DTC 2-2-4

FD. Fault code 2-2-4 REX-I

2-2-4 Engine temp. sensor signal absent or faulty



Conditions for fault code:
If the signal from the engine temperature sensor corresponds to a temperature below -40°C (-40°F) or above 120°C (250°F), the fault code is set.
The control unit then assumes an engine temperature of approx. 90°C (194°F) (limp-home) so that the car can still be driven.

Causes of fault:
Break or short circuit to ground in lines.
Connection resistance in connectors.
Poor chassis connection of signal ground.
Break or short circuit to ground in temp. sensor.

Fault symptoms:
None.

FD1




Checking of voltage supply
- Ignition on.
- Disconnect the sensor.
Connect a voltmeter between 2 in the connector and ground.
The voltmeter should show approx. 5 V.

If the value is OK:
^ Checking sensor resistance FD2

If the value differs:
^ Connection of measurement box FD3

FD2




Checking sensor resistance
- Ignition off.
- Sensor disconnected.
Connect an ohmmeter between 2 on sensor and ground.




The ohmmeter should show a value according to the diagram.

If the value is OK:
^ Connection of measurement box FD3.

If the value differs:
^ Test with a new sensor.

FD3




Connection of measurement box
Connect the measurement box to Rex-I and check the chassis connection according to N3-N4. N. Measurement Box, Signal Description
^ Continue with Checking of resistance to ground FD4.

FD4




Checking of resistance to ground
- Ignition off.
- Sensor disconnected.
Connect an ohmmeter between #2 and #20 (ground).
The ohmmeter should show infinite resistance

If the value is OK:
^ Checking of sensor and wire resistance FD5.

If the value differs:
^ Check the wires for short circuiting to ground according to CD. CD. Checking of Wiring

FD5




Checking of sensor and wire resistance
- Ignition off.
- Connect the sensor.
Connect an ohmmeter between #2 and #20 (ground).




The ohmmeter should show a value according to the diagram.

If the value Is OK:
^ Checking of signal to sensor FD6.

If the value differs:
^ Check the wire between #2 and the sensor for breaks and connection resistance according to CD. CD. Checking of Wiring

FD6




Checking of signal
- Connect the control unit to the measurement box.
- Insert fuse no.1.
- Ignition on.
Connect a voltmeter between #2 and #20 (ground).




The voltmeter should show a value according to the diagram.

If the value is OK:
Intermittent fault.
^ Check the connectors for loose connection according to CD. CD. Checking of Wiring

If the value differs:
^ Check the wires and connections for connector resistance according to CD. CD. Checking of Wiring