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P2205 — Nox Sensor Heater Control Circuitopen Bank 1 Sensor 1

Manufacturer-specificPowertrain (engine & transmission)

The P2205 code indicates that the heater circuit for the first exhaust NOx sensor on Bank 1 is open, meaning the sensor's heating element is not receiving proper voltage or has a break in the circuit.

Symptoms

What causes it — most likely first

1. Failed NOx sensor heater element

The sensor's internal heating element can degrade or short open over time, interrupting the heater circuit.

2. Open or damaged heater circuit wiring

Wiring harness between the sensor and PCM may be broken, corroded, or have a loose connector.

3. Faulty heater relay or fuse

A blown fuse or malfunctioning relay in the heater power supply can cut power to the sensor heater.

4. PCM output circuit failure

The PCM's driver circuit that supplies heater voltage may fail, but this is less common than sensor or wiring issues.

How it's diagnosed

  1. Inspect the NOx sensor connector and wiring for corrosion, damage, or loose pins.
  2. Measure heater circuit resistance and voltage at the sensor connector with the key on.
  3. Check the associated fuse and relay for continuity and proper operation.
  4. Perform a resistance test on the sensor heater element to confirm it is within specifications.
  5. If wiring and sensor are sound, verify PCM heater driver output using a scan tool or multimeter.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Do I need to replace the entire PCM when I get a P2205 code?

No. The PCM is rarely the cause; most often the sensor heater, wiring, or a blown fuse is at fault, so those components should be checked first.

Can a bad NOx sensor cause this code?

The NOx sensor itself usually does not trigger P2205; the code specifically relates to the heater circuit, so a failed heater element or its wiring is the typical culprit.

Is the NOx sensor heater circuit related to fuel economy?

Not directly; the code affects emissions control, but an open heater circuit can cause the engine to run richer temporarily, which may slightly impact fuel consumption.

How long can I drive with a P2205 code?

Driving with the code is possible for a short period, but prolonged operation may lead to higher emissions, reduced performance, and potential failure of emissions testing.