P2240

P2240 is the high-current side of the wideband pumping circuit on bank 1 sensor 1 — the ECU detects that the pumping-current control is pegged high or that the actual current required exceeds the expected ±2 mA window around lambda 1.0 to a degree that suggests a wiring short to power or to the 5V reference. On a healthy wideband, the pumping current sits within roughly ±2 mA across normal commanded lambda (negative current = lean exhaust, the cell is pumping oxygen out; positive current = rich, pumping oxygen in), and a circuit that's drawing far more current than that without a corresponding measurement is reporting an electrical fault rather than an exhaust condition. Cheapest-first: scan the wideband live data PID — a healthy bank-1 wideband at warm idle reads lambda 0.99-1.01 with pumping current oscillating gently around zero; a stuck-pegged reading or implausible current at idle is the electrical signature. Inspect the connector for a signal-to-5V short (corrosion bridging adjacent pins is the #1 cause). Backprobe the pump-cell wire and look for voltage above the normal 3V virtual-ground reference — anything pinned at battery voltage or 5V indicates a harness short. Verify the heater circuit (2-4 ohms cold) — a heater that's drawing too much current can drag adjacent signal wiring in shared connector bodies. Wideband replacements are pricier than narrow-bands, so confirm wiring before swapping parts.

Vehicle-specific patterns: 2007-2013 Toyota 2GR-FE / 2GR-FKS 3.5L V6 (Camry, Avalon, Highlander, Sienna) throws P2240 paired with P2237 when the OEM Denso wideband ages past 120k and the pumping circuit drifts out of spec; replace as a pair on V6/V8 since the opposite bank is usually within a year of failure. 2008-2014 Subaru EJ25 (Forester XT, WRX, Legacy GT) throws P2240 from connector contamination at the front O2 — Subaru's exhaust routing hits the wideband connector with road spray. 2010-2016 BMW N55/N20 turbo (3-series, 5-series, X1, X3) throws P2240 from a TSB-acknowledged harness issue and from wideband element degradation; OEM Bosch part runs $250-$350. 2009-2014 Honda 3.5L J35 V6 (Accord, Pilot, Odyssey, Ridgeline) throws P2240 less frequently than competitors but typically traces to a chafed front O2 harness at the engine mount bracket. Estimated repair: $200 to $550.