Circuit Description

This DTC indicates that a transmission related fault has occurred. The TCM controls a dedicated Service Transmission Light (STL) that illuminates when a fault is reported by non-emissions related TCM diagnostics. TCM has no direct control of engine MIL, but if a transmission fault occurs that is emissions related, the MIL will illuminate. A bus circuit from TCM to ECM allows the ECM to illuminate the MIL even though the fault was detected by the TCM.