuminated check engine light
- Reduced engine performance or limp mode
- Increased emissions or failed emissions test
- Possible DEF system warning messages on the dashboard
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes.
Step 2: Visually inspect the sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor resistance and compare to manufacturer specifications.
Step 4: Check the DEF fluid level and quality; replace if contaminated.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally not recommended to drive long distances with this code, as it can lead to reduced engine performance, increased emissions, and potential damage to the SCR system. However, short trips may be possible if the vehicle is not in limp mode.
How much does it cost to fix?▼
The cost to fix a P205B code typically ranges from $50 to $150 for parts and labor, depending on whether the sensor needs replacement or just a wiring repair.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.