Fault code: 280 SCANIA

Error identification:

The voltage in the circuit has been above the permitted level.

Cause:

Possible causes:

• Open circuit in coolant temperature sensor circuit.

• Fault in the circuit for the charge air pressure sensor, charge air temperature sensor, fuel supply pressure sensor or fan speed sensor.

Notes:

There is a common voltage supply for the coolant temperature sensor, charge air pressure sensor, charge air temperature sensor, fuel supply pressure sensor and fan speed sensor. If a fault occurs in one of the sensors, the other sensor circuits may be affected.

If the voltage is outside the permitted range, the control unit uses a pre-programmed value. If the engine is actually colder than the pre-programmed value indicates, the engine will run worse when idling and will be harder to start.

The engine will run at fixed raised idling speed as long as the fault is active.

On engines with EGR, the engine control unit will switch off the EGR system.

The fault affects the vehicle s emissions of nitrogen oxides (NOx) and the lamp which warns about a high level of contaminants comes on in the instrument cluster. A text message is also displayed in vehicles with NOx monitoring.

Vehicles with NOx monitoring

An active fault code cannot be cleared from the control unit. When the fault has been rectified, the control unit must verify that the fault has been rectified in order for the fault code to become inactive.

Action:

Check that coolant and charge air are approximately the same temperature when the engine is cold.

Check the coolant temperature sensor, charge air pressure sensor, charge air temperature sensor, fuel supply pressure sensor and fan speed sensor, along with the circuits harness-to-harness connectors and electrical cables.

Proceed as follows to verify that the fault has been rectified:

Switch the ignition off and on with the starter key.

If the fault is resolved, the fault code becomes inactive. Clear the fault code.

Switch the power off and on with the starter key three times in succession at 10 second intervals to turn off the warning lamp.

Error identification:

The voltage in the circuit has been above the permitted level.

Cause:

Short circuit to battery voltage.

Power failure.

Notes:

A cold engine may be difficult to start and idling is uneven because the engine cannot engage the cold start position.

The engine power is reduced. On a vehicle with NOx control, the fault code must be deactivated before it can be deleted.

Action:

Check the circuit components, harness-to-component connectors and cable harnesses.