SYSTEM DESCRIPTION ENGINE IMMOBILISER SYSTEM DESCRIPTION The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses the transponder key ECU assembly that stores the key ID codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the transponder key ECU assembly sends a signal to the ECM to prohibit fuel delivery and ignition, effectively disabling the engine. FUNCTION OF MAIN COMPONENTS
SYSTEM FUNCTION (a) When the transponder key ECU assembly detects that the unlock warning switch assembly is on, the transponder key ECU assembly applies current to the transponder key coil and produces a magnetic field around the antenna coil. A transponder chip in the key grip outputs a key ID code signal using electromotive force generated by the magnetic field. The transponder key coil receives the signal and sends it to the transponder key ECU assembly. The transponder key ECU assembly checks if the key ID code received from the transponder key coil matches the registered key ID code. When the engine is started, the ECM communicates with the transponder key ECU assembly and checks the key verification result. In addition, the ECM checks if the engine ID codes stored in the transponder key ECU assembly and ECM match. If they do not match, the ECM prohibits engine start. |
Toyota Tundra Service Manual > Can Communication System: Check Bus 4 Lines for Short Circuit
DESCRIPTION There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 22 (CA2H) and 7 (CA2L) of the central gateway ECU (network gateway ECU) is below 54 Ω. Symptom Trouble Area *1: for 4WD *2: w/ Trailer Brake Control System Resistanc ...