FixItFor.Us
P codepowertrainMedium severity

P0549Exhaust Gas Temperature Sensor Circuit High (Bank 2, Sensor 1)

The exhaust gas temperature sensor 1 circuit on Bank 2 is reading abnormally high voltage, usually meaning an open circuit or disconnected sensor.

Definition

The PCM monitors the Bank 2, Sensor 1 exhaust gas temperature sensor and sets P0549 when the signal voltage rises above the plausible range, which for an NTC thermistor reads as an impossibly cold exhaust. This is the classic signature of an open sensor element, broken wire, or unplugged connector. The MIL illuminates, and because the PCM can no longer verify Bank 2 exhaust temperatures it may limit boost, enrich fueling, or block DPF regeneration on diesels, leading to reduced power and progressive soot loading.

Common causes

  • Failed EGT sensor with an open element from repeated heat cycling
  • Broken or open signal wire in the Bank 2 harness
  • Unplugged, melted, or corroded sensor connector
  • Open sensor ground/return circuit
  • Terminal backed out of the connector cavity
  • Faulty PCM input circuit (rare)

Common misdiagnoses

  • DPF or catalytic converter replaced for regeneration or temperature faults
  • Turbocharger replaced for limp-mode power loss
  • Bank 1 sensor replaced due to bank confusion
  • Exhaust manifold suspected for temperature anomalies

Troubleshooting steps

  1. 1.Confirm the failure signature in live data

    With the engine fully warm, a Bank 2 Sensor 1 EGT stuck at -40 C or minimum scale indicates an open circuit.

  2. 2.Verify the correct bank and sensor location

    Bank 2 is the bank opposite cylinder 1; consult the service manual so you test the correct sensor before replacing parts.

  3. 3.Inspect the connector and wiring

    Look for a disconnected or heat-damaged connector, backed-out pins, and wiring broken at flex points near the engine.

  4. 4.Measure sensor resistance

    An OL (open) reading across the sensor terminals at any temperature confirms a failed sensor.

  5. 5.Check harness continuity to the PCM

    With both ends disconnected, verify each circuit shows less than about 1 ohm end to end and no short to power.

  6. 6.Clear the code and road test

    Drive through a full warm-up and highway load cycle, confirming the Bank 2 EGT PID tracks Bank 1 closely and the code stays clear.

Related codes