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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What Are the Symptoms of P2045?
- Check Engine Light illuminated
- DEF warning light on
- SCR system may overdose DEF
- Reduced engine power possible
- Speed limiter warning on dashboard
What Causes P2045? (Most Likely First)
- 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
Can I Still Drive with P2045?
Short distances only. P2045 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
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
How Do You Diagnose P2045?
-
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
Which Vehicles Commonly Get P2045?
- 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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