Diagnostic Procedure

Turn ignition switch to off position. Disconnect ECM and HO2S harness connectors. Measure resistance between ground ECM harness connector B136 terminals No. 13 and No. 22. If resistance is greater than 1 megohm, replace front HO2S and test system operation. If resistance is less than 1 megohm, repair short to ground between ECM harness connector and front HO2S. Clear memory and perform verification procedure. See CLEARING DIAGNOSTIC TROUBLE CODES  and VERIFICATION PROCEDURE  .