DTC 1-2-3

EG. Fault code 1-2-3 Regina

* 1-2-3 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 a coolant temperature of 20°C(68°F) at start-up and approx. 90°C(194°F) at all other times (limp-home) so that the car can still be driven.

Causes of fault:
Break or short circuit to ground in the wiring, connections or component.
Connection resistance in the connectors
Poor chassis connection of signal ground

Fault symptom:
Difficult to start when cold

REGINA #13 Water temp. signal missing



Condition for fault message:
Fault message if voltage is above approx. 4 V.

Cause of fault:
Break in wiring between #13 and temperature sensor.
Engine temp. sensor broken.

Fault symptom:
Difficult to start when cold.

EG1




Check of voltage supply
- Ignition on.
- Disconnect sensor.
Connect a voltmeter between 1 on the connector and ground.
The voltmeter should show approx. 5 V.

If the value is OK:
^ Checking the temp. sensor resistance EG2

If there is no voltage:
^ Connection of measurement box EG3

EG2




Checking the temp. sensor resistance
- Ignition off
- Sensor disconnected.
Connect an ohmmeter between 1 on the sensor and ground.




The ohmmeter should show a value according to the diagram.

If the value is OK:
^ Connection of measurement box EG3

If the value is incorrect:
^ Test with a new sensor

EG3




Connection of measurement box
Connect the measurement box and check the chassis connections according to N1-N2. N. Measurement Box, Signal Description
^ Continue with Checking of resistance to ground EG4

EG4




Checking of resistance to ground
- Ignition Off.
- Sensor disconnected.
Connect an ohmmeter between #13 and #5 (ground).
The ohmmeter should show infinite resistance.

If the value is OK:
^ Checking of sensor and wiring resistance EG5

If the value is different:
^ Check the wiring for signs of short circuit to ground according to CD. CD. Checking of Wiring

EG5




Checking of sensor and wiring resistance
- Ignition off.
- Connect the sensor.
Connect an ohmmeter between #13 and #5 (ground).




The ohmmeter should show a value according to the diagram.

If the value is OK:
^ Checking the signal EG6

If the value differs:
^ Check the wiring for signs of breaks and connection resistance according to CD. CD. Checking of Wiring

EG6




Checking the signal
- Connect the control unit to the measurement box
- Insert fuse no.1.
- Ignition on.
Connect a voltmeter between #13 and #5 (ground).




The voltmeter should show a value according to the diagram.

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

If there is no voltage:
^ Test with a new control unit

If there is another value:
^ Check the connectors with regard to connection resistance according to CD. CD. Checking of Wiring