Powertrain, generic (extended)

P2206 NOx Sensor Heater Control Circuit Low (Bank 1 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

A NOx sensor needs its ceramic element heated to several hundred degrees before it can measure. P2206 means the heater control circuit of the first (upstream) NOx sensor on bank 1 reads low, typically a short to ground or a driver output stuck low. CARB requires diesel OBD to detect heater circuit opens and shorts that conflict with the commanded state. GM's 3.0L Duramax (LZ0) lists it as NOx Sensor Heater Control Circuit Low; Volvo and Mack trucks treat P2206 on the inlet sensor as an internal sensor failure and replace the sensor. P2205 is the general heater circuit fault, P2207 the high side, P2208-P2211 the heater sense circuit. The SCR system loses NOx feedback.

Likely causes

Internal heater or control-unit fault in the NOx sensor
Heater wiring chafed to ground near the exhaust
Moisture or corrosion in the sensor connector

Symptoms

  • Malfunction indicator lamp on
  • SCR or emissions warning on the display
  • Usually no change in driveability

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€250–900
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

nox sensornox sensor heaternox sensor wiringecm

Related codes

P2205P2207P2208P2219P22A4

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.