Fault code: 20481 SCANIA

Error identification:

A very large quantity of EGR gases returns even though the control unit has instructed the flap in the EGR valve to be fully, or almost fully, closed.

Cause:

The fault can be due to any of the following:

• The damper in the EGR valve cannot be closed.

• Leakage through the proportional valve.

• Blockage in the valve block channel for the relief valve which drains any remaining pressure.

• The mass flow sensor indicates too low a value. This results in the engine control unit assuming that the engine is receiving too high a volume of EGR gas.

• Fault in the fuel temperature sensor circuit or oil pressure sensor circuit.

Notes:

The engine control unit switches off the EGR system and calibration of the mass flow sensor is switched off.

There is a common voltage supply for the oil pressure sensor, fuel temperature sensor and mass flow sensor. If a fault occurs in one of the sensors, the other sensor circuits may be affected.

Action:

Check the damper in the EGR valve.

Check for leakage in the proportional valve.

Check whether pressure can be released via the valve block.

Check the oil pressure sensor, fuel temperature sensor and mass flow sensor, along with the harness-to-harness connectors and electrical cables in the circuits.