Reductant Temperature Sensor Circuit High
The P2045 code indicates that the reductant temperature sensor circuit, which monitors the temperature of the diesel exhaust fluid (DEF) in the selective catalytic reduction (SCR) system, is reporting a voltage higher than the expected range. This sensor is critical for proper DEF injection and emissions control. A high circuit condition typically points to a short to voltage, open ground, or a faulty sensor. If left unaddressed, it can lead to reduced engine performance, increased emissions, and potential damage to the SCR system.
01. Most Common Causes
- Faulty reductant temperature sensor
- Short to voltage in the sensor circuit
- Open or high resistance in the sensor ground circuit
- Corroded or damaged wiring/connectors
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Increased diesel exhaust fluid consumption
- Poor fuel economy
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve the code and verify P2045 is present.
Step 2: Visually inspect the reductant temperature sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Measure the sensor signal voltage at the ECU connector; compare to manufacturer specifications (typically 0.5-4.5V).
Step 4: Check for shorts to voltage or ground in the sensor circuit using a multimeter.
Step 5: If wiring is intact, replace the reductant temperature sensor and clear the code.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with this code, as it can cause the vehicle to enter limp mode and may damage the SCR system. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the sensor price and labor rates.