P0162

P0162 means the ECM is seeing an out-of-range electrical condition on the bank 2 sensor 3 O2 sensor circuit — typically open-circuit, shorted, or stuck-at-bias-voltage. Bank 2 sensor 3 is the third O2 sensor in the bank 2 exhaust stream, which on most V6/V8/V10 platforms is a second post-cat sensor (sometimes called the tailpipe sensor) used for in-use catalyst monitor verification on OBD-II compliant platforms with dual cats per bank. Cheapest-first ladder: confirm the connector is fully seated and the locking tab is intact (heat soak from the exhaust crumbles locking tabs first); back-probe the signal wire with the engine at warm closed-loop idle and look for the narrow-band sensor to sit relatively flat between 0.4-0.7V (a post-cat sensor on a healthy cat should NOT oscillate the full 0.1-0.9V range like an upstream sensor), or for a wideband, lambda steady around 1.0 (0.7-1.3 acceptable swing under load); check the heater current draw at cold start, which should pull 0.5-2A on most narrow-band heaters; ohm the heater element (typical 6-15 ohms cold) and confirm the heater B+ feed is hitting 12V+ with key on. If the signal voltage is pegged at 0V or stuck at the bias voltage (typically 0.45V on Ford/GM) regardless of fuel trim changes, the sensor or its harness is open-circuit. Expensive-misdiagnosis caveat: a chafed harness against the exhaust pipe or transfer case crossmember mimics a dead sensor identically — never condemn a $180 sensor before ohmming the harness end-to-end.

Vehicle-specific patterns: 2003-2010 Dodge Ram 1500/2500 with the 5.7L Hemi runs dual post-cat sensors per bank on emissions-strict-state VINs and throws P0162 frequently from harness chafe where the bank 2 (passenger) sensor 3 wire routes over the transfer case crossmember — the chafe-through is faster than the sensor wears out. 2004-2014 Ford F-150 with the 5.4L 3V and 6.2L Boss V8 throws P0162 on California-emissions trucks from connector heat-soak melt where the bank 2 sensor 3 connector sits too close to the rear exhaust collector; Ford rerouted the pigtail on later builds. 2007-2014 Toyota Tundra/Sequoia with the 5.7L 3UR-FE commonly throws P0162 from the post-cat sensor pigtail rubbing the frame rail crossmember. 2008-2013 BMW E70 X5 4.8i / 5.0i (N62/N63) throws P0162 from the well-known coolant intrusion into the post-cat sensor connector after a valley pan leak. Estimated repair: $80 to $450.