DTC P1586 - Transmission Encoding Signal Not Rational
- Turn ignition on with engine off. Install scan tool to data link connector and check for DTCs. If DTC P1586 is present, go to next step. If DTC P1586 is not present, problem is intermittent. See INTERMITTENTS in TESTS W/O CODES article.
- Turn ignition off. Check continuity between inhibitor switch and ECM terminal No. 72 (White/Black wire). If continuity exists, go to next step. If continuity does not exist, repair open in White/Black wire between inhibitor switch and ECM.
- Check continuity between ground and ECM terminal No. 72 (White/Black wire). If continuity exists, repair short to ground in White/Black wire between ECM and inhibitor switch. If continuity does not exist, go to next step.
- After repairs, clear DTC. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM in TESTS W/O CODES - INTRODUCTION article. Retest system. If DTC resets, replace ECM. If DTC does not reset, system is okay.