P1175, P1176
ENGINE CONTROL MODULE (ECM) - TRANSMISSION RELATEDMonitoring Procedure
This diagnostic monitors the communication to the Transmission Control Module (TCM). If the torque reduction request signal from the TCM holds at 12% for several seconds, the TCM is indicating to the ECM that a MIL Lamp illumination is required due to a fault in the TCM. The fault code is stored immediately.
If the TCM requests torque reduction from the ECM for too long, then the ECM recognizes that the signal is faulty and stores the Ignition Retard Request Duration fault code.