Severity High
P205C

Reductant Tank Temperature Sensor Circuit Low

📅 Last reviewed: July 2026
What does the P205C code mean?

The P205C code indicates that the reductant tank temperature sensor circuit is reading a voltage lower than the expected range. This sensor monitors the temperature of the diesel exhaust fluid (DEF) in the tank. A low voltage reading typically points to a short to ground, a faulty sensor, or wiring issues. This can affect the DEF system's ability to properly dose fluid for emissions control, potentially leading to increased NOx emissions and triggering the check engine light.

High
Severity
$50-$150
Typical Cost
High
Frequency

1. Most Common Causes

2. Symptoms You Will Notice

3. Step-by-Step Diagnosis

1

Step 1: Use a scan tool to confirm the code and check for related codes.

2

Step 2: Visually inspect the sensor and wiring for damage, corrosion, or loose connections.

3

Step 3: Measure the sensor resistance and compare to manufacturer specifications; replace if out of range.

4

Step 4: Check for shorts to ground in the circuit using a multimeter.

4. 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 can cause 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.

5. Commonly Affected Makes

This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.

6. Related Codes

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