What causes fault code P0545?

• Most likely: Defective EGT sensor (internal short) • Likely: Damaged wiring harness due to high heat exposure (short to ground) • Possible: Corrosion or oxidation in the sensor connector • Rare: Faulty ECM software or an internal failure in the control module

Powertrain (Engine & Gearbox)Standard EOBD

P0545 - Exhaust Gas Temperature Sensor Circuit Low - Bank 1 Sensor 1

Q: What are the symptoms of fault code P0545?

• Check engine light (MIL) is illuminated • Vehicle may enter 'Limp Mode' (reduced engine power) • Failure to complete DPF regeneration cycles • Increased fuel consumption • Emissions test failure

Q: How do you fix fault code P0545?

STEP 1: Visual inspection of the wiring loom near the exhaust system. Look for melted insulation or chafing causing a short to ground. Clean the electrical connector. STEP 2: Multimeter testing. Disconnect the sensor and measure resistance. A value near 0 Ohm usually indicates an internal short. Also, verify the reference voltage (typically 5V) from the ECM at the harness connector. STEP 3: Check for continuity between the signal wire and the chassis to confirm a wiring short to ground. STEP 4: Component replacement. If the wiring is sound but the sensor is faulty, replace the EGT sensor. Clear the DTC and perform a test drive to ensure the DPF system can initiate regeneration.

Last updated:1 February 2026

Related:EGT Sensor (Exhaust Gas Temperature Sensor), Engine Control Module (ECM), Wiring Harness, Diesel Particulate Filter (DPF)

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0500

Vehicle Speed Sensor (VSS) 'A' Range/Performance

P0501

Vehicle Speed Sensor 'A' Range/Performance

P0502

Vehicle Speed Sensor 'A' Circuit Low Input

P0503

Vehicle Speed Sensor (VSS) Intermittent/Erratic/High

Technical Description

P0545 is a generic diagnostic trouble code (DTC) that indicates the Engine Control Module (ECM) detected a low voltage signal from the Exhaust Gas Temperature (EGT) sensor 1 for Bank 1. This sensor is a thermal resistor that changes ohm values based on temperature. A 'low' circuit condition typically signifies a short to ground in the wiring or an internal failure of the sensor element itself. The ECM uses this data to manage engine fueling, timing, and exhaust aftertreatment systems such as DPF regeneration.

Possible Causes

Defective EGT sensor (internal short)

Damaged wiring harness due to high heat exposure (short to ground)

Corrosion or oxidation in the sensor connector

Faulty ECM software or an internal failure in the control module

Symptoms

Check engine light (MIL) is illuminated

Vehicle may enter 'Limp Mode' (reduced engine power)

Failure to complete DPF regeneration cycles

Increased fuel consumption

Emissions test failure

Do you also have
other fault codes?

See how P0545 connects with your other fault codes. Our advanced analysis tool identifies causal relationships and root causes directly.

Analyze multiple codes

P0545 - Exhaust Gas Temperature Sensor Circuit Low - Bank 1 Sensor 1

Related Fault Codes

Technical Description

Possible Causes

Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have
other fault codes?

P0545 - Exhaust Gas Temperature Sensor Circuit Low - Bank 1 Sensor 1

Related Fault Codes

Technical Description

Possible Causes

Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have other fault codes?

Do you also have
other fault codes?