DTC 1-2-2

EF. Fault code 1-2-2 Regina

* 1-2-2 Air temp. sensor signal absent or faulty



Conditions for fault code:
If the signal from the temperature sensor is too high or too low, the control unit compensates with a value corresponding to approx. 20°C (68°F) (limp-home) so that the car can still be driven.
The fault code is set and the Check Engine lamp lights up.

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

Fault symptom:
Engine dies at idle.

REGINA #10 Air temp. low voltage



Conditions for fault message:
Fault message if voltage is below approx. 0.45 V.

Causes of faults:
Short circuit to ground in the sensor or in the wiring between #10 and the sensor.
Break in sensor or in the wiring between #6 and the sensor. Poor chassis connection.

Fault symptoms:
See above.

REGINA #10 Air temp. high voltage



Condition for fault message:
Fault message it the voltage is above approx. 4.2 V.

Causes of faults:
Break in wiring between #10 and sensor. Temp. sensor broken.

Fault symptoms:
See above.

EF1




Check of voltage measurement
- Disconnect the sensor.
- Ignition on.
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 EF2.

If the value is different:
^ Connection of measurement box EF3.

EF2




Checking the temp. sensor resistance
- Ignition off.
- Disconnect the sensor.
Connect an ohmmeter to the sensor between 1 and 2 (ground).
The ohmmeter should show approx. 2000 ohms at 25°C (77°F).

If the value is OK:
^ Connection of measurement box EF3

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

EF3




Connection of measurement box
Connect the measurement box and check the chassis connections according to N1-N2. N. Measurement Box, Signal Description

Important! The chassis connection to #5 is very important.

^ Continue with Checking of resistance to ground EF4

EF4




Checking of resistance to ground
- Ignition off.
- Sensor disconnected.
Connect an ohmmeter between #10 and #5 (ground).
The ohmeter should show infinity.

If the value is OK:
^ Checking the sensor and wiring resistance EF5

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

EF5




Checking of sensor and wiring resistance
- Connect the sensor.
- Ignition off.
Connect an ohmmeter between #10 and #6 (ground).
The ohmeter should show approx. 2000 ohms at 25°C (77°F).

If the value is OK:
^ Checking the signal EF6

If the value is different:
^ Check the wiring for signs of breakage and connector resistance according to CD.

EF6




Checking the signal
- Connect the control unit to the measurement box.
- Insert fuse no.1.
- Ignition on.
Connect a voltmeter between #10 and #6 (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 connections according to CD. CD. Checking of Wiring

If the voltmeter shows 0 V:
^ Test with a new control unit.

If there is a different value:
^ Check the connections with regard to connection resistance according to CD. CD. Checking of Wiring