DTC P1131: Front Ho2S Circuit Malfunction (Short Circuit) - Forester & IMPREZA 2.5L

Perform basic diagnostic procedure. See BASIC DIAGNOSTIC PROCEDURE . Turn ignition off. Disconnect ECM connector B136 (30-pin connector) and front HO2S connector. Using an ohmmeter, measure resistance between ECM connector B136 (30-pin connector) terminals No. 6, 7, 19 and 20 and chassis ground. See Figure. If resistance is more than 10 ohms, replace front oxygen sensor. If resistance is not more than 10 ohms, locate and repair short to ground in wiring between ECM and front HO2S. See WIRING DIAGRAMS article. Clear memory and perform verification procedure. See CLEARING DIAGNOSTIC TROUBLE CODES  and VERIFICATION PROCEDURE  .