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EGR System Flow Too Low (PTC)



FJ. Diagnostic trouble code (DTC) 2-4-1 DI EZ 116 K (PTC)

* 2-4-1 EGR system flow too low (PTC)


EGR system with PTC type temperature sensor

See the table in section FH to check if the EGR temperature sensor is a NTC or PTC type. EGR System Flow Too Low (NTC)

EGR system with an NTC type temperature sensor, see section FH. EGR System Flow Too Low (NTC)




DTC conditions
- Cold engine (temperature below 6500 (149°F)) and rising temperature on the temperature sensor.
- Warm engine (above 65°C (149°F)), engine at part loads and the EGR signal does not change.

If the control module detects a change of over 60 mV In the EGR temperature sensor before the engine temperature has reached 65°C (149°F), it interprets this as an EGR flow and a DTC is logged.

When the control module sends a control signal to the EGR vacuum controller the signal from the EGR temperature sensor should change. If it does not do so the control module interprets this as a flow fault and logs the DTC.




Causes of fault:
- Faulty EGR valve (leaks or does not open)
- Faulty signal or no voltage to the EGR vacuum controller
- Faulty EGR vacuum controller
- Poor connection to GND
- Faulty engine thermostat
- Break in the signal wiring
- Poor vacuum to the EGR valve (in the white hose)
- Defective yellow hose (split, clogged)

Fault symptoms:
- The engine may idle unevenly.

Note: Be careful when removing yellow and white hoses. The hoses may burst or crack if they are removed roughly from nipples.


FJ1




Checking the idling
- Start the engine and listen to it running.

If the engine idles unevenly
^ check the signal wiring FJ2.

If the engine idles evenly
^ check the engine temperature FJ5.

FJ2




Checking the signal wiring
- Engine idling.
- Disconnect the connector from the EGR vacuum controller.

If the engine still idles unevenly
^ check the EGR vacuum controller FJ3.

If the engine now idles evenly
^ check the wiring between terminal 15 on the control module and terminal 1 on the EGR vacuum controller connector for grounding in accordance with NA3. NA. Checking the Wiring

FJ3




Checking the EGR vacuum controller
- Engine idling.
- Carefully remove the yellow hose from the EGR vacuum controller.

If the engine still idles unevenly
^ check the yellow hose FJ4.

If the engine now idles evenly:
^ try using a new EGR vacuum controller.

FJ4




Checking the yellow hose
- Engine idling.
- Carefully remove the yellow hose at the EGR valve.

If the engine now idles evenly
^ try using a new hose.

If the engine still idles unevenly
^ try using a new EGR-valve.

FJ5




Checking the engine temperature
- Engine running.
Check that:
1) the engine temperature rises normally,
2) the temperature gauge needle points straight up (90°) and that the upper radiator hose is hot.

If engine temperature rises slowly and the needle of the temperature gauge does not point straight up
^ try using a new engine thermostat.

If engine temperature is normal
^ check the connectors FJ6.

FJ6




Checking the connectors
Contact resistance in the EGR and ECT sensor connectors may lead to a DTC being logged.
- Switch off the ignition.
- Clean the EGR and ECT sensor connectors in accordance with NA7. NA. Checking the Wiring
- Disconnect the GND terminal (at the intake manifold), clean and replace the terminal.
^ Check that the EGR vacuum controller is operating FJ7.

FJ7




Check that the EGR vacuum controller is working
- Start and warm up the engine.
- Place your hand on the EGR vacuum controller and rev the engine (over 2000 rpm) several times. The EGR vacuum controller should tick.

If the EGR vacuum controller ticks (operates)
^ check the vacuum to the EGR vacuum controller FJ8.

If the EGR vacuum controller does not tick (is not operating)
^ check the voltage to the EGR vacuum controller FJ11.

FJ8




Checking the vacuum to EGR vacuum controller
- Engine running.
- Carefully remove the white hose from the EGR vacuum controller and check to see if there is a vacuum in the hose.

If there Is no vacuum
^ check the white hose between the EGR vacuum controller and the intake manifold. The hose should not leak or be clogged. Replace the hose if necessary.

If there is a vacuum
^ check the vacuum from the EGR vacuum controller FJ9.

FJ9




Checking the vacuum from the EGR vacuum controller
- Engine running.
- Connect the white hose to the EGR vacuum controller.
- Carefully remove the yellow hose from the controller.
- Connect a pressure gauge to the controller nipple.
- Rev the engine. Check that the controller lets a vacuum through. The needle on the pressure gauge gauge should oscillate rapidly.

If the needle on the pressure gauge does not oscillate
^ try using a new EGR vacuum controller.

If the needle on the pressure gauge does oscillate
^ check the EGR valve FJ10.

FJ10




Checking the EGR valve
- Engine running.
- Connect a vacuum pump to the yellow hose at the EGR vacuum controller.
- Pump up a vacuum (max.30 kPa-4.3psi). Check that the EGR valve moves, and holds the vacuum pressure. The engine should idle unevenly when the valve is open.

The three following alternatives are possible:

If the valve does not open
^ check to see if the yellow hose is clogged. If the hose is OK, try using a new EGR valve.

If the valve opens but loses vacuum
^ check the yellow hose for leaks. If the hose is OK, try using a new EGR valve.

If the valve opens and holds a vacuum, but the engine idles evenly
^ the EGR pipes are clogged. Clean the pipes.

FJ11




Checking the voltage to the EGR vacuum controller
- Switch off the engine.
- Ignition on.
- Disconnect the connector.
Connect a voltmeter between terminal 2 in the EGR vacuum controller wiring connector and GND.
The voltmeter should read battery voltage.

If this value is OK:
^ Check the signal wiring FJ12.

If the reading deviates (no voltage):
^ Check the wiring between the EGR vacuum controller terminal 2 and the ignition switch for breaks in accordance with NA2. NA. Checking the Wiring

FJ12




Checking the signal wiring
- Ignition on
Connect a voltmeter between terminals 1 and 2 in the EGR vacuum controller wiring connector.
The voltmeter should read 0 V.

If the voltmeter reads 0 V
^ check the signal FJ13.

If the voltmeter reads battery voltage
^ check the wiring for grounding in accordance with NA3. NA. Checking the Wiring

FJ13




Checking the signal
- Start the engine.
- Connect the voltmeter between terminals 1 and 2 on the EGR vacuum controller wiring connector.
Check the voltmeter while revving the engine a little.
The voltmeter should register a voltage for a moment before returning to 0 V.

If the voltmeter registers a voltage
^ try using a new EGR vacuum controller.

If the voltmeter does not register a voltage
^ check the wiring between terminal 1 on the controller connector and terminal 15 on the control module for breaks in accordance with NA2. NA. Checking the Wiring
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