Powertrain, generic (extended)

P2208 NOx Sensor Heater Sense Circuit (Bank 1 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Besides the control line, the NOx sensor heater has a sense or feedback path through which the controller checks how the heater actually responds (current, resistance or element temperature). P2208 marks a general fault in this sense circuit of the upstream sensor on bank 1. GM calls it NOx Sensor Heater Feedback Circuit (3.0L LZ0 diesel); Volvo and Mack class P2208 on the inlet sensor as a sensor failure that requires replacement. CARB demands heater performance monitoring within the supplier's limits. P2209 is the plausibility check of the same feedback, P2210/P2211 low or high values, P2212 dropouts; P2205-P2207 concern the control side. MIL on, driveability normal.

Likely causes

Internal fault in the NOx sensor or its control unit
Damaged wiring between sensor element and sensor control unit
Water ingress in the connector

Symptoms

  • Malfunction indicator lamp on
  • NOx sensor reports no valid value

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 wiring

Related codes

P2209P2210P2211P2212P2205P2221

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