Powertrain, generic (extended)

P2236 O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 2 Sensor 3)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2236 would be set if the heater of the third oxygen sensor on bank 2 leaked into its signal wire. Such a sensor sits furthest downstream and exists only on engines with two catalyst stages per bank. No manufacturer documents this code publicly, and Jaguar Land Rover's 2015 list for its V6 with sensors 3 on both banks does not use it either. The mechanism matches P2232/P2235: the heater is pulsed with battery voltage while the sensor signal stays below about 1 V, so any coupling shows up as a voltage step when the heater switches; GM uses more than 2 V within 0.04 s. CARB requires every monitored oxygen sensor circuit to be checked. P2233 is bank 1. Driving is unaffected; the lamp and a failed inspection are the consequences.

Likely causes

Internal leakage between heater and sensing element of sensor 3 on bank 2
Long underbody wiring to the rear sensor chafed or heat-damaged
Road salt corrosion in the sensor connector

Symptoms

  • Check engine light with normal driving behaviour
  • Readiness for catalyst or oxygen sensor monitor not set

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–280
Time0.4–1.5 h

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

Parts involved

oxygen sensor bank2 sensor3oxygen sensor heateroxygen sensor wiring

Related codes

P2233P2235P0062P0163P0164

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.