Reductant Temperature Sensor Circuit High
The P2045 code means the vehicle's onboard diagnostic system has detected: Reductant Temperature Sensor Circuit High. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $150 - $500 (parts and labor)
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Common Symptoms
- Check Engine Light illuminated
- DEF warning light on
- SCR system may overdose DEF
- Reduced engine power possible
- Speed limiter warning on dashboard
Probable Causes (Ranked by Likelihood)
- Short to voltage in DEF temperature sensor wiring Very High
- Defective DEF temperature sensor High
- Open ground in sensor circuit Moderate
- Corroded DEF tank connector Moderate
- PCM input driver issue Low
Frequently Asked Questions
What does P2045 mean?
P2045 means the DEF temperature sensor circuit is reading above the maximum expected voltage, typically from a wiring short to voltage or an open ground wire.
Can I drive with a P2045 code?
Short-distance driving is possible, but the SCR system will not function correctly and some vehicles may impose driving restrictions.
How much does it cost to fix P2045?
Expect $150 to $500 for sensor replacement or wiring repair, depending on vehicle configuration.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Read freeze frame data for P2045
-
Check DEF temperature sensor wiring for shorts to voltage
-
Verify sensor ground integrity at the connector
-
Compare sensor reading to independent temperature measurement
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2013-2020 Ram 2500 6.7L Cummins
- 2011-2019 Chevrolet Silverado 2500 6.6L Duramax
- 2009-2015 Volkswagen Jetta 2.0L TDI
- 2012-2018 BMW 328d 2.0L Diesel
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