P2045 Fault Code

Reductant Temperature Sensor Circuit High

• What does that mean?
• Symptoms
• Causes
• Solutions

The P2045 fault code indicates an issue with the reductant temperature sensor circuit being too high. This sensor is critical in monitoring the temperature of the diesel exhaust fluid (DEF) within the reductant system, which is essential for the proper operation of diesel vehicles equipped with selective catalytic reduction (SCR) systems. An elevated temperature reading can lead to improper DEF injection and potential exhaust system damage if not addressed.

What are the symptoms of the P2045 code?

Symptoms of a P2045 code may manifest as:

• Illuminated check engine light on the dashboard
• Poor engine performance or reduced power
• Increased emissions due to malfunctioning SCR system
• Possible default or limp mode activation in the vehicle’s operation to protect the engine and exhaust system.

What causes the P2045 code?

Common causes of a P2045 fault code can include:

• A malfunctioning reductant temperature sensor
• Electrical issues such as a short circuit or open circuit in the sensor wiring
• Corrosion or damaged connectors in the sensor circuit
• Defective engine control module (ECM) interpreting faulty data from the sensor
• Excessive ambient temperatures affecting sensor function.

How to fix P2045?

To resolve the P2045 fault code, consider the following steps:

• Inspect the reductant temperature sensor and its wiring for damage or corrosion.
• Test the sensor with a multimeter to ensure it's operating within specification.
• Check the vehicle’s ECM for any software updates or error codes.
• Replace the sensor if it is found to be defective.
• Clear the fault codes and perform a test drive to confirm the issue has been resolved.