Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 1)
The P0545 code means the vehicle's onboard diagnostic system has detected: Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 1). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light on
- DPF regeneration may not initiate
- Reduced engine power
- Turbo boost limited
Probable Causes (Ranked by Likelihood)
- Short to ground in EGT sensor wiring Very High
- Failed EGT sensor with internal short High
- Water or condensation in EGT sensor connector Moderate
- Damaged wiring harness near exhaust manifold Moderate
Step-by-Step Diagnostic Procedure
-
Read EGT sensor 1 temperature; an abnormally low reading when engine is warm confirms the circuit issue
-
Disconnect the EGT sensor and check for short to ground on the signal wire
-
Inspect sensor connector for water intrusion or corrosion
-
Measure sensor resistance; a very low reading indicates an internal short
Frequently Asked Questions
What does circuit low mean for an EGT sensor?
Circuit low means the ECM is reading a voltage that indicates a temperature far below what is expected. Since EGT sensors use varying resistance with temperature, a short to ground creates a falsely low reading.
Can P0545 prevent DPF regeneration?
Yes. The DPF regeneration process requires accurate exhaust temperature data. If the ECM cannot confirm exhaust temperatures are high enough, it will not initiate regeneration, potentially leading to a clogged DPF.
Why do EGT sensor wires get damaged?
EGT sensor wiring runs near the exhaust system where temperatures can exceed 1000F. Over time, heat degrades wire insulation, causing shorts between wires or shorts to ground against the exhaust or engine block.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0545 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
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