Emissions

P2207 — NOx Sensor Heater Control Circuit Low (Bank 2 Sensor 1)

Severity: medium Drive with care, to a shop

What P2207 means

A NOx sensor in the exhaust needs a heater to reach operating temperature quickly and measure nitrogen oxides accurately. The engine control unit, or a module built into the sensor, drives the heater and monitors its circuit voltage. With P2207, the bank 2 sensor heater circuit reads lower than expected. This usually points to an open circuit, a short to ground, or a failed heater element. Exact code definitions can vary by manufacturer, so confirm the bank and sensor with a scan tool.

Symptoms

  • Check engine light or SCR/AdBlue warning
  • NOx fault appearing after a cold start
  • Reduced power or a warning about upcoming power limiting
  • Abnormal AdBlue consumption or dosing
  • Failed emissions test

Possible causes

  1. Failed heater inside the bank 2 NOx sensor
  2. Open circuit or short to ground in the heater wiring
  3. Corroded or damaged sensor connector
  4. Wiring damaged by exhaust heat
  5. Faulty NOx sensor control module
  6. Rarely, an engine control unit fault

How to diagnose

  1. Read all codes and freeze frame data and confirm the fault is on bank 2.
  2. Check for other NOx, SCR, power supply or CAN network codes.
  3. Inspect the sensor, connector and harness for melting, chafing, corrosion and moisture.
  4. Measure supply voltage and ground at the sensor connector with the ignition on.
  5. Test the heater control circuit for opens and shorts to ground using the factory wiring diagram.
  6. With a scan tool, watch heater status and NOx readings on a warm engine.
  7. If the wiring is good, replace the NOx sensor and clear the codes.
  8. Road test and confirm the code does not return.

Common fixes

  • Replace the bank 2 NOx sensor
  • Repair or replace the damaged wiring harness
  • Clean or replace a corroded connector
  • Re-secure the wiring and shield it from exhaust heat
  • Update control unit software if the manufacturer offers it

Questions and answers

Can I drive with code P2207?

For a short time, yes, but get it fixed soon. The SCR system may limit engine power, and emissions can exceed legal limits.

What most often causes P2207?

Usually a NOx sensor with a failed heater, or damaged wiring near the hot exhaust. Check the harness and connector first, then replace the sensor if they test good.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.