P0544 — Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 1 — 6.7 Cummins (EGR + DPF, pre-SCR)

P0544 on 6.7 Cummins (EGR+DPF, pre-SCR) indicates an electrical fault in the Bank 1 Sensor 1 exhaust gas temperature sensor circuit. The ECM uses EGT inputs to…

Updated October 15, 2026

What it means

Generic definition: The ECM has detected a fault in the bank 1 sensor 1 exhaust gas temperature sensor circuit. On the 6.7L Cummins the EGT sensors control regeneration.¹

Most likely causes

1. EGT sensor element or internal wiring failure — Open or shorted thermocouple/RTD inside the sensor produces an out-of-range signal the ECM flags as a circuit fault.¹
2. Connector or harness damage at the exhaust/manifold area — Heat, vibration and soot degrade the sensor connector and wiring near the exhaust, causing intermittent opens or shorts.¹
3. Chafed or melted wiring to the ECM — Exhaust heat and routing can melt insulation, leading to shorts to ground or power on the EGT signal/return wires.¹
4. ECM input fault for the EGT circuit — Internal ECM pull-up/pull-down or reference voltage issue can set a circuit fault even with a good sensor and harness.¹

How to diagnose

1. Verify code and freeze frame; confirm P0544 is present and note engine/aftertreatment conditions at set.
2. Inspect EGT sensor and connector near the exhaust; look for heat damage, corrosion, oil/coolant contamination, and secure seating.
3. Perform a visual and wiggle test of the EGT harness from sensor to main loom; check for chafing, melted insulation, and proper routing away from hot surfaces.
4. Check EGT sensor reference/return voltages and bias per service information with key on engine off; compare to expected values and inspect for shorts to ground or battery.
5. Monitor live EGT data while gently manipulating the harness; erratic or implausible readings indicate wiring/connector faults.
6. If circuit tests normal, evaluate ECM inputs and consider substitution testing with a known-good EGT sensor before condemning the ECM.
7. After repair, clear codes and confirm DPF regeneration control uses plausible EGT readings; no further codes should set during a drive cycle.
8. If regeneration remains inhibited, inspect related aftertreatment inputs such as DPF differential pressure sensor hoses and sensor plausibility, as bad temperature data can upset regeneration strategy.

Parts and tools you may need

• Digital multimeter
• Scan tool with live data and bi-directional controls
• Inspection light and mirror
• Dielectric grease
• Replacement EGT sensor and pigtail if damaged

Tools you’ll need

• digital multimeter — Checks EGT sensor reference/return voltages and bias per service info with key on engine off, and detects shorts to ground or battery in the EGT circuit.
• OBD-II scan tool — Verifies P0544 presence, reviews freeze frame conditions, and monitors live EGT data while manipulating the harness to spot erratic readings.
• inspection mirror — Allows visual inspection of the EGT sensor and connector near the hot exhaust/manifold for heat damage, corrosion, and secure seating.
• wiring probe kit — Supports wiggle testing of the EGT harness from sensor to main loom to find chafing, melted insulation, and intermittent opens.

Rough cost and difficulty

Typical US independent-shop figures; labor runs about $120–$180 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

If wiring faults are extensive, the sensor is seized in the exhaust, or ECM input testing is required, have a qualified diesel technician perform diagnosis and repair. Do not service high-pressure fuel injection systems. If the vehicle shows loss of power, excessive smoke, or repeated regeneration inhibition, seek professional diagnosis promptly.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources