Powertrain, generic (extended)

P2235 O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 2 Sensor 2)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2235 concerns the post-catalyst oxygen sensor on bank 2, found on V engines with a catalyst per bank. The ECM sets it when switching off the heater makes the sensor voltage spike. GM runs the check only once the sensor is past its dew-point phase and the modelled exhaust has been above 250 °C for 90 s (and below 800 °C); the failure threshold, as for P2232, is a jump above 2 V within 0.04 s in more than 4 of 6 switch-offs. It appears in the 2005 2.8/3.6 V6 tables, the 2008 3.6 LLT tables and the 2024 set 24OBDG07, each with the MIL after two trips. Because the fault is tied to one sensor position, swapping banks is a quick plausibility check before parts are ordered. P2232 is bank 1, P2234 the front sensor of bank 2.

Likely causes

Internal leakage between heater and sensing element of the bank 2 rear sensor
Sensor wires damaged by heat or chafing near the bank 2 catalyst
Water ingress in the rear sensor connector

Symptoms

  • Check engine light after two drives
  • Bank 2 catalyst monitor not completed

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 sensor2oxygen sensor heateroxygen sensor wiring

Related codes

P2232P2234P2236P0056P0157P0158

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.