DTC 1-5-4 EGR System Leakage
1-5-4 EXHAUST GAS RECIRCULATION SYSTEM, LEAKAGEPreconditions for DTC
^ In order for the Exhaust Gas Recirculation (EGR) diagnosis to be active, it is necessary for: (a) the car to be started at an Engine Coolant Temperature (ECT) higher than -1O°C (14°F), (b) the engine to have been switched off after its previous run at an ECT higher than +80°C (176°F), (c) battery voltage to be above 12 Volts and (d) the ECT sensor to be undamaged. If the voltage at the EGR temperature sensor drops too much before engine coolant temperature has reached +60°C (140°F), the ECM interprets this as a sign of leakage, setting DTC 1-5-4.
Substitute value
^ Long term fuel trim inhibited.
^ The idle air trim is inhibited.
^ Only initial charge pressure is permitted.
Fault sources
^ The EGR controller's signal lead is short circuited to ground.
^ Defective vacuum hoses.
^ Defective EGR controller.
^ Defective EGR valve.
Fault symptoms
^ Engine may run unevenly at idling speed.
^ Poorer performance from initial charge pressure limit.