Powertrain, generic (extended)

P2250 O2 Sensor Reference Voltage Circuit High (Bank 2 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2250 signals that the reference voltage line of the upstream wide-band sensor on bank 2 is too high, as happens with a short to the heater feed or battery voltage, or a breakdown inside the ceramic. No manufacturer documents P2250 publicly, and no bulletin in the NHTSA index names it. Ford sends any wide-band wire shorted to supply voltage to P0152 and uses P2247 only for the open line, so Ford engines never store it. Because Bosch allows the Nernst cell only a 250 microamp load, an outside voltage on this lead can ruin a replacement sensor unless the wiring is repaired first. CARB requires fuel-control sensors to be monitored for circuit faults, with distinct codes where practical. P2246 is the bank 1 counterpart, P2249 the low fault, P2247 the open circuit.

Likely causes

Reference voltage wire of the bank 2 sensor shorted to heater supply or battery voltage
Internal short between heater and Nernst cell
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 bank2 sensor1oxygen sensor wiringecm

Related codes

P2246P2247P2249P2242P0152

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