Powertrain, generic (extended)

P2246 O2 Sensor Reference Voltage Circuit High (Bank 1 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2246 means the reference voltage line of the bank 1 front wide-band sensor reads too high, typically from a short to battery or heater voltage or a short inside the sensor. No manufacturer publishes a threshold for P2246. GM's 2018 Duramax table 18OBDG04 names it, together with P2245, P2252 and P2253, as a fault that makes the front sensor signal unusable, but gives no setting criteria. Ford logs any wide-band lead that is shorted to supply voltage as P0132 and keeps P2243 for the open line, so Ford vehicles do not use this code. Bosch limits the Nernst cell to a 250 microamp load, which is why an external voltage on this wire can damage the sensor or the interface. CARB requires circuit faults of fuel-control sensors to be detected. P2245 is the low fault, P2250 bank 2.

Likely causes

Reference voltage wire shorted to heater supply or battery voltage
Internal short between heater and Nernst cell in the sensor
Fault in the sensor interface of the ECM

Symptoms

  • Check engine light
  • Higher fuel consumption
  • Repeat failure of a new sensor if the wiring short remains

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–450
Time0.5–2 h

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

Parts involved

oxygen sensor bank1 sensor1oxygen sensor wiringecm

Related codes

P2243P2245P2250P2239P0132

References: gsi.ext.gm.com, newtonnet.co.uk, bosch-motorsport.com, law.cornell.edu.