EGR Temp. Sensor Signal Absent/Faulty (NTC)
FK. Diagnostic trouble code (DTC) 4-1-3
* 4-1-3 Exhaust Gas Recirculation (EGR) temperature sensor signal absent or faulty (NTC)
EGR system with an NTC type temperature sensor
To ascertain whether the EGR temperature sensor is an NTC or PTC type see the table In section FH. EGR System Flow Too Low (NTC)
For EGR systems with PTC type temperature sensors, see section FL. EGR Temp. Sensor Signal Absent/Faulty (PTC)
DTC conditions
The control module uses the signal from the EGR temperature sensor to determine whether there is an EGR 110w or not. if the control module receives a signal which is too high, too low or faulty (the temperature sensor signal changes when the control module is not sending an EGR flow), a DTC is logged.
Causes of fault:
- Faulty temperature sensor (break or short circuit in the sensor)
- Break in the signal wiring
- Signal wiring grounded
- Break in the wiring to GND
- Short circuit
- Intermittent loose contact
Note: Be careful when removing yellow and white hoses. The hoses may burst or crack if they are removed roughly from nipples.
FK1
Checking and cleaning the EGR temperature sensor connector
Contact resistance in the connector may cause the DTC to be logged. Carry out the following to eliminate contact resistance.
- Take the connector apart.
- Clean the terminals with anti-rust spray.
- Grease the connector. Grease P/N 1161417-9.
- Put the connector together.
- Remove the GND terminal (at the intake manifold), clean it and replace.
^ Continue with Checking the wiring to GND FK2.
FK2
Checking the wiring to GND
- Ignition off.
- Remove the connector at the EGR temperature sensor.
Connect an ohmmeter between terminal 2 on the temperature sensor wiring connector and GND.
The ohmmeter should read approx. 0 ohms.
If the reading is OK
^ check the signal wiring FK3.
If the reading is incorrect
^ check the wiring between terminal 2 on the temperature sensor connector and GND for breaks in accordance with NA2. NA. Checking the Wiring
FK3
Checking the signal wiring
- Ignition on.
- Connector disconnected.
Connect a voltmeter between terminals 1 and 2 on the temperature sensor wiring connector.
The voltmeter should read approx. 5 V if the signal wiring is OK.
If the voltmeter reads 0 V
^ check the signal wiring for breaks or short circuits in accordance with NA2 and NA3. NA. Checking the Wiring
If the voltmeter reads approx. S V
^ check the EGR temperature sensor FK4.
If the voltmeter reads over 5 V
^ check the wiring between sensor terminal 1 and terminal 22 on the control module for short circuits in accordance with NA4. NA. Checking the Wiring
^ If the signal wiring has been short circuited the EGR temperature sensor may have broken. Check the EGR temperature sensor in accordance with FK4 when the fault has been remedied.
FK4
Checking the EGR temperature sensor
- Connect the connector to the EGR temperature sensor.
- Engine idling.
Connect a voltmeter between terminal 1 on the temperature sensor connector and GND.
The voltmeter should read between 1.8-4.6 V depending on the temperature of the sensor. (1.8 V at approx. 80°C (176°F) and 4.8 V at approx. 0°C (32°F).) Note that the voltage over the sensor decreases with increasing temperature.
- Carefully remove the yellow hose at the EGR vacuum controller.
- Connect a vacuum pump to the hose to the EGR valve.
- Pump up a vacuum (max 30 kPa =4.3 psi).
The engine should idle badly while the voltage reading from the voltmeter should slowly decrease as temperature rises.
If the voltmeter reading is correct (1.8-4.8V) and decreases as above
Intermittent fault.
^ The temperature sensor is OK. Check the wiring and connections for loose contacts in accordance with NA5. NA. Checking the Wiring
If the voltmeter reading deviates or if the voltmeter reading does not decrease
^ try using a new temperature sensor (NTC type).