DTC 1-5-4
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.
TESTING PROCEDURE
Checking the Idling Speed
^ START the engine and let it run at idling speed.
^ Listen to the engine.
If the engine runs unevenly at idling speed:
- Check the EGR controller's signal lead.
If the engine runs smoothly at idling speed:
- Refer to: Intermittent Fault section below.
Checking the EGR Controller's Signal Lead
^ Engine at idling speed.
^ Disconnect the EGR controller.
If the engine still runs unevenly at idling speed:
- Check the EGR controller.
If the engine now runs smoothly at idling speed:
- Check lead between EGR controller connector 1 and ECM A40 for signs of short circuiting to ground.
Checking the EGR Controller
^ Engine at idling speed.
^ Carefully undo the yellow hose from the EGR controller.
If the engine still runs unevenly at idling speed:
- Check the EGR valve.
If the engine now runs smoothly at idling speed:
- Test with a new EGR controller.
Checking the EGR Valve
^ Engine at idling speed.
^ Carefully undo the yellow hose from the EGR valve.
CAUTION: The EGR valve may be extremely hot!
If the engine still runs unevenly at idling speed:
- Test with a new EGR valve.
If the engine now runs smoothly at idling speed:
- Check if the yellow hose is blocked.
- Replace if necessary.
Intermittent Fault
^ Check the lead between the EGR controller connector 2 and ECM A4O for signs of intermittent short circuiting to ground.
^ Check that the EGR controller functions properly, using inspection function 3 (Diagnostic Test Mode 3).
^ Check that the EGR valve does not stick, use a vacuum pump.