| FAIL-SAFE CHART FAIL-SAFE FUNCTION (a) When a malfunction occurs in the tire pressure warning system, the tire pressure warning light illuminates after blinking for 1 minute to inform the driver of the system failure. (b) As a result of this, tire pressure monitoring is disabled and a DTC is stored in the tire pressure warning ECU and receiver. (c) When there is a system malfunction, the output display according to the tire position turns off.  | 
Toyota Tundra Service Manual > Sfi System: Random Access Memory (RAM) (P0604)
   DESCRIPTION The ECM continuously monitors its internal memory status. This self-check ensures that the ECM is functioning properly. This is diagnosed by internal "mirroring" of the main CPU and sub CPU to detect the Random Access Memory (RAM) errors. If outputs from these CPUs are different and devi ...