1.6.4.1 General description
The Injection Deactivation is a diagnosis to protect the catalysts from overheating. In fact it is an additional fuel pressure diagnosis with a very short diagnostic time and an early reaction with deactivation of some injectors. Additional there is an evaluation of the fuel tank level. If the tank level is low there will be a change of the DTC to provide better information's for the workshop.
The diagnosis evaluates first an air-fuel deviation. This check analyses the difference between the measured air fuel ratio and the set-point air fuel ratio and analyses the short term fuel trim. Both checks detect only the lean side of mixture. If a lean deviation occurs the diagnosis compares the difference between measured pressure and the setpoint of the high pressure and the absolute value of the high pressure sensor with a threshold or checks the absolute value of the low pressure sensor. Then a DTC is set and the reaction is the shut-off of an amount of injectors. This reaction avoids overheating of the catalysts. The decision of which DTC is stored will be affected by the fuel tank level ( 0 litre).